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Chassis Assignment 3 (Stress analysis) Assessment Title:

Bachelor of Engineering Technology

ENB6913

Programme Title:

Course No.:

Mechanical Project 4

Course Title:

Yahya Isa Saif

Student Name:

201001047

Student ID:

Syed Imam

Tutors:

Date submitted: 22-5-2014 Due Date: 22-5-2014

Date of Marking: Assessor:

Grade/Mark: /

Comments:

Assessment Cover Sheet

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Contents Contents ........................................................................................................................................................ 2

Table of figures: ............................................................................................................................................ 4

Table of Tables: ............................................................................................................................................. 5

Synopsis: ....................................................................................................................................................... 6

Introduction: ................................................................................................................................................. 7

Analysing situations: ........................................................................................................................ 8

Forces that act on the chassis: ....................................................................................................... 10

Tube properties: ............................................................................................................................. 11

Tubes material properties: ............................................................................................................. 11

Failure modes:............................................................................................................................................. 11

Static loading: ................................................................................................................................. 11

Cyclic loading (fatigue): .................................................................................................................. 14

Ductile and brittle failure: .............................................................................................................. 17

Fracture in ductile and brittle failure: ........................................................................................... 17

Crack Propagation (ductile material): ............................................................................................ 18

Fatigue failure (ductile materials): ................................................................................................ 19

Failure theories: .......................................................................................................................................... 19

Maximum shear stress: .................................................................................................................. 20

MAXIMUM DISTORTION ENERGY: ................................................................................................. 21

Maximum normal stress: ............................................................................................................... 21

Modified Mohr: .............................................................................................................................. 22

Factor of safety\ displacement: .................................................................................................................. 23

Displacement: ................................................................................................................................. 24

Finite Element Analysis: .............................................................................................................................. 24

Definition: ....................................................................................................................................... 24

Chassis (FEA) steps: ........................................................................................................................ 26

Chassis Finite Element Analysis: ................................................................................................................. 30

FEA analysis during braking: .......................................................................................................... 30

Strain analysis: ................................................................................................................................ 32

Displacement analysis: ................................................................................................................... 32

FOS: ................................................................................................................................................. 34

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FEA analysis during Acceleration: .................................................................................................. 35


FOS: ................................................................................................................................................. 38

FEA analysis during Cornering: ...................................................................................................... 39


FOS: ................................................................................................................................................. 42

Methods of joining: ..................................................................................................................................... 43

Selection of method of joining: ..................................................................................................... 46

Heat treatment: .......................................................................................................................................... 47

Post weld heat treatment (PWHT) (Stress relieving): ................................................................... 47

Conclusion and future recommendations (optimization): ......................................................................... 50

Appendix (A)................................................................................................................................................ 51

Appendix (B) ................................................................................................................................................ 52

Appendix (C) ................................................................................................................................................ 53

Appendix (D) ............................................................................................................................................... 54

Reference: ................................................................................................................................................... 84

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Table of figures: Figure 1, Gravity and longitudinal acceleration (acceleration) ..................................................................... 7 Figure 2, Gravity and longitudinal acceleration (braking)............................................................................. 7 Figure 3, Gravity and lateral acceleration (cornering) .................................................................................. 7 Figure 4, forces that effect on vehicle during cornering (front view) ( milliken , 2002) ............................... 8 Figure 5, vehicle reaction force. (Nuffield Foundation, 2011) ...................................................................... 9 Figure 6 creep test specimen (Suranaree University of Technology, 2007) ............................................... 12 Figure 7, stress versus strain (Suranaree University of Technology, 2007) ................................................ 12 Figure 8, Stress versus rupture time (Suranaree University of Technology, 2007) .................................... 12 Figure 9 Strain versus time (Suranaree University of Technology, 2007) ................................................... 13 Figure 10 creep rate versus strain (Suranaree University of Technology, 2007) ........................................ 13 Figure 12 creep strength curve (Suranaree University of Technology, 2007) ............................................ 13 Figure 12 creep data curve (Suranaree University of Technology, 2007)................................................... 13 Figure 13, Sinusoidal loading (fatigue test, 2013)....................................................................................... 14 Figure 14, Sinusoidal loading (fatigue test, 2013)....................................................................................... 15 Figure 15, spectrum loading (fatigue test, 2013) ........................................................................................ 15 Figure 16, Ferrous and nonferrous S-N curves (S-N curves, 2011) ............................................................. 15 Figure 17, stress versus strain graph (Tensile properties, 2012) ................................................................ 16 Figure 18, ductile and brittle materials. ...................................................................................................... 17 Figure 19, ductile and brittle fracture (ductile and brittle fracture, 2008) ................................................. 17 Figure 20, Neck (Ductile Fracture 2, 2013) ................................................................................................. 18 Figure 21, Micro voids (Ductile Fracture 2, 2013)....................................................................................... 18 Figure 22, Coalesce (Ductile Fracture 2, 2013) ........................................................................................... 18 Figure 23, Fracture (Ductile Fracture 2, 2013) ............................................................................................ 18 Figure 24. microvoid and shear slip (Ductile Fracture 2, 2013) .................................................................. 18 Figure 25, Cup and cone fracture. (Duralumin, 2013) ............................................................................... 19 Figure 26, fatigue failure. ............................................................................................................................ 19 Figure 27maximum shear stress (failure theories, 2010). .......................................................................... 20 Figure 28 Von Mises stress (Failure Criteria, 2013) ................................................................................... 21 Figure 29 Maximum normal stress (Failure Criteria, 2013) ....................................................................... 21 Figure 30Mohr's Circle (Failure Criteria, 2013) ........................................................................................... 22 Figure 32, Meshing system (FEA). (sciepub, n.d.) ....................................................................................... 25 Figure 33, selecting the material for the chassis. ....................................................................................... 26 Figure 34, converting the chassis to solid. .................................................................................................. 26 Figure 35, putting the fixtures. ................................................................................................................... 27 Figure 36, adding the acceleration. ............................................................................................................ 27 Figure 37, applying the material for chassis components. ......................................................................... 28 Figure 38, creating the component contact. .............................................................................................. 28 Figure 39, creating the contact set ............................................................................................................. 28 Figure 40, creating a mesh. ......................................................................................................................... 29 Figure 41, vehicle components. .................................................................................................................. 29 Figure 41, Stresses on the chassis ............................................................................................................... 30 Figure 42, Stresses on side bottom members ............................................................................................ 31 Figure 43, strain on the whole chassis. ....................................................................................................... 32 Figure 44, displacement on the whole chassis. .......................................................................................... 33 Figure 45, FOS during braking ..................................................................................................................... 34 Figure 46, Stresses on the chassis during acceleration............................................................................... 35

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Figure 47, Stresses on side bottom members ............................................................................................ 36 Figure 48, displacement on the whole chassis (during acceleration) ......................................................... 37 Figure 49, FOS during acceleration ............................................................................................................. 38 Figure 50, Stresses on the chassis ............................................................................................................... 39 Figure 51, Stresses on side bottom members ............................................................................................ 40 Figure 52, displacement on the whole chassis (during acceleration) ......................................................... 41 Figure 53, FOS during cornering ................................................................................................................. 42 Figure 42, welding machine (hotrod, 2010) ................................................................................................ 43 Figure 43, MIG and TIG welding (mechanical-engineering, 2011) ............................................................. 44 Figure 44, Brazing (Brazing practice, 2013) ................................................................................................ 45 Figure 45, Gas blow torch (directindustry, 2011) ....................................................................................... 46 Figure 46, welding structure parts (section view) (BASIC WELDING, n.d.) ................................................. 47 Figure 47, Residual stress versus soaking time (PWHT Determines the Quality of Weldments, 2012) ..... 48 Figure 60, Residual stress versus reliving temperature .............................................................................. 48 Figure 61, typical thermal treatments for weldment. (Khan, 2007) ........................................................... 49 Figure 50, finding the chassis mass in KG through using solid work software. .......................................... 51 Figure 51, creep test device. (CREEP TESTING MACHINE, n.d.) .................................................................. 52 Figure 52, tensile test device. (matcsi, 2010) ............................................................................................. 52 Figure 65, failure theory (Failure Mechanics, 2013) ................................................................................... 53 Figure 66, failure theory (Failure Criteria, 2013) ........................................................................................ 53

Table of Tables: Table 1, forces on the chassis ..................................................................................................................... 10 Table 2, tubes dimensions .......................................................................................................................... 11 Table 3, mild steel (AISI 1020) properties (abstained from solid works) .................................................... 11 Table 3, decision matrix .............................................................................................................................. 46

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Synopsis:

The main aim of this assignment is to analyse various types of the stresses that are acting on

the chassis during cornering, acceleration and braking; this report consists of nine sections. The

first section is an introduction; it shows the forces on the chassis (gravitational force and lateral

or longitudinal force). The second section is failure mode; it analyses various types of failure

modes. The third section is failure theory; it shows some of theories for both ductile and brittle

materials. The forth section is failure criteria; it estimates the FOS and the maximum deflection

for the design. Finite Element Analysis is the fifth section; it defines the meaning of the concept

(FEA), and shows the steps for doing the analysis for the chassis. Chassis Finite Element Analysis

is the sixth section; it analyse the stresses, displacement and FOS on the chassis during

acceleration, braking and cornering. Method of joining is the seventh section; t shows various

type of joining methods, and selects one of them for manufacturing the chassis. Heat treatment

is the eighth section; it demonstrates post weld heat treatment process. The last section is

conclusion which is summary of the entire report outcome.

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Introduction:

The main aim of this report is to analyse the stresses that act on a chassis that designed

and modified by me in order to estimate whether if the initial design can withstand the forces

that are acting on it, if it is suitable for the racing fields or not and if the design requires some

modifications (optimisations). To achieve this aim I will use Finite Element Analysis (FEA)

feature in solid-works software to analyse the whole structure of the chassis; specifically I will

use assembly feature in order to add the components of the car (engine battery, etc.) on the

chassis as a loads that are acting on it as shown on the figures below; I will add two force as

well which they are the gravitational acceleration that acts downward, also the longitudinal

acceleration due to weight transfer during braking or acceleration or lateral acceleration during

cornering as shown on the figure below:

Figure 1, Gravity and longitudinal acceleration (acceleration)

Figure 2, Gravity and longitudinal acceleration (braking)

Figure 3, Gravity and lateral acceleration (cornering)

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Figure 4, forces that effect on vehicle during cornering (front view) ( milliken , 2002)

Z

Analysing situations:

In this repot I will simulate the chassis design through using FEA in Solid-Works software

in three different situations which they are acceleration, braking and cornering. The total stress

on the design, the displacement and FOS where the minimum actual FOS is 2 (see FOS section)

will be analysed in order to test the design stiffness and durability. To analyse the design I

should place the vehicle components (engine, battery, ETC) with their specific weights on the

chassis. In addition, I should find the lateral acceleration during cornering and longitudinal

acceleration during acceleration and braking:

Lateral Acceleration during cornering:

Assuming that the cornering is in a steady condition where the driving in a smooth road,

the cornering at constant speed and a constant longitudinal acceleration.

Where,

1. : Centre of gravity = W = 6521.9 N. 2. : Centre of gravity height 0.403 m. 3. : The weight of the left hand side of the vehicle. 4. : The weight of the right hand side of the vehicle. 5. : The track width 1.67m.

6. : The lateral acceleration =

.

During cornering the centripetal force is equal to the frictional force, to find the

maximum turning velocity we assumed that the turning in a corner with a radius of 100

m:

The friction force = =

The centripetal force =

√

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Figure 5, vehicle reaction force. (Nuffield Foundation, 2011)

√ = 29.7 ⁄

⁄ (Harbin, 2013)

Lateral acceleration (a) =

⁄

Longitudinal Acceleration during braking and acceleration:

The vehicle mass 635.64Kg.

The vehicle weight is .

The friction coefficient between the tire and the dry road is 0.9.

The reaction force is .

The friction force =

The acceleration or the deceleration can be found through using Newton’s Second law which

is .

⁄

Another method, the acceleration is equal to the gravity multiplies by the frictional force:

⁄

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Forces that act on the chassis:

Part Mass in Figure:

Chassis without roll cage mass 92Kg(obtained from solid-works) see

appendix A

Radiator 12Kg

Battery 11.8Kg

Fuel tank 33Kg

Two Passengers 150Kg

Engine + transition 200Kg

Assembly

Table 1, forces on the chassis

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Tube properties:

Tube size: Location:

25 mm square tube with 2 mall wall thickness

All of the chassis except the side members and roll cage

21 mm square tube with 2 mall wall thickness

For side members only.

38 mm diameter round tube with 3 mm wall thickness

For the roll cage (I did not analyze it due to an

error during simulation) Table 2, tubes dimensions

Tubes material properties:

Material name: AISI 1020

Default failure: Max von Mises Stress

Yield strength: 351.571 (MPa)

Tensile strength: 420.507 (MPa)

Elastic modulus: 200000 (MPa)

Poisson's ratio: 0.29

Mass density: 7900

Shear modulus: 77000 N/(MPa)

Thermal expansion coefficient: 1.5e-005 /Kelvin Table 3, mild steel (AISI 1020) properties (abstained from solid works)

Failure modes:

Static loading:

Static loading is a stationary force or couple applied to a material, and to be stationary

the force or the couple must be constant in the magnitude, in the point or points of application,

and in the direction. There are many examples of static loading forces such as, axial tension or

compression, a shear load, a bending load, or any combination of these. In addition, the

material starts yielding (become permanently distorted) or fail (separated into two pieces or

more) if the applied stress (load) exceeds the material’s strength (UTS). For instance, during

static the chassis is subjected to a bending stress due to the weight of car components (battery,

engine, etc.) that are placed on the chassis; where if the chassis not stiff enough it’s member

(square tubes) will bend during static. In addition, two tests are important for static loading

which they are Creep test and rapture test.

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Figure 6 creep test specimen (Suranaree University of

Technology, 2007)

Figure 8, Stress versus rupture time (Suranaree University of Technology, 2007)

Figure 7, stress versus strain (Suranaree University of Technology, 2007)

Creep test:

Creep is a concept used when a material is subjected to a constant load like a tension

load; the length of the material will increase through the increasing of the time until the

material fail, therefore, it is a time-dependent failure mechanism. (Suranaree University of

Technology, 2007)

There are two main examples of creep applications:

1. Creep test:

The creep test measures the dimensional changes that occur through

applying a constant load to a tensile specimen maintained at a constant

temperature, (Suranaree University of Technology, 2007)

From the figure above the shape of creep curve will slightly change according to the

magnitude of the applied stress at a constant temperature where the higher load is the more

strain and faster failure

2. Rupture test:

The rupture test measures the effect of temperature on the. It is similar to the creep

test since the material is subjected to a higher stress level until the material fails and the time

at failure is measured. (Suranaree University of Technology, 2007)

As shown on the figure above the rupture strength and the time of failure are plotted in

a straight line and the changing of the slope refers to the structural changes in the material.

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Figure 9 Strain versus time (Suranaree University of

Technology, 2007)

Figure 10 creep rate versus strain (Suranaree University of Technology, 2007)

Creep stages: When applying a constant tensile load on a material, the martial will deforms in

three stages:

The first stage called primary creep where the creep rate is

decreasing and the creep resistance of the material increases to

material deformation.

The second stage called Secondary creep that shows a nearly

constant creep rate, and the average value of the creep rate

during this period is called the minimum creep rate.

The last stage is tertiary creep; it shows a rapid increase in the

creep rate because of the effectively reduced cross-sectional

area of the material. (Suranaree University of Technology, 2007)

Creep deformation processes:

In the first stage the deformation occurs by slip systems; more slip

systems operate at high temperature and slip bands are coarser

and widely spaced.

The second stage is Subgrain formation; the Creep deformation

produces imhomoginiety especially around grain boundaries, letting

dislocations to arrange themselves into a low-angle grain boundary.

The last stage is grain boundary sliding; and it produced through the

shear process and promoted by decreasing strain rate or increasing

temperature. (Suranaree University of Technology, 2007)

Two of the most important curves for engineers and designers are creep data curve and creep

strength curve:

Creep strength curve: shows a material stress at a given temperature, which produces a

steady-state creep rate. (Suranaree University of Technology, 2007)

Creep data curve: shows a plot of the material stress and time to produce different

amounts of total strain. (Suranaree University of Technology, 2007).

Figure 12 creep strength curve (Suranaree University of Technology, 2007) Figure 12 creep data curve (Suranaree University of Technology, 2007)

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Figure 13, Sinusoidal loading (fatigue test, 2013)

Cyclic loading (fatigue):

When an object is made from a specific material is subjected to vibrating or oscillating

forces such as, sitting on and standing from a thin chair continuously until it breaks; the failure

mechanism of materials under repetitive loads called fatigue failure. Furthermore, fatigue is a

concept refers to a material becomes “tired” and will fail at a stress level below the yield

strength of the material. Material fatigue is an important point for engineers to study because

statics indicate to fatigue failure is the responsible for 90% of all failures of metallic structures

such as bridges and machine components failure. (Failure Mechanics, 2013).

The three stages of fatigue:

First a microscopic crack will begin to form called the initiation site.

Under the cyclic loading the microscopic crack starts to propagate.

The material fails when the crack grows large enough. (Failure Mechanics, 2013)

Loading types:

Fatigue cracks initiate begin to form based different factors such as, the loading pattern

must contain minimum and maximum peak values with a large enough of variation between

the amplitudes, the reverse loading cycle and the peak stress must be sufficiently high; since if

the peak stresses are too low no crack initiation will occur also the material must experience a

sufficiently large number of cycles of the applied stress. (fatigue test, 2013)

There are two types of loading that could initiate a fatigue crack, which they are sinusoidal

loading and spectrum loading:

Sinusoidal loading is divided into two types. The first type occurred when the loading is

going from a tensile stress to a compressive stress. In this type of loading (stress cycle) the

maximum and minimum stresses are equal. Tensile stress is considered as the positive

cycles, and compressive stress is the negative cycles as shown on the figure below:

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Figure 14, Sinusoidal loading (fatigue test, 2013)

Figure 15, spectrum loading (fatigue test, 2013)

Figure 16, Ferrous and nonferrous S-N curves (S-N curves, 2011)

The second type of sinusoidal loading that causes also materials fatigue is a loading with the

minimum and maximum stresses both in the tensile as shown on the figure below:

The second type of loading is spectrum loading that the loading has variable-amplitude on

the graph; for example, when the chair experiences changing in loading patterns.

Furthermore, in variable-amplitude loading, cycles that exceeding some peak threshold will

aid to fatigue cracking. The figure below shows spectrum loading graph: (fatigue test, 2013)

S-N curve Curves:

S-N curve curves show the relation between the alternating stress amplitude ( ) versus

number of cycles ( ) to failure:

There are two distinct types of S-N curves:

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Figure 17, stress versus strain graph (Tensile properties, 2012)

The first type of S-N curves occurred in ferrous (iron based) alloys like carbon steel, which

the stress amplitude starts decreasing through the increasing number of cycles until the

curve becomes horizontal which means through the increasing number of cycles the stress

will remain the same, therefore the material will not fail, this called fatigue limit or

endurance limit. (the upper curve) (Failure Mechanics, 2013).

The second type of S-N curve occurred in Nonferrous alloys like Aluminium that there is no

fatigue limit for the material, thus the S-N curve continues downwards and fatigue failure

will occur after a certain number of cycles.(the lower curve) (Failure Mechanics, 2013)

Tensile test:

Tensile test is a mechanical test where any material is subjected to a pulling force from

both sides until the material specimen changes its shape or break. From this test, much

information about the material can be tested such as, percentage of elongation(less than 5%

brittle or more than or equal 5% ductile), yield point, tensile strength, ultimate strength of the

material and the material ductility. In addition, this test shows how a material reacts when

tension force is applied to it. (Tensile strength, 2013). Furthermore, stress (the forced applied

divided by the cross sectional area before the testing) and strain (material elongation divide by

the original length of the material) are found in order to draw the Stress versus strain diagram,

which represent the relationship between the load applied to the material and the deformation

of the material (ductile or brittle), caused by the load. (Tensile properties, 2012)The graph

below shows the result of a tensile test for a ductile material:

From the graph above the stress versus strain graph has three stages. In the first stage

the curve starts increasing in a linear curve until it reaches to a point called the yield point,

which is a transition point that when the applied force exceeds it the material will deform

permanently, and the slope of the linear line (difference in stress divided by difference in strain)

represent the young modulus of the material (stiffness), which is the ability of material to

undergoes stress, deforms, and then returns to its original shape after the stress is

removed. The second stage called uniform plastic deformation; it starts after the Yield point

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Figure 18, ductile and brittle materials.

where the curve increasing uniformly until it reaches to the highest point of the curve which

represents the ultimate tensile strength (UTS) of the tested material. Furthermore, the

maximum stress level reached in this test (UTS) represents the material ability to withstand

external forces without breaking. The last stage is non-uniform plastic deformation that the

curve starts decreasing until it reaches to the fracture point that the material cut into two

pieces. (tensile, 2012).

Ductile and brittle failure:

Ductile materials are materials deform before fracturing, and the material ductility is

measured by finding the percentage of elongation at the fracture point. Materials that have 5%

or more percentage of elongation are considered as ductile, while when the material

elongation is below than 5% it considered as brittle material. Furthermore, brittle material

yields very little before fracturing, the yield strength is approximately equal to the ultimate

tension strength. (Static loading theory, 2011). Mild steel grade 1020 is a type of ductile

materials.

Fracture in ductile and brittle failure:

The figure above (part A) shows the fracture in ductile material that called cup and

cone; since, part B shows the fracture in brittle material where the cut is street and the surface

of it is rough.

Figure 19, ductile and brittle fracture (ductile and brittle fracture, 2008)

A B

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Figure 24. microvoid and shear slip (Ductile Fracture 2, 2013)

Crack Propagation (ductile material):

The crack continues to grow during this stage as a result of repetitive loadings. In ductile

materials the crack propagation occurs in several steps.

Initially as a result of the tensile load, the material stretches and experiences plastic

deformation. Beyond some point the material will begin to neck: (Ductile Fracture 2, 2013):

With continuing stress the material continues to plastically deform and small openings

begin to appear inside the material at the centre of the necked region. These holes are known

micro voids (Ductile Fracture 2, 2013):

The micro voids grow and coalesce from a continuous cavity within the centre of the

necked region. Once the cavity in the centre of the specimen reaches a certain size the sample

will fail by fast fracture (Ductile Fracture 2, 2013):

The fast fracture region typically occurs at 45 degree to the plane of the tensile load (the

angle at which the shear load is the greatest).This result in a lip around the fracture surface.

(Ductile Fracture 2, 2013):

The flat region which resulted from the initial microvoid

coalescence is typically quite rough in appearance while the surface of the

shear lip is typically quite smooth. (Ductile Fracture 2, 2013)

Neck

Figure 20, Neck (Ductile Fracture 2, 2013)

Micro voids

Figure 21, Micro voids (Ductile Fracture 2, 2013)

Coalesce

Figure 22, Coalesce (Ductile Fracture 2, 2013)

Figure 23, Fracture (Ductile Fracture 2, 2013)

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Fracture shape:

The left picture represents the cone and it consists of two regions; the first region in the

middle is the flat region which resulted from the initial microvoid coalescence. The second

region is the surface of the shear lip is typically quite smooth. The right picture is the cup, it

consist also with two regions, rough in the middle and smooth in shear slip.

Fatigue failure (ductile materials):

The figure above shows failure in a pedal (for ductile material) arm failed because of

fatigue failure; it’s obvious that the fracture surface consist of two distinct regions; the first

one(the bigger and lighter region) is smooth (burnished) produced as a result of the rubbing of

the bottom and top of the crack as it is growing. The second is granular, produced as a result of

the rapid failure of the material, it contains marks called clamshell marks (beach marks), these

marks produced through the crack propagation, and the distance of them depends on the

stress magnitude. (fatigue, n.d.).

Failure theories: If a material is subjected to increasing loads it eventually fails. Furthermore, it is easy to

estimate the point of failure of a material that is subject to a tensile force, since it is more

complicated to determine the points of failure when the material is subjected to a number of

loads in different directions where some of them are tensile loads, and some of them are shear

loads. Scientists developed many theories for calculating the stresses. For instance, there is

maximum shear stress theory and maximum distortion energy (von Mises stress for ductile

materials) for ductile materials. Since there is Maximum normal stress, and Modified Mohr for

brittle materials; there is more theories but I don’t have enough time to explain more.

Figure 25, Cup and cone fracture. (Duralumin, 2013)

Figure 26, fatigue failure.

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Maximum shear stress:

Maximum shear stress occurs in ductile materials, which the plane Stress only. When the maximum shear stress exceeds the material Strength , thus the material yields. Furthermore, for a given plane the maximum in-plane shear Stress is equal to the average of

the in-plane principal Stresses:

, (failure theories, 2010)

The two maximum Out-of-Plane Shear Stresses are:

is the Maximum Shear Stress.

is the Maximum Principal Stress.

is the Minimum Principal Stress.

Note that the out-of-plane principal stress ( ) for the strain plane condition is zero.

The failure occurs when the maximum of the Three Maximum Shear Stresses reaches the shear yield stress .

From the figure above failure occurs if the in-plane principal Stresses lie outside the shaded zone.

Under a Uniaxial load, .Thus, the axial yield stress is = = .

The Maximum Shear Stress Theory predicts that the Shear Yield Stress is half the Axial Yield

Stress.

When the In-Plane Principal Stresses are the same sign (1st and 3rd quadrant), the

Maximum Shear Stress in the system is Out-of-Plane. When the In-Plane Principal Stresses

are opposite sign (2nd and 4th quadrant), the Maximum Shear Stress in the system is In-

Plane. (Failure Criteria, 2013)

In short, in Max Shear Stress the material fails when:

Figure 27maximum shear stress (failure theories, 2010).

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Figure 28 Von Mises stress (Failure Criteria, 2013)

Figure 29 Maximum normal stress (Failure Criteria, 2013)

Factor of Safety:

MAXIMUM DISTORTION ENERGY:

First, Von Mises Equivalent Stress ( ) defined as the Uniaxial tensile stress that creates the same distortion energy as any actual combination of applied stresses. In addition, ductile materials will fail when the Von Mises Equivalent Stress ( ) exceeds the Axial Yield Stress ( ). The von Mises Equivalent Stress

is defined by: (failure theories, 2010)

Von Mises equation:

Total stress ( ) = √

The material fails (yields) when

Factor of Safety:

Maximum normal stress:

Is a state happens when the maximum normal stress in any direction of a brittle material reaches to the material strength, therefore the material fails.

1. In tension stress failure occurs when: 2. In compression stress failure occurs when:

Where,

is the stress applied on the material.

: is the ultimate strength in Tension

: is the ultimate strength in Compression

In brittle materials is much greater than .

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Modified Mohr:

The Mohr Theory of Failure (Coulomb-Mohr criterion or internal-friction theory) is based on the famous Mohr's Circle. Mohr's theory is used in predicting the failure of brittle materials. Mohr's theory suggests that failure occurs when Mohr's Circle at a point in the body exceeds the envelope created by the two Mohr's circles for uniaxial tensile strength and uniaxial compression strength. This envelope is shown in the figure below. (Failure Criteria, 2013)

The left circle is for uniaxial compression at the limiting compression stress sc of the

material. Likewise, the right circle is for uniaxial tension at the limiting tension stress.

The middle Mohr's Circle on the figure (dash-dot-dash line) represents the maximum

allowable stress for an intermediate stress state.

All intermediate stress states fall into one of the four categories in the following table. Each

case defines the maximum allowable values for the two principal stresses to avoid failure.

(Failure Criteria, 2013)

Figure 30Mohr's Circle (Failure Criteria, 2013)

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Factor of safety\ displacement:

The factor of safety (FOS) can be estimated through specifying five elements which they are; the properties of the material, the applied stresses, geometry, failure analysis and the desired reliability.

Estimating the contribution for the material :

The properties of the material (the specific chosen material for the chassis) will be obtained from Solid Works software or from a trusted internet source like (mat-web). Therefore, all of the properties are well known; though we will not do a special test to ensure the properties of the specific chosen material. However, the supplier do not grantee that the tubing sections have a constant thickness where some points of the tubes may be thinker or thinner than the spiced thickness. In addition, the material can expose to some of the environmental conditions such as, corrosion and rust that lead to the material wear. Therefore we will put the safety factor as 1.1

Estimating the contribution for the load stress :

In this part the nature of the loads that act on the vehicle during static, acceleration, declaration, cornering and bumping are well known as a separate situation. In combined situations like acceleration and cornering in the same time or bumping and cornering in the same time the loads are not well known. Therefore we will put the safety factor as 1.2.

Estimating the contribution for geometry :

The students will build the chassis manually by their self and due to the lack of welding experience for the reason that most students did not weld anything before or study a welding course; therefore, there is a big possible that the manufacturing dimensions will be out of tolerances and not closely held. Therefore we will put the geometry safety factor as 1.15.

Estimating the contribution for failure analysis :

The failure analysis is not well developed where we did not calculate the failure due to cumulative damage or fatigue stresses. Therefore we will put the failure analysis safety factor as 1.2.

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Estimating the contribution for reliability :

Solid works software uses thousands of equations to analyse the stress on each small part

of the wishbone (software splits the wishbone into thousands of meshes); therefore, we can

rely on sold works simulation; since it’s still theoretical calculations Therefore I will put the 1.1

as safety factor for reliability.

Therefore,

Displacement:

The allowable range of displacement for the chassis design should be 1 mm or lower; I

selected 1 mm as a maximum displacement for several reasons first is to provide stable driving

without any sudden shocks (good for handling), also, to do not effect on the suspension

geometry (camber, caster and toe) due to the chassis is connected with suspension system so

the large displacement will effect on the suspension geometry which leads to tires wear and the

instability of the vehicle as well. Furthermore, I select 1 mm to avoid the design failure.

Finite Element Analysis:

Definition:

Finite Element Analysis (FEA) is computer program uses a finite element technique to study

a design with a specific material; it analyses how the applied loads (stresses) will effect on the

design through giving specific results (graphs and tables). FEA analysis is done through

generating a mesh of points in a shape of the design that has information about the used

material properties and the design at each point for the doing the analysis. The benefits of

(FEA) are, it can assist in finding the design reactions against the stresses that are acting on the

design, it can analyse the effect of heat transfer, fatigue and vibration as well. The main benefit

of (FEA) it can help in finding the weakness points in the design before manufacturing it, and

determining the design required modifications to meet the design requirements

(specifications). (Introduction to Finite Element Analysis, 2008).

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FEA types:

There are two methods can be used for the analysis, modelling and modelling;

the modelling is simple and lets the analysis to be run on normal computers

(recommended for building 30 computers), however, it gives less accurate results. Since, the

modelling, generates more accurate results (requires fast computers with high

specifications such as Ram, processor, etc.). In both modelling methods, the programmers can

add numerous functions in order to make the system behave linearly or non-linearly. The linear

systems are less complex; typically they do not take into account the plastic deformation. The

non-linear systems analyse the plastic deformation, test a material in a specific design in all the

way to fracture, etc. (Introduction to Finite Element Analysis, 2008)

Meshing system in FEA:

In FEA the software (any software applies FEA) uses very complicated system of points

called nodes; these nodes create a mesh on the tested design as shown on figure below. The

mesh is programmed to have the material and design properties which describe how the

structure will react to the stress that the design will expose to. (Introduction to Finite Element

Analysis, 2008)

The loads that can be applied in FEA:

1. Pressure, thermal, centrifugal static loads and the gravity.

2. Thermal loads that are from solution of heat transfer analysis.

3. Convection and heat flux.

4. Gravity dynamic loads.

5. ETC (based on the used software). (Introduction to Finite Element Analysis, 2008)

FEA gives a results for maximization and minimisation of:

1. Displacement, velocity, acceleration and force.

2. Volume, temperature, mass.

3. Stress and strain energy.

4. Synthetic (User defined). (Introduction to Finite Element Analysis, 2008)

Figure 31, Meshing system (FEA). (sciepub, n.d.)

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Chassis (FEA) steps:

In order to analyse the chassis and the stress that are acting on it, we should do some steps

in order to get right simulation without any error; the table below shows the steps for doing the

FEA in solid-works:

1. Applying the material to the chassis:

Before doing this step we should go to new study than static.

Click on apply material (1) than Choose the required material (2), and finally apply the changes than close the window (3).

2. Converting the chassis members to solid bodies:

Click on parts than chassis file (1) than select all of the chassis members (2), and finally click on treat as a solid (3). The purpose of step is to convert the chassis from beams to a solid to assemble it with remaining members.

Figure 32, selecting the material for the chassis.

Figure 33, converting the chassis to solid.

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Now go to assembly option insert the vehicle components, than choose mate option; finally connect the face of the component with the face of the required chassis member through using coincident option. For the engine part, for the engine part I assembled it directly on the bottom layer members since it is an approximated position; I can put it in a right way but this will creates some errors in my simulations.

3. Adding the fixtures:

Click on fixture advisor (1) than Choose fixed geometry (2); select the required faces that you should put the fixture on them than apply the changes (3).

4. Adding the acceleration:

Click on external force (1) than select gravity (2), add the normal gravity (3).Finally add the longitudinal acceleration or lateral acceleration (4), for the acceleration direction see the introduction.

Figure 34, putting the fixtures.

Figure 35, adding the acceleration.

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5. Applying the material to vehicle components:

Right click on the component (1) click on apply the material (2). Finally repeat the steps that mentioned in stage one.

6. creating the connection on the assembled design:

Figure 36, applying the material for chassis components.

Figure 38, creating the contact set

Figure 37, creating the component contact.

B

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Click on connection adviser (1) than select component contact (2); check the box exactly as shown on part B in figure 33.click contact set(3), select automatic find contact set(4), select the whole chassis and click find contact set(5), and finally chose bonded than apply the changes (6).

The purpose of the two steps (contact set and component contact) is to connect all of the chassis members together, and to connect the chassis with the assembled components in order to mesh the component and getting the simulation without any error.

7. creating a mesh:

Click on create mesh under run option (1) click on curvature based mesh (2). Check draft quality mesh (3). And finally run the design.

converting the vehicle components to masses:

This is an additional step I did it to convert the vehicle component from solids to mass in order to get the results only for the chassis (for the displacement simulation only). First right click in the component (1), click on treat as remote mass (2).

Figure 39, creating a mesh.

Figure 40, vehicle components.

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Chassis Finite Element Analysis:

FEA analysis during braking: Stress analysis

Note: I suppressed all of the vehicle components. As we can see the stress is not distributed uniformly on the chassis members (the stress

range is from 0 MPa (minimum) to 203.3 MPa (maximum)); the highest stress on the chassis members is at point A which is equal to 203.3MPa. The value of this the stress is not very accurate at point A1 because there was an error in trimming the members (A2) where the value of the stress should be between 135.5MPa to 169.4MPa. This point Still exposing to high amount of stress due to at this point the bottom side member is exposing directly to the weight of the passenger. Furthermore, this point is an attachment point where it connects between three members; which this attachment point receive the stress from three members leading to stress concentration. In addition, this point is a heat affected zone, where the heat of cutting the members and welding them stresses the material causing residual stresses. In figure 41, it is obvious that the stress is higher at the rear of the car; this happened because the heaviest components are placed at the rear of the car (engine 200 Kg, each passenger 75 Kg), so the stress at the rear of the chassis members is higher than the front of the chassis members. One

Figure 41, Stresses on the chassis

A2

A1

B C

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of the biggest stresses on the chassis is at point B (one of the bottom layer members) because it expose to the weight of the engine and the weight of the left passenger. The second highest stress after point A is at point C (end point of bottom side member) where the stress concentrates more because it is an attachment point, this member carries the engine directly; therefore it get high stress from the engine weight. The location of the engine is not right where actually the engine is mounted through using brackets in the bottom layer members, top layer members and the roll cage; so the actual stress is lower at point C. In this analysis I did not include the roll cage where the roll cage is heavy component will increase the stress on the members that will be placed on them, however, adding the roll cage will increase the torsional rigidity of the chassis. I placed the engine on the bottom side members and I removed the roll cage in order to make the analysis easier. The figure below shows the stress on the side bottom members only (for every points):

Figure 42 shows the stresses on the side bottom members in all meshes (all of the points

that solid-works calculated the stress on them separately); it is obvious that there is a big

amount of variation in the total stress (Von Mises stress) for each mesh as a separate part.

Most of the total stresses are equal to approximately 10 MPa to 25 MPa; since the remaining

stresses are from 25 MPa to 95 MPa where the stress is higher at these points because either

these point are exposing the stresses of the heavy components or if they are attachments point

due to stress concentration.

Figure 42, Stresses on side bottom members

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Strain analysis:

As we can see the strain figure is similar to the stress figure, the difference is only that the

stress figure is shows stress values and strain figure shows the strain value. To explain this, the

strain is directly proportional to the stress that is exposed to. To expand, the stiffness of the

material (young modulus) is equal to the stress divided by strain

; since the young

modulus is constant for the material; thus when the stress increases the strain increases as

well. This makes the two stress and strain figure similar so l don’t need to repeat the stress

analysis. For the displacement (deflection) part; the displacement is affected by magnitude of

the stress that the member will expose to also the length of the member (based on how the

member connected and how the force is applied). For example when Appling the member to

bending stress from the middle it is the member is similar to simply supported beam, so the

highest deflection will be at the middle. The deflection of simply supported beam is

, where

W is the load in newton L is the length of the beam E is the young modulus and I is second

moment of area.

Displacement analysis:

Figure 43, strain on the whole chassis.

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As we can see, the displacement range is from approximately 0 mm to 0.6427 mm; this

means that the maximum displacement (deflection) on the chassis members is lower than the

allowable amount deflection (1 mm). From figure 44, the displacement is not equal; some of

the biggest displacements are at point A, B, C, and D; since one of the smallest displacements is

at point E. The displacement is high at point A and B because they expose to bending stress due

to the weight of the engine. Point C and D expose to higher amount of deflection than point A

and B; the deflection occurred due to the longitudinal weight transfer from the rear to the front

which causes torsion to the members C and D. The highest bending is at point Z which it

exposes to the weight passenger also the torsional force due to longitudinal weight transfer.

The deflection at point E is too small because this member does not carry any components (no

loads that act on it); expect the small effect of longitudinal weight transfer.

Figure 44, displacement on the whole chassis.

A

C

B

D

E

Z

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Figure 45, FOS during braking

A

C

B D

E

F

Z

FOS:

Point A B C D E F Z

FOS 58.8 8539.7 249.5 12.11 10300.3 177.7 1.69

As shown on figure 45, the minimum FOS on the chassis is 1.69 which is located at point Z;

we know that the amount of stress is higher than the actual; for all of the reaming parts the FOS

is higher than 2 which is the required FOS for the design (see FOS section). This mean all of the

chassis design is safe during braking except point Z that exposes to more stress, and due to the

displacement is lower than 1 mm; it is recommended to heat treat the chassis especially for

the joint like point Z in order, to minimise the stress concentration and stress relief.

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FEA analysis during Acceleration:

Stress analysis

Note: I suppressed all of the vehicle components. During acceleration the locations of the highest stresses are similar to the braking situation

because the main cause of stress concentration is the weight of the components (especially for engine and passenger loads), and the attachment points that they expose to higher stresses. During acceleration the maximum von Mises stress decreased from 203.3MPa (during braking) to 121.6 MPa.

As we can see the stress is not distributed uniformly on the chassis members (the stress range is from 0 MPa (minimum) to 121.6 MPa (maximum)); the highest stress on the chassis members is at point A which is equal to 101.3MPa. The value of this the stress is not very accurate at point A because there was an error in trimming the members where the value of the stress should be between 91.2 MPa to 169.4MPa. This point Still exposing to high amount of stress due to at this point the bottom side member is exposing directly to the weight of the passenger. Furthermore, this point is an attachment point where it connects between three members; which this attachment point receive the stress from three members leading to stress concentration. In addition, this point is a heat affected zone, where the heat of cutting the members and welding them stresses the material causing residual stresses. In figure 46, it is

Figure 46, Stresses on the chassis during acceleration.

A

D

C

B

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obvious that the stress is higher at the rear of the car; this happened because the heaviest components are placed at the rear of the car (engine 200 Kg, each passenger 75 Kg), so the stress at the rear of the chassis members is higher than the front of the chassis members. One of the biggest stresses on the chassis is at point B (one of the bottom layer side member) because it exposes to the weight of the left passenger also; it is an attachment point where it exposes to more stress from the attached members. Furthermore, point D (the side member in the bottom layer of the chassis) exposes to high amount of stress as well due to the load of the passenger that pushes this member (bend it), and the longitudinal weight transfer from front to rear that adds more load on the member (more bending stress). The second highest stress after point A is at point C (end point of bottom side member) where the stress concentrates more because it is an attachment point, this member carries the engine directly; therefore it get high stress from engine mass. The location of the engine is not right where actually the engine is mounted through using brackets in the bottom layer members, top layer members and the roll cage; so the actual stress is lower at point C. In this analysis I did not include the roll cage where the roll cage is heavy component will increase the stress on the members that will be placed on them, however, adding the roll cage will increase the torsional rigidity of the chassis. I placed the engine on the bottom side members and I removed the roll cage in order to make the analysis easier. In addition, the effect of longitudinal weight transfer due to acceleration force is not very clear in stress analysis; in displacement analysis it is clearer. The figure below shows the stress on the side bottom members only (for every points):






37 | P a g e







allowable amount deflection (1 mm). From figure 48, the displacement is not equal; the light

blue arrows shows the effect of the acceleration force where the displacement increased more

in these points, this occurred due to the longitudinal weight transfer from front to rear which

increases the stresses in these points. Some of the biggest displacements are at point A, B, C,

and D; since one of the smallest displacements is at point E. The displacement is high at point A

and B because they expose to bending stress due to the weight of the engine. Point C and D

expose to higher amount of deflection than point A and B; the deflection occurred due to the

longitudinal weight transfer from the front to the rear which causes torsion to the members C

and D. The highest bending is at point Z which it exposes to the weight of the passenger at this

Figure 48, displacement on the whole chassis (during acceleration)

A

D

B

C

E

Z

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Figure 49, FOS during acceleration

A

C

B

D

E

F

Z

point, and point Z expose to more bending force due to longitudinal weight transfer. The

deflection at point E is too small because this member does not carry any components (no

loads that act on it); expect the small effect of longitudinal weight transfer.

FOS:

Point A B C D E F Z

FOS 14.26 18.86 159.27 73.41 100.34 42.47 2.89

As shown on figure 49, the minimum FOS on the chassis is 2.89; it is located at point Z. The

minimum FOS is higher than the required FOS (2). As a consequence that the highest

displacement is lower than 1 mm, and the actual FOS is high the chassis design is safe during

acceleration. For optimising the design it is recommended adding light weight roll cage for

decreasing the stress on the chassis members, and taking into account selecting an appropriate

member (a member that is not expose to high value of stress) to mount the roll cage.

Therefore, the roll cage will assist in increasing the torsional rigidity of the chassis and helps the

passenger from roll over and side accidents.

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FEA analysis during Cornering: Stress analysis

Note: I suppressed all of the vehicle components. As we can see the stress is not distributed uniformly on the chassis members (the stress

range is from 0 MPa (minimum) to 219.2 MPa (maximum)); the highest stress on the chassis members is at point A which is equal to 219.2MPa. The value of this the stress is not very accurate at point A1 because there was an error in trimming the members (A2) where the value of the stress should be between 146.1 MPa to 164.4MPa (I discovered the new error in the cornering situation). Therefore, for future analysis I need to double check the trims, and try to fix them if possible for getting more accurate results. This point is still exposing to high amount of stress due to at this point the bottom side member is exposing directly to the weight of the engine. Furthermore, this point is an attachment point where it connects between three members; which this attachment point receive the stress from three members leading to stress concentration. In addition, this point is a heat affected zone, where the heat of cutting the members and welding them stresses the material causing residual stresses. In figure 50, it is obvious that the stress is higher at the rear of the car; this happened because the heaviest components are placed at the rear of the car (engine 200 Kg, each passenger 75 Kg), so the stresses at the rear of the chassis members are higher than the stress on the front of the chassis members.

Figure 50, Stresses on the chassis

A2 A1

B

C

D

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One of the biggest stresses on the chassis is at point B (one of the side members in the bottom layer of the chassis) because it expose to the weight of the engine and the weight of the left passenger. The second highest stress after point A is at point D than C (end points of bottom sides member) where the stress concentrates more because they are attachment points, these members carry the passengers; therefore these members get high stress from the passengers weight. Again, the stress analysis do not describe the effect of cornering force very well, I will describe the effect of lateral weight transfer in displacement section more clear.









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allowable amount deflection (1 mm). From figure 48, the displacement is not equal; the light

blue arrows shows the effect of the acceleration force where the displacement increased more

in these points, this occurred due to the lateral weight transfer from the left of the car to the

right of the car (during cornering to the left). To clarify, the light blue arrows show some of the

points that got higher displacement (deflection) after cornering to the left. Some of the biggest

displacements are at point A, B, C, and D; since one of the smallest displacements is at point E.

The displacement is high at point A and B because they expose to bending stress due to the

weight of the engine. Point A exposes to higher displacement than B due to the weight transfer

from left to right where the member at point A will experiences more load, therefore more

stress, and thus more displacement.

Point C and D expose to higher amount of deflection than point A and B; the deflection

occurred due to the lateral weight transfer from the left of the vehicle to the right of the

vehicle. To expand, point D will expose to maximum weight transfer which causes bending. For

Figure 52, displacement on the whole chassis (during acceleration)

A

D

B

C

E

Z

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Figure 53, FOS during cornering

A

C

B

D

E

F

Z

point C, it will expose higher bending force due to weight transfer and also, the member in

point C will be in torsion as well. The highest stress is at point Z, because the chassis member

(for point Z) exposes the maximum weigh transfer which led to bend the member, and the

passenger weight, therefore, point Z expose to high amount of deflection (comparing to the

reaming chassis members) due to the bending stress. The deflection at point E is too small

because this member does not carry any components (no loads that act on it); expect the small

effect of lateral weight transfer.

FOS:

Point A B C D E F Z

FOS 10.95 42.47 17.02 32.45 64.25 29.89 1.6

As shown on figure 53, the minimum FOS on the chassis is 1.6 which is located at point Z; we

know that the amount of stress is higher than the actual; for all of the reaming parts the FOS is

higher than 2 which is the required FOS for the design (see FOS section). This mean all of the

chassis design is safe during cornering except point Z that exposes to more stress, and due to

the displacement is lower than 1 mm; it is recommended to heat treat the chassis especially

for the joint like point Z in order, to minimise the stress concentration and stress relief.

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Figure 54, welding machine (hotrod, 2010)

Method of joining:

Two or more materials can be joined through using various methods based on the required

type of joint to be permanent or semi-permanent. In permanent joints; the joint cannot be

reserved without damaging the material. Since, in semi-permanent joints are designed to be

permanent, but the joints can be disassembled without damaging the materials. (Method Of

Joining Materials, 2012)

Welding:

The main method for joining the metals permanently is by welding. There are several types

of welding for instance, MIG welding, TIG welding, electric arc welding, oxyacetylene welding,

seam welding, etc. All these types of welding use the heat for joining the metals permanently;

leading to the two main pieces of the metal to be molten, and using a joining material for

mixing them before solidifying. This generates a strong permanent joint. One advantage of

welding that it can be repetitive due to robots can be used in welding especially when mass

production is required such as, for car industries. (siliconfareast, 2005)

During welding process; the temperature of the welding leads to change the microstructure

of the welded areas of the working pieces. These areas are defined as, heat affected zone (HAZ)

where the tensile strength and toughness of the metal decreases. A residual stresses which

grow as the metal cools down and decrease the strength of the welded joints. Therefore, the

welding process must be improved to decrease the microstructural changes, and the residual

stresses in the welded area. Post welding treatments are used to relieve the residual stresses,

and to make the microstructure of the welds more uniform (see Post welding heat treatment

section). (Method Of Joining Materials, 2012)

A. MIG Welding:

MIG welding is a short for Metal Inert Gas welding; it

combines two pieces of metal together with a consumable

wire that is connected to an electrode current. The wire

passes through the welding gun in the same time of the

inert gas. The purpose of the inert gas is protecting the

electrode from contaminants. (TIG vs. MIG Welding - What's

the Difference?, n.d.)

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Figure 55, MIG and TIG welding (mechanical-engineering, 2011)

Advantages:

The quickness; it is fast in producing the welds.

Inexpensive price and the Equipment is more accessible.

User friendly; because the welds are easier to make than TIG welding, and the step takes

less time and is easy to automate than TIG welding.

Disadvantages:

Generates big amount of sparks, smoke and fume during the welding process.

Reliability; possible irregular wire feedback and burn-back may occur with MIG welding.

B. TIG Welding:

TIG welding is a short for as Tungsten inert gas welding; it uses non-consumable tungsten,

along with an inert gas, in order to weld two pieces of metal together. The purpose of tungsten

electrode is providing the electricity for the welding process not for the filler.

Advantages:

TIG welding produce lower amount of sparks, fumes and smoke than MIG welding.

Provides more precise, and higher quality welds than TIG.

Autogenous Welds do not need a filler material to where TIG welding creates a weld

through melting one part to the other. Furthermore, Autogenous welds are typically used

during welding thinner materials.

Disadvantages:

Not user friendly where TIG welding needs more setup time.

More expensive and takes more time thicker metals than MIG welding Specifically during

welding

TIG welding is complicated and needs more skills than the MIG welding.

http://www.used-robots.com/applications/tig-welding

http://www.used-robots.com/applications/tig-welding

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Figure 56, Brazing (Brazing practice, 2013)

Brazing

The third joining process is brazing where it is used to join two work pieces together

through using a filler metal that is sandwiched between them, and the filler metal undergoes

melting only which the two work pieces do not face any melting. Thus, the temperature that

the brazing process can be done must be high enough to melt the filler material. Furthermore,

the materials that are used as fillers for the brazing process are those that melt above . In

addition, a flux is used as well during brazing process for eliminating the oxide films from the

surfaces of the work pieces and preventing oxidation. This ensures a good metallurgical bond

among the work pieces, and the filler until the brazing process is done. There are many

advantages for brazing joining method for example; they make the joining zones attractive. In

addition, the brazed joint offers strength equal to or higher than the work pieces itself. The

brazed joints are ductile, so they can withstand a considerable vibrations and shocks. Also, the

brazing is done at low temperatures; this reduces the possibility of warping and overheating or

melting the metals that will be joined. However, the brazing method of joining that close fit

tolerances are required. (Is Brazing Better?, 2005)

Soldering:

The forth method of joining the metals is soldering; during soldering process two work

pieces of metal are joined together by a third metal called (solder or filler) at a relatively low

temperature that is higher the melting point of the filler. Soldering is classified within two

types; the first type is hard soldering where the lowest melting point in hard soldering is ,

and the second type is soft soldering where the melting point is approximately . The

stages in soldering process are:

1. First clean and degrease the materials; and the materials can be kept clean through using a

flux.

2. The surfaces of the materials must be filled together without any gap.

3. A heat source like a blow torch should be used to heat the materials between the joint in

order to ensure that both pieces are uniformly heated.

4. After completing the joints should be left to cool and harden.

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Figure 57, Gas blow torch (directindustry, 2011)

Advantages:

Requires lower power.

Low joining temperature.

Dissimilar materials can be joined together.

There are no residual stresses in the joint parts.

User friendly; easily automated joining process.

Microstructure is not affected by heat of soldering.

Disadvantages:

Requires careful removal of the flux residuals to prevent corrosion.

Cannot be used for joining large sections.

Cannot be used for joining in high temperature applications. (tech, n.d.)

Selection of method of joining:

All of the previous mentioned methods are about permanent joining methods, however,

there is many other Simi-permanent method of joining such as using nuts and bolts for joining;

since the permanent joining method is stronger and we do not need to disassemble the chassis.

Therefore, I will choose a type of permanent joining method. The available permanent joining

method at building 30 is welding (MIG welding and TIG welding); thus I will make the

comparison between the two types only

Decision matrix (for choosing the type of welding that is available at building 30):

Factor Cost Safety User friendly

Total Mark: Mark: 7 Mark: 7 Mark: 10

Requirements Less in cost Safe welding method Easy to use

MIG welding 7*7 4*7 9*10 167

TIG welding 5*7 6*7 6*10 137 Table 4, decision matrix

Due to, the MIG welding is faster, easier where it do not requires skilled hand for doing it,

also, it is cheaper than TIG welding and the equipment is more accessible I will choose MIG

welding for welding the members of the chassis.

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Figure 58, welding structure parts (section view) (BASIC WELDING, n.d.)

Heat treatment: As mentioned previously; the stress concentrates more on the attachment points; these

attachments points are located at the heat affected zones where the welding stresses the

material (residual stress). The figure below categories the parts of weldment structure where it

consist of fusion zone (weld metal), fusion boundary , Heat affected zone and

the unaffected base metal . (BASIC WELDING, n.d.). Basically, the heat affected zone

is a portion of the base metal that has not reached to the melting point, however the

material mechanical properties or the microstructure (crystalline structure) have been altered

from the heat of welding and cutting. Thus the material in the heat affected zone is stressed,

and the material hardness increases (becomes brittle)). (PWHT Determines the Quality of

Weldments, 2012). Furthermore, the stress concentration occurs due to a crack on the welding

area generated due to a defect during welding which lead to the stress concentration on the

welding points.

Post weld heat treatment (PWHT) (Stress relieving):

Typically stress relieving is applied for carbon and low alloy steels where the metal

temperature is raised to be just below than the transformation temperature, and held for a

prescribed time and allowed to cool at a controlled rate. It is a process of uniform heating of a

structure to a suitable temperature, holding at this temperature for predetermined period of

time, followed by a uniform cooling where an even cooling may causes an extra stresses. The

aim of this process is to eliminate the residual stress in metals, reduce the hardness of the weld

and adjacent the heat affected zone after welding to recover the acceptable limits; therefore,

reducing the possibility of cracking. Thus the benefits of stress relieving are: (Khan, 2007)

Relieve the welding residual stresses (the main purpose).

Decrease the hardness of the heat-affected zone.

Improve ductility and notch toughness.

Release the diffusible hydrogen.

On the other hand, the extended heating could reduce the tensile strength and notch

toughness of the welds. (PWHT Determines the Quality of Weldments, 2012)

48 | P a g e

Figure 60, Residual stress versus reliving temperature

The percentage of relief of internal stress is based on the steel type (the material yield

strength), the heating rate, soaking temperature and period, the cooling rate, and the

temperature difference in the weldment during the heating and cooling cycle. The most

important factors for stress relieving rate and the quality of the weld are soaking temperature

and time. The more heat is the more stress relieve, and the more time is the more stress relive

as shown on the figure below (an example of 2.25Cr-lMo steel welds); this rule is not applied to

the curve A because the material was exposed to a high amount of heat for long time which led

to increase the stress again. In addition, to ensure a uniform temperature distribution and to

minimize the thermal stress; the maximum heating and cooling rates and the maximum

temperature difference are to be determined before starting the process. (Funderburk, 1998)

The figure above shows the average stress remaining (residual stress) versus reliving

temperature for three different materials with different yield strength 70000 psi (482MPa),

Figure 59, Residual stress versus soaking time (PWHT Determines the Quality of Weldments, 2012)

A

49 | P a g e

50000 psi (345MPa) and 30000 psi (207 MPa). It’s obvious that the average stress remaining is

higher in the material with higher yield stress. The figure below shows the soaking temperature

for different materials (for carbon steel is from ):

Figure 61, typical thermal treatments for weldment. (Khan, 2007)

50 | P a g e

Conclusion and future recommendations (optimization):

To conclude, the design of the chassis was successfully simulated and analysed through using

Finite element analysis feature in solid-works software. The minimum actual FOS during braking

is 1.89 (lower than the required which is 2), and the maximum amount of deflection is

0.643mm (lower than the maximum allowable deflection which is 1 mm), and the maximum

von Mises stress is 203.3MPa. The minimum actual FOS during acceleration is 2.89 (higher than

the required which is 2), and the maximum amount of deflection is 0.612mm (lower than the

maximum allowable deflection which is 1 mm), and the maximum von Mises stress is

121.6MPa. The minimum actual FOS during cornering is 1.6 (lower than the required which is

2), and the maximum amount of deflection is 0.682mm (lower than the maximum allowable

deflection which is 1 mm), and the maximum von Mises stress is 219.2MPa.

The difference between the values of FOS, stress and displacement happened as a result of

weight transfer which is longitudinal weight transfer during accelerating and braking, and

lateral weight transfer during cornering where the weight transfer adds more stresses on

different members based on the situation. For both acceleration and cornering situations the

FOS is higher than 2 expect some points (the FOS is lower than 2); this happened due to stress

concentration in the attachment points where they expose to higher stress from the attached

members, and they are heat effected zones where the heat of welding and cutting the material

stresses the material and causes residual stress.

For optimising the design it is recommended to heat treat the chassis In order to minimise

the stress concentration and the residual stress through using post weld heat treatment

method. It is recommended also adding light weight roll cage for decreasing the stress on the

chassis members, and taking into account selecting an appropriate member (a member that is

not expose to high value of stress) to mount the roll cage. Therefore, the roll cage will assist in

increasing the torsional rigidity of the chassis and helps the passenger from roll over and side

accidents.

51 | P a g e

Appendix (A)

Figure 62, finding the chassis mass in KG through using solid work software.

52 | P a g e

Appendix (B)

Figure 63, creep test device. (CREEP TESTING MACHINE, n.d.)

Figure 64, tensile test device. (matcsi, 2010)

53 | P a g e

Appendix (C)

Figure 65, failure theory (Failure Mechanics, 2013)

Figure 66, failure theory (Failure Criteria, 2013)

54 | P a g e

Appendix (D)

(Solid-Works study)

Model Information

Model name: Assem4

Current Configuration: Default

Solid Bodies

Document Name and Reference

Treated As Volumetric Properties Document Path/Date

Modified

Structural Member2[38]

Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3

Density:2700 kg/m^3 Weight:1.39932 N

C:\Users\Ya7ya\Videos\alaysis final\chassisn today\21-5\Chassis analysis\Chassis

analysis new template.SLDPRT

May 21 16:00:02 2014

55 | P a g e

Trim/Extend27[1]

Solid Body

Mass:0.500985 kg Volume:0.00018555 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014

Trim/Extend26[1]

Solid Body

Mass:0.104734 kg Volume:3.87905e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.730554 kg Volume:0.000270576 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014

Trim/Extend69

Solid Body

Mass:0.24479 kg Volume:9.06631e-005 m^3




May 21 16:00:02 2014

56 | P a g e

Trim/Extend73

Solid Body

Mass:0.192735 kg Volume:7.13832e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014

Trim/Extend66

Solid Body

Mass:0.0900621 kg Volume:3.33563e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.713938 kg Volume:0.000264421 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.363616 kg Volume:0.000134673 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.713938 kg Volume:0.000264421 m^3




May 21 16:00:02 2014

57 | P a g e


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014

Trim/Extend83

Solid Body

Mass:0.500985 kg Volume:0.00018555 m^3




May 21 16:00:02 2014

Trim/Extend64

Solid Body

Mass:0.0925187 kg Volume:3.42662e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014

Trim/Extend98

Solid Body

Mass:0.26034 kg Volume:9.64223e-005 m^3




May 21 16:00:02 2014

Trim/Extend109

Solid Body

Mass:0.250406 kg Volume:9.27429e-005 m^3




May 21 16:00:02 2014

Trim/Extend80

Solid Body

Mass:0.54274 kg Volume:0.000201015 m^3




May 21 16:00:02 2014

58 | P a g e

Trim/Extend23[1]

Solid Body

Mass:0.713938 kg Volume:0.000264421 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.51138 kg Volume:0.0001894 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.511387 kg Volume:0.000189403 m^3




May 21 16:00:02 2014

Trim/Extend10[6]

Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.363611 kg Volume:0.000134671 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.461558 kg Volume:0.000170948 m^3




May 21 16:00:02 2014

59 | P a g e


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.461558 kg Volume:0.000170948 m^3




May 21 16:00:02 2014

Trim/Extend110

Solid Body

Mass:0.250406 kg Volume:9.27429e-005 m^3




May 21 16:00:02 2014

Trim/Extend86

Solid Body

Mass:0.411776 kg Volume:0.00015251 m^3




May 21 16:00:02 2014

Trim/Extend10[8]

Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014

Trim/Extend27[2]

Solid Body

Mass:0.500985 kg Volume:0.00018555 m^3




May 21 16:00:02 2014

Trim/Extend85

Solid Body

Mass:0.535741 kg Volume:0.000198423 m^3




May 21 16:00:02 2014

60 | P a g e


Solid Body

Mass:0.713921 kg Volume:0.000264415 m^3




May 21 16:00:02 2014

Trim/Extend88

Solid Body

Mass:0.749248 kg Volume:0.000277499 m^3




May 21 16:00:02 2014

Trim/Extend10[1]

Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014

Trim/Extend67

Solid Body

Mass:0.0925187 kg Volume:3.42662e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.692355 kg Volume:0.000256428 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.363611 kg Volume:0.000134671 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014

61 | P a g e


Solid Body

Mass:0.363616 kg Volume:0.000134673 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.692355 kg Volume:0.000256428 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014

Trim/Extend89

Solid Body

Mass:0.175529 kg Volume:6.50108e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.730554 kg Volume:0.000270576 m^3




May 21 16:00:02 2014

Trim/Extend82

Solid Body

Mass:0.528305 kg Volume:0.000195668 m^3




May 21 16:00:02 2014

Trim/Extend97

Solid Body

Mass:0.260342 kg Volume:9.64231e-005 m^3




May 21 16:00:02 2014

62 | P a g e


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014

Trim/Extend10[3]

Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014

Trim/Extend10[10]

Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014

Trim/Extend26[2]

Solid Body

Mass:0.0587917 kg Volume:2.17747e-005 m^3




May 21 16:00:02 2014

Trim/Extend65

Solid Body

Mass:0.0902453 kg Volume:3.34242e-005 m^3




May 21 16:00:02 2014

Trim/Extend76

Solid Body

Mass:0.244756 kg Volume:9.06504e-005 m^3




May 21 16:00:02 2014

63 | P a g e

Trim/Extend72

Solid Body

Mass:0.192735 kg Volume:7.13832e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.730554 kg Volume:0.000270576 m^3




May 21 16:00:02 2014

Trim/Extend21[2]

Solid Body

Mass:0.461569 kg Volume:0.000170952 m^3




May 21 16:00:02 2014

Trim/Extend10[5]

Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.51138 kg Volume:0.0001894 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014

64 | P a g e

Trim/Extend24[4]

Solid Body

Mass:0.713938 kg Volume:0.000264421 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.692365 kg Volume:0.000256431 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.478172 kg Volume:0.000177101 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.730554 kg Volume:0.000270576 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.511387 kg Volume:0.000189403 m^3




May 21 16:00:02 2014

Trim/Extend25[2]

Solid Body

Mass:0.713928 kg Volume:0.000264418 m^3




May 21 16:00:02 2014

Trim/Extend90

Solid Body

Mass:0.175528 kg Volume:6.50105e-005 m^3




May 21 16:00:02 2014

65 | P a g e


Solid Body

Mass:0.478181 kg Volume:0.000177104 m^3




May 21 16:00:02 2014

Trim/Extend21[3]

Solid Body

Mass:0.461569 kg Volume:0.000170952 m^3




May 21 16:00:02 2014

Trim/Extend87

Solid Body

Mass:0.41178 kg Volume:0.000152511 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.478172 kg Volume:0.000177101 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.478181 kg Volume:0.000177104 m^3




May 21 16:00:02 2014

Trim/Extend79

Solid Body

Mass:0.752804 kg Volume:0.000278816 m^3




May 21 16:00:02 2014

Trim/Extend84

Solid Body

Mass:0.494467 kg Volume:0.000183136 m^3




May 21 16:00:02 2014

66 | P a g e


Solid Body

Mass:0.692365 kg Volume:0.000256431 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.478172 kg Volume:0.000177101 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.478172 kg Volume:0.000177101 m^3




May 21 16:00:02 2014

Trim/Extend81

Solid Body

Mass:0.542741 kg Volume:0.000201015 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014


Solid Body

Mass:0.142788 kg Volume:5.28843e-005 m^3




May 21 16:00:02 2014

67 | P a g e

Study Properties Study name Acceleration

Analysis type Static

Mesh type Solid Mesh

Thermal Effect: On

Thermal option Include temperature loads

Zero strain temperature 298 Kelvin

Include fluid pressure effects from SolidWorks Flow Simulation

Off

Solver type Direct sparse solver

Inplane Effect: Off

Soft Spring: Off

Inertial Relief: Off

Incompatible bonding options Automatic

Large displacement Off

Compute free body forces On

Friction Off

Use Adaptive Method: Off

Result folder SolidWorks document (C:\Users\Ya7ya\Videos\alaysis final\chassisn

today\21-5\Chassis analysis)

Units Unit system: SI (MKS)

Length/Displacement mm

Temperature Kelvin

Angular velocity Rad/sec

Pressure/Stress N/mm^2 (MPa)

68 | P a g e

Material Properties

Model Reference Properties Components

Name: 1350 Alloy Model type: Linear Elastic Isotropic

Default failure criterion: Max von Mises Stress Yield strength: 27.5742 N/mm^2

Tensile strength: 82.7227 N/mm^2 Elastic modulus: 69000 N/mm^2 Poisson's ratio: 0.33 Mass density: 2700 g/cm^3

Shear modulus: 27000 N/mm^2 Thermal expansion

coefficient: 2.4e-005 /Kelvin

SolidBody 1(Boss-

Extrude1)(Battery-2),

SolidBody 1(Structural Member2[38])(Chassis

analysis new template-1), SolidBody

2(Trim/Extend27[1])(Cha

ssis analysis new template-1),



4(Trim/Extend26[1])(Cha

ssis analysis new template-1),


analysis new template-1),


analysis new template-1), SolidBody 7(Structural

Member2[48])(Chassis analysis new template-1),

SolidBody

8(Trim/Extend69)(Chassis analysis new template-

1), SolidBody

9(Trim/Extend73)(Chassi

s analysis new template-1),



SolidBody 11(Trim/Extend66)(Chass

is analysis new template-1),





69 | P a g e

Member2[11])(Chassis







18(Trim/Extend83)(Chass




SolidBody 20(Structural



is analysis new template-

1), SolidBody

22(Trim/Extend109)(Chassis analysis new

template-1), SolidBody



SolidBody 24(Trim/Extend23[1])(Ch

assis analysis new

template-1), SolidBody 25(Structural





assis analysis new template-1),




70 | P a g e










34(Trim/Extend110)(Chassis analysis new





assis analysis new


37(Trim/Extend27[2])(Chassis analysis new








SolidBody




1),



71 | P a g e
















1), SolidBody


1), SolidBody 53(Structural




SolidBody







58(Trim/Extend26[2])(Ch


SolidBody

72 | P a g e





SolidBody



Member2[2])(Chassis











SolidBody



Member2[3])(Chassis









SolidBody

73 | P a g e















SolidBody















analysis new template-1), SolidBody 1(Boss-

Extrude1)(Driver-1),

74 | P a g e

SolidBody 1(Boss-

Extrude1)(Driver-2), SolidBody 1(Boss-

Extrude1)(Engine-2), SolidBody 1(Boss-

Extrude1)(Fuel Tant-5), SolidBody 1(Boss-

Extrude1)(Radiator-1),

SolidBody 1(Boss-Extrude1)@Battery-2,

SolidBody 1(Boss-Extrude1)@Driver-1,

SolidBody 1(Boss-

Extrude1)@Fuel Tant-5, SolidBody 1(Boss-

Extrude1)@Driver-2, SolidBody 1(Boss-

Extrude1)@Engine-2, SolidBody 1(Boss-

Extrude1)@Radiator-1

Curve Data:N/A

75 | P a g e

Loads and Fixtures

Fixture name Fixture Image Fixture Details

Fixed-1

Entities: 8 face(s) Type: Fixed Geometry

Resultant Forces Components X Y Z Resultant

Reaction force(N) -5751.75 6397.36 -0.000268936 8602.84

Reaction Moment(N·m) 0 0 0 0

Load name Load Image Load Details

Gravity-1

Reference: Top Plane Values: 8.82 -0 -9.81 Units: SI

SolidBody 1(Boss-

Extrude1)@Battery-2

Name: Boss-Extrude1 Remote Mass: 4.32 kg

Moment of Inertia: 0.0288,0.014976,0.014976,7.71196e-018,8.30267e-

020,1.37655e-019 kg·m^2

SolidBody 1(Boss-

Extrude1)@Driver-1


Moment of Inertia: 6.63447,6.08175,9.49647,-1.25799e-016,3.61658e-

016,2.06725e-016 kg·m^2

76 | P a g e

SolidBody 1(Boss-

Extrude1)@Fuel Tant-5


Moment of Inertia: 0.0153527,0.263934,0.263934,1.4747e-017,-9.41132e-019,3.36763e-017 kg·m^2

SolidBody 1(Boss-

Extrude1)@Driver-2


Moment of Inertia: 6.63447,6.08175,9.49647,9.05805e-018,-4.30515e-

016,7.49137e-016 kg·m^2

SolidBody 1(Boss-

Extrude1)@Engine-2


Moment of Inertia: 4.39453,7.03125,4.39453,-1.27674e-016,6.21733e-

018,5.19511e-016 kg·m^2

SolidBody 1(Boss-

Extrude1)@Radiator-1


Moment of Inertia: 0.121306,0.0847008,0.0380448,1.43655e-017,2.87124e-

017,-2.208e-011 kg·m^2

Connector Definitions No Data

77 | P a g e

Contact Information

Contact Contact Image Contact Properties

Contact Set-3

Type: No Penetration contact pair

Entites: 2 face(s) Advanced: Surface to

surface

Global Contact

Type: Bonded Components: 1 component(s)

Options: Incompatible mesh

78 | P a g e

Mesh Information Mesh type Solid Mesh

Mesher Used: Curvature based mesh

Jacobian points 4 Points

Maximum element size 0.114902 m

Minimum element size 0.0229805 m

Mesh Quality Draft Quality Mesh

Remesh failed parts with incompatible mesh On

Mesh Information - Details

Total Nodes 67077

Total Elements 209751

Maximum Aspect Ratio 153.15

% of elements with Aspect Ratio < 3 0.411

% of elements with Aspect Ratio > 10 39.8

Time to complete mesh(hh;mm;ss): 00:00:45

Computer name: YA7YA-PC

79 | P a g e

Sensor Details No Data

Resultant Forces

Reaction Forces Selection set Units Sum X Sum Y Sum Z Resultant

Entire Model N -5751.75 6397.36 -0.000268936 8602.84

Reaction Moments Selection set Units Sum X Sum Y Sum Z Resultant

Entire Model N·m 0 0 0 0

Beams No Data

80 | P a g e

Study Results

Name Type Min Max Stress1 VON: von Mises Stress 0.000883516 N/mm^2

(MPa) Node: 60047

118.688 N/mm^2 (MPa)

Node: 66108

Assem4-Acceleration-Stress-Stress1

Name Type Min Max Displacement1 URES: Resultant Displacement 0 mm

Node: 11105 1.70957 mm Node: 38937

81 | P a g e

Assem4-Acceleration-Displacement-Displacement1

Name Type Min Max Strain1 ESTRN: Equivalent Strain 2.5824e-008

Element: 188604 0.003049

Element: 207497

82 | P a g e

Assem4-Acceleration-Strain-Strain1

Name Type Min Max Factor of Safety1 Automatic 0.232324

Node: 66108 31209.6

Node: 60047

Assem4-Acceleration-Factor of Safety-Factor of Safety1

Name Type Displacement1{1} Deformed Shape

83 | P a g e

Assem4-Acceleration-Displacement-Displacement1{1}

84 | P a g e

Reference: BASIC WELDING. (n.d.). Retrieved from

http://www.gcs.k12.nc.us/cms/lib05/NC01000806/Centricity/Domain/524/ArcWeldingBasics.pptx

Brazing practice. (2013). Retrieved from Brazing practice:

http://upload.wikimedia.org/wikipedia/commons/6/6b/Brazing_practice.jpg Cambridge), B. C. (2014). cantilever beam. Retrieved from doitpoms:

http://www.doitpoms.ac.uk/tlplib/thermal-expansion/printall.php directindustry. (2011). Retrieved from directindustry: http://img.directindustry.com/images_di/photo-

g/gas-blow-torches-108305-3418019.jpg ductile and brittle fracture. (2008). Retrieved from sv.vt:

http://www.sv.vt.edu/classes/MSE2094_NoteBook/97ClassProj/exper/bailey/www/bailey.html Ductile Fracture 2. (2013). Retrieved from hsctut:

http://www.hsctut.materials.unsw.edu.au/Crack%20Theory/cracktheory2b.htm# Duralumin. (2013). Retrieved from spaceflight:

http://www.spaceflight.esa.int/impress/text/education/Images/MechanicalProperties/Image007.png

fatigue. (n.d.). Retrieved from marinediesels:

http://www.marinediesels.info/2_stroke_engine_parts/Other_info/fatigue.htm Funderburk, R. S. (1998). Key Concepts in Welding Engineering. Retrieved from jflf:

http://www.jflf.org/pdfs/papers/keyconcepts4.pdf Harbin, W. (2013, September 24). vehicle load transfer. Retrieved from slideshare:

http://www.slideshare.net/billharbin/vehicle-load-transfer-parts-iiimar13 hotrod. (2010). Retrieved from hotrod: http://stblogs.hotrod.com/files/2011/03/Eastwoods-TIG-200-

DIY-TIG-Welder-623x597.jpg Introduction to Finite Element Analysis. (2008). Retrieved from sv:

http://www.sv.vt.edu/classes/MSE2094_NoteBook/97ClassProj/num/widas/history.html Is Brazing Better? (2005). Retrieved from assemblymag: http://www.assemblymag.com/articles/83151-

is-brazing-better Khan, M. (2007). Welding Science and Technology. New Delhi: New Age International (P). mechanical-engineering. (2011). Retrieved from mechanical-engineering: http://mechanical-

engineering.in/forum/uploads/blog-0068290001380538246.jpg

85 | P a g e

Method Of Joining Materials. (2012). Retrieved from rewardinglearning: http://www.rewardinglearning.org.uk/common/includes/microsite_doc_link.aspx?docid=10363-1

Pedalarm Bruch. (2005). Retrieved from wikipedia:

https://en.wikipedia.org/wiki/File:Pedalarm_Bruch.jpg PWHT Determines the Quality of Weldments. (2012). Retrieved from kobelco: http://www.kobelco-

welding.jp/education-center/abc/ABC_2001-02.html sciepub. (n.d.). fig13. Retrieved from sciepub: http://pubs.sciepub.com/ajme/1/7/24/image/fig13.png siliconfareast. (2005). joining processes. Retrieved from siliconfareast:

http://www.siliconfareast.com/joining-processes.htm Suranaree University of Technology. (2007, may). Creep and stress rupture. Retrieved from sut:

http://eng.sut.ac.th/metal/images/stories/pdf/13_Creep_and_stress_rupture.pdf tech. (n.d.). Retrieved from tech: http://www.tech.plym.ac.uk/sme/mech330/join1.htm TIG vs. MIG Welding - What's the Difference? (n.d.). Retrieved from used robots: http://www.used-

robots.com/articles/viewing/tig-vs-mig-welding-what-s-the-difference Timber deflection. (N.d.). Retrieved from roymech:

http://www.roymech.co.uk/images/Timber_deflection.gif

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