Post on 12-Apr-2015
description
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
i
ASSIGNMENT
Module Code MMD513
Module Name Machinery design - 1
Course M.Sc [Engg] in Machinery design
Department Mechanical & Manufacturing Engineering.
Name of the Student Prabhakar.P
Reg. No BAB0911001
Batch Full-Time 2011.
Module Leader Asst.Prof.Balappa.B.U
PO
STG
RA
DU
ATE
EN
GIN
EER
ING
AN
D M
AN
AG
EM
EN
T P
RO
GR
AM
ME –
(P
EM
P)
M.S.Ramaiah School of Advanced Studies
Postgraduate Engineering and Management Programmes(PEMP)
#470-P Peenya Industrial Area, 4th Phase, Peenya, Bengaluru-560 058
Machinery design -1
ii
Declaration Sheet
Student Name Prabhakar.P
Reg. No BAB0911001
Course Machinery design Batch Full-Time 2011.
Batch FT-11
Module Code MMD513
Module Title Machinery design -1
Module Date 09/07/2012 to 04/08/2012
Module Leader Asst. Prof. Balappa.B.U
Extension requests:
Extensions can only be granted by the Head of the Department in consultation with the module leader.
Extensions granted by any other person will not be accepted and hence the assignment will incur a penalty.
Extensions MUST be requested by using the ‘Extension Request Form’, which is available with the ARO.
A copy of the extension approval must be attached to the assignment submitted.
Penalty for late submission
Unless you have submitted proof of mitigating circumstances or have been granted an extension, the
penalties for a late submission of an assignment shall be as follows:
• Up to one week late: Penalty of 5 marks
• One-Two weeks late: Penalty of 10 marks
• More than Two weeks late: Fail - 0% recorded (F)
All late assignments: must be submitted to Academic Records Office (ARO). It is your responsibility to
ensure that the receipt of a late assignment is recorded in the ARO. If an extension was agreed, the
authorization should be submitted to ARO during the submission of assignment.
To ensure assignment reports are written concisely, the length should be restricted to a limit indicated in
the assignment problem statement. Assignment reports greater than this length may incur a penalty of
one grade (5 marks). Each delegate is required to retain a copy of the assignment report.
Declaration
The assignment submitted herewith is a result of my own investigations and that I have conformed to the
guidelines against plagiarism as laid out in the PEMP Student Handbook. All sections of the text and results,
which have been obtained from other sources, are fully referenced. I understand that cheating and plagiarism
constitute a breach of University regulations and will be dealt with accordingly.
Signature of the student Date
Submission date stamp (by ARO)
Signature of the Module Leader and date Signature of Head of the Department and date
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
iii
Abstract
____________________________________________________________________________
In presents days the manufacturing in the industries are changed, in order to competite
in market the manufacturing methods are changed as per the customer requirements. For which
all most all the industries deviated from the standard machines and started using special
purpose machines and CNC machines and even in the construction and agricultural field the
various machineries are developed in order to reduce the human effort. The module machinery
design-1 covers the idea of building up the mechanism by considering the various output
requirements of the machine using the standard machine elements like gears, pulleys, shafts etc
with design calculations.
In this assignment Part-A debate is on design consideration by mechanical designer
while designing the mechanical structures, were under four sub topics showing the various
design consideration such mechanical strength, optimization and aesthetic by analyzing the
given sub topic with the suitable case study the debate is presented.
In the Part-B the physical dimensions of backhoe is taken from the excavator and
modeled in CATIA v5 R16 software and the kinematic analysis is carried out using the
ADAMS software, in which the angular velocity and angular accelerations were found in the
pin joints of the backhoe. The basic calculations and comparison of the various link lengths
obtained from the calculation and actual link lengths are shown. The free body diagram of the
backhoe showing the forces acting at the various parts after lifting the mass 1m above the
ground level.
In the Part-C assignment FEA analysis is carried out were initially the model is meshed
using the Hyper mesh 2009 software by assigning the boundary conditions, material properties
and element types etc. the input from the hypermesh is taken to ANSYS 12.1 and the results of
displacement sum vector and vonmises stress is found the analysis is carried out with bucket
alone, boom and stick alone and whole backhoe assembly together. Then without
compromising the strength the shape modification is done to the stick and the boom part, the
modified parts were meshed using hypermesh and again the results were obtained from the
ANSYS and comparison of the results are shown.
Machinery design -1
iv
Contents
____________________________________________________________________________
Contents
Declaration Sheet .......................................................................................................................... ii
Abstract ........................................................................................................................................ iii
Contents ....................................................................................................................................... iv
List of Tables ............................................................................................................................... vi
List of Figures ............................................................................................................................. vii
List of Symbols ............................................................................................................................ ix
1.0 Introduction: ......................................................................................................................... 10
1.1 Mechanical strength, design optimization and aesthetic [1],[2] & [3]: ................................ 10
1.2 Mechanical strength and design optimization [4] & [5]: ...................................................... 11
1.3 Mechanical strength [6]: ....................................................................................................... 11
1.5 Conclusion: ........................................................................................................................... 12
2.0 Introduction: ......................................................................................................................... 13
2.1 Backhoe portion: .................................................................................................................. 13
2.1.1 Degrees of freedom of backhoe: ........................................................................................ 14
2.2 The materials used in backhoe: ............................................................................................ 14
2.3 Calculating bucket capacity calculation: .............................................................................. 15
2.3.1Calculating digging force calculation: ................................................................................ 16
2.3.2 Stick and arm length calculation: ...................................................................................... 17
2.3.3 Assumptions made in calculation: ..................................................................................... 17
2.3.4 Idealized cross section of stick: ......................................................................................... 18
2.3.5 Finding the length using bending equation: ...................................................................... 18
2.3.6 Idealized cross section of Boom: ....................................................................................... 19
2.3.7 Finding the length using bending equation: ...................................................................... 20
2.3.8 Finding the pin diameter using bending equation: ............................................................ 21
2.4 Free body diagram of Backhoe: ............................................................................................ 21
2.4.1 Kinematic analysis in ADAMS: ........................................................................................ 22
2.4.2 The reach diagram obtained in ADAMS: .......................................................................... 23
2.5 Range graph of backhoe: ...................................................................................................... 23
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
v
2.6 Velocity and acceleration results of backhoe: ...................................................................... 24
2.6.1 Result of angular velocity graph at bucket hinge: ............................................................. 24
2.6.2 Result of angular acceleration graph at bucket hinge: ....................................................... 25
2.6.3 Result of angular velocity graph at stick hinge: ................................................................ 26
2.6.4 Result of angular acceleration graph at stick hinge: .......................................................... 26
2.6.5 Result of angular velocity graph at Boom hinge: .............................................................. 27
2.6.6 Result of angular acceleration graph at Boom hinge: ........................................................ 28
2.7 Modeling of Backhoe in CATIA: ......................................................................................... 29
3.0 Introduction: ......................................................................................................................... 31
3.1 Finite element model conversion: ......................................................................................... 31
3.1.1 Bucket: ............................................................................................................................... 32
3.1.2 Boom and stick: ................................................................................................................. 33
3.1.3 Backhoe assembly: ............................................................................................................ 33
3.2 Boundary conditions used for analysis: ................................................................................ 35
3.2.1 Boundary conditions and load analysis of bucket: ............................................................ 35
3.2.2 The Displacement of the bucket: ....................................................................................... 35
3.2.3 Vonmises stress in the bucket: ........................................................................................... 36
3.2.4 Boundary conditions and load analysis of Stick and boom: .............................................. 36
3.2.5 The Displacement of the boom and stick: ......................................................................... 37
3.2.6 Vonmises stress in the stick and boom: ............................................................................. 38
3.2.7 Boundary conditions and load analysis of backhoe assembly: .......................................... 39
3.2.8 The Displacement of the backhoe assembly: .................................................................... 39
3.2.9 Vonmises stress in the stick and boom: ............................................................................. 40
3.3 Improving the asthetic without compromising the strength: ................................................ 41
3.3.1 Modification in Boom: ...................................................................................................... 41
3.3.2 Modification in stick: ........................................................................................................ 42
3.4 Result validation after optimisation of structure: ................................................................. 43
3.4.1 Displacement result comparison: ....................................................................................... 43
3.4.2 Vonmises Stress result comparison: .................................................................................. 44
Learning outcomes: .................................................................................................................... 45
References .................................................................................................................................. 46
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
vi
Appendex-1 ................................................................................................................................ 47
[Elemental results of hyper mesh]
Appendex-2 ................................................................................................................................ 52
[Line diagram of Backhoe assembly]
List of Tables
____________________________________________________________________________
Table No. Title of the table Pg.No.
Table 1. 1 Drill bit parameters ............................................................................................... 10
Table 1. 2 Results of comparison of TiN & HSS dry drill performance ............................... 10
Table 2. 1 Showing materials used in Backhoe assembly ..................................................... 15
Table 3. 1 Element characteristics of Bucket ......................................................................... 32
Table 3. 2 Element characteristics of Boom and Stick ........................................................... 33
Table 3. 3 Element characteristics of Backhoe assembly ....................................................... 34
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
vii
List of Figures
____________________________________________________________________________
Figure No. Title of the figure Pg.No.
Fig 1. 1 FEA results for optimization ......................................................................................... 11
Fig 1. 2 Showing optimization on connecting rod ..................................................................... 11
Fig 1. 4 Duct lines for ventilation ............................................................................................... 12
Fig 1. 3A- Single crystal structure Fig1.3B-Ceramic coating .................................................... 12
Fig 2. 1 Excavator ...................................................................................................................... 13
Fig 2. 2 Backhoe parts ................................................................................................................ 13
Fig 2. 3 DOF of Backhoe ........................................................................................................... 14
Fig 2. 4 Bucket dimension .......................................................................................................... 15
Fig 2. 5 Parameters used in Backhoe calculation ....................................................................... 16
Fig 2. 6 showing stick dimensions ............................................................................................. 18
Fig 2. 7 showing details of stick cross section ........................................................................... 18
Fig 2. 8 Showing Boom dimensions .......................................................................................... 19
Fig 2. 9Showing details of Boom cross section ......................................................................... 20
Fig 2. 10 Free body diagram of Backhoe ................................................................................... 21
Fig 2. 11 Joints provided in ADAMS ......................................................................................... 22
Fig 2. 12 Reach diagram obtained in ADAMS .......................................................................... 23
Fig 2. 13 Graph showing Distance traveled by bucket ............................................................... 23
Fig 2. 14 Velocity graph at Bucket hinge ................................................................................... 24
Fig 2. 15 Angular acceleration graph at Bucket hinge ............................................................... 25
Fig 2. 16 Angular velocity at Stick hinge ................................................................................... 26
Fig 2. 17 Showing Angular acceleration at stick hinge .............................................................. 27
Fig 2. 18 Angular velocity at Boom hinge ................................................................................. 28
Fig 2. 19 Showing Angular acceleration at Boom hinge ............................................................ 29
Fig 2. 20 Boom & Bucket modeled in CATIA .......................................................................... 29
Fig 2. 21 Bucket link & Bucket quick attach link modeled in CATIA ...................................... 30
Fig 2. 22 Stick and Pivot bucket link modeled in CATIA ......................................................... 30
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
viii
Fig 2. 23 Backhoe assembly created in CATIA ......................................................................... 30
Fig 3. 1 Showing Solid45 element DOF .................................................................................... 31
Fig 3. 2 Showing Mass21 element DOF .................................................................................... 32
Fig 3. 3 Bucket meshed in HYPERMESH ................................................................................. 32
Fig 3. 4 Boom & Stick meshed in HYPERMESH ..................................................................... 33
Fig 3. 5 Showing assembly meshed in HYPERMESH .............................................................. 34
Fig 3. 7 Showing Displacement sum vector results of bucket ................................................... 35
Fig 3. 6 Loads and Boundary conditions on Bucket .................................................................. 35
Fig 3. 8Showing Vonmises stress results of bucket ................................................................... 36
Fig 3. 9 Boundary condition and loads on stick & Boom assembly .......................................... 37
Fig 3. 10 Displacement results of stick & Boom assembly ........................................................ 37
Fig 3. 11 Showing Vonmises stress result of stick & Boom assembly ...................................... 38
Fig 3. 12 Showing boundary condition on Backhoe assembly .................................................. 39
Fig 3. 13 Showing displacement results of Backhoe assembly .................................................. 40
Fig 3. 14 Showing Vonmises stress results of Backhoe assembly ............................................. 40
Fig 3. 16 Boom Modeled - Before modifying shape .................................................................. 41
Fig 3. 15 Idealisation of simply supported beam as Boom ........................................................ 41
Fig 3. 17 Boom Modeled - after modifying shape ..................................................................... 42
Fig 3. 19 Stick modeled before modification of shape ............................................................... 42
Fig 3. 18 Showing stress concentration at the sharp corner ....................................................... 42
Fig 3. 20 Stick modeled after modification of shape .................................................................. 43
Fig 3. 21 Displacement result comparison before and after optimization .................................. 43
Fig 3. 22 Vonmises stress result comparison before and after optimization .............................. 44
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
ix
List of Symbols
____________________________________________________________________________
Symbol Description Units
F Force N
ɽ Torque N-m
K
m
d
l
f
a ө
Bulk modulus
Mass
Diameter
Length
Frequency
Angular velocity
Angle
N/m2
kg
m
m
Hz
m/s
deg
g Acceleration due to gravity - 9.81 m/s2
ω
σ
P
A
E
S
M
I
Angular acceleration
Stress
Pressure
Area
Young’s modulus
Factor of safety
Bending moment
Moment of inertia
m/s2
N/m2
N/m2
m2
N/m2
N-mm
N-mm
Machinery design -1
10
PART-A
CHAPTER 1
1.0 Introduction: The mechanical designer uses the engineering tools (such as mathematics, statistics,
computers, graphics, and languages) etc, to formulate the plan or design for finding the solution for
specific problem. While designing mechanical structures the various aspects are required to
considered by the designer, such as functionality of the structure, safety of structure, reliable,
competitors in market, usable, manufacturable and marketable. In this debate by considering the
four various aspects under different subtitles the debate has to be answered by supporting with case
study by selecting a mechanical component under above mentioned aspects.
1.1 Mechanical strength, design optimization and aesthetic [1],[2] & [3]: The component were the mechanical strength, design optimization and aesthetic are
considered in the mechanical structure is titanium nitrate (TiN) coated drill bit. Usually drill bits
made of HSS (high speed steel) material, it is used to perform drilling operation. Were the HSS
material is selected as cutting tool material by considering the strength, which has red hardness
property were the material will not loose its hardness at the
elevated temperature, the material has the hardness of 67HRC
this property can be considered under strength[1]. For design
optimization and aesthetic purpose the HSS material is coated
with titanium nitrate material by physical vapor deposition
processes. In the test conducted by Kadam M.S [2] the results
are shown in Table1.1. Were the results shows TiN drill with parameters shown in Table1.2
operates at high torque and less chip load for the same diameter, type, feed and rpm used for HSS
drill without TiN coating which in turn TiN coated drill reduces the cycle time thus functional
optimation is carried out in HSS drill bit by TiN coating. The TiN covers the ascetics part by “TiN
is used to harden and protect cutting and sliding surfaces, for decorative purposes (due to its gold
appearance)”[3] according to Wikipedia.
Table 1. 1 Drill bit parameters
Table 1. 2 Results of comparison of TiN & HSS dry drill performance
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
11
1.2 Mechanical strength and design optimization [4] & [5]: The mechanical strength and design optimization alone is consideration the connecting rod,
which connects piston to the crank shaft and
transmits the power from piston to crankshaft.
The connecting rod undergoes high loads, It
undergoes high cyclic loads of the order of 108 to
109 cycles [4], which range from high
compressive loads due to combustion, to high
tensile loads due to inertia therefore the
connecting rod is designed considering the fatigue
strength. The design optimization is done for
connecting rod in order to reduce the weight and
reduce the manufacturing cost Alex Antoc
MAHLE Industries Inc[5], conducted an experiment on design of light weight connecting rod in
which by using FEA analysis is shown in Fig1.2 were red area is non-stressed and black area is
stressed portion. He found possible modification in design and carried out the weight optimization
is done and the results are plotted in graph as shown in Fig1.1. The aesthetic will not be considered
in this structure as it is enclosed within the cylinder housing.
Fig 1. 2 FEA results for optimization
1.3 Mechanical strength [6]: The strength alone is considered for structure of turbine blades, The blades are responsible
for extracting energy from the high temperature, high pressure gas produced by the combustor. As
the jet turbine blades are exposed to very high temperature about 1350ᵒC. According to Harry
Fig 1. 1 Showing optimization on connecting rod
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
12
Bhangu[6] “Specified life of stage 1 turbine blade is +50,000 hours ≈ 6 years, for six years the
blade has to rotate continuously at 3000 RPM in a very harsh environment” in order to obtain the
life in the turbine blades only the strength is considered were the optimization and aesthetic is
totally neglected. In order to avoid the creep failure in blade the blade is made of super alloy with
single crystal structure as shown in Fig1.3A. In order to withstand the temperature ceramic coating
is done as shown in Fig1.3B.
1.4 Aesthetic [7]:
The aesthetic alone is considered in the structures like duct work which is used for ventilation
purpose, were when the pipe lines are exposed outside the aesthetic becomes the important part of
the structure. The case study, Cox, Kliewer & Company,[7] a Virginia-based architectural firm,
while relocating their working place they introduced innovative design of duct which proves the
modern look and cool and pure air throughout the building as shown in the Fig1.4. These duct lines
are usually of polymeric plastic material and the cut section is shown in the below Fig which results
in aesthetic alone were strength and optimization is neglected.
Fig 1. 4 Duct lines for ventilation
1.5 Conclusion:
The mechanical designer should keep in mind the design is the combination of various aspects like
strength, optimization and aesthetic these requirements a changes with the application of the
structure therefore it is essential to study the structure thoroughly before designing.
Fig 1. 3A- Single crystal structure Fig1.3B-Ceramic coating
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
13
PART-B
CHAPTER 2 ________________________________________________________________________________ 2.0 Introduction:
Backhoe loader is the power driven mechanism used for digging, moving or transporting of
the loose gravel, sand or soil. It is general purpose construction equipment which is the combination
of i) A Tractor ii) A loader and iii) A back hoe. The core structure of the backhoe loader is built on
the tractor; the loader is fixed in the front portion were it is used to carry the loose material and the
backhoe is fixed in the back portion of the backhoe loader. The backhoe is the main tool of the
backhoe loader. It's used to dig up hard, compact material, usually earth, or to lift heavy loads.
The Backhoe portion has 3 segments:
• The boom
• The stick and
• The bucket
2.1 Backhoe portion:
In this assignment the backhoe portion has to analysed the backhoe
portion and based on the function the backhoe portion comes under the
first class lever in which the fulcrum is placed between the load and effort
as shown in the Fig2.2. The part of the backhoe holding the bucket is
called the stick and the stick is attached to another part of the backhoe
called the boom. When the hydraulic piston attached to the boom pulls the
stick, the stick pivots on its fulcrum, which is where it is attached to the
boom. This causes the other end of the stick to lift and so the mechanism is
classified under the first class lever.
Fig 2. 1 Excavator
Fig 2. 2 Backhoe parts
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
14
2.1.1 Degrees of freedom of backhoe:
The DOF comparison between the human arm
and the backhoe is shown in the Fig2.3. As the
backhoe functions similar to human arm, but
DOF in the backhoe mechanism is less than
human arm as the human arm has 8 DOF while
the backhoe has 4 DOF.
The various joints and pairs used in the
backhoe mechanism to obtain these DOF
are:
• Revolute joints – has one DOF able to rotate about its axis (lower pair as a journal bearing
with a pin is used to obtain the DOF)
• Prismatic joints – has one DOF able to translate about its axis (lower pair as a hydraulic
cylinder with piston is used to obtain the DOF)
In the backhoe mechanism there are 12 links which are:
i) Ground – the link fixed to the tractor. ii) Boom – the 2nd link.iii) Hydraulic cylinder – as 3
cylinders are used can be considered as 3 more links iv) Pistons – can be considered as 3 more links
v) Stick – 9th link vi) two links connected to bucket and stick vii) Bucket – 12th link.
As 3 hydraulic cylinders are used and therefore 3 prismatic pairs are there and the rest are revolute
pairs. If the 3 hydraulic cylinders are actuated the (output link) bucket is controlled in planar
motion. Were the (output link) bucket can possibly have 2 translation motion and 1 rotational
motion in the plane and the other DOF for the (output link) bucket is rotational a swing motion
provided to the boom which in turn provide the motion to bucket to change its plane.
2.2 The materials used in backhoe:
The materials used in the construction of the backhoe are:
Si.no Part description Material used
01 Boom Medium strength alloy steel casted
to the shape
02 Stick Medium strength alloy steel casted
to the shape
Fig 2. 3 DOF of Backhoe
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
15
03 Hydraulic cylinder Seamless steel tubes are rolled and
formed
04 Hydraulic cylinder piston Stainless steel with chrome plated
05 Seals Elastomeric plastic (to with stand
high temperature)
06 Buckets Ductile cast iron
07 Plain bearing Babbit, bi-metal
08 Hinge pin Hardened carbon steel
Table 2. 1 Showing materials used in Backhoe assembly
2.3 Calculating bucket capacity calculation:
Bucket capacity is a measure of the maximum volume of the material that can be
accommodated inside the bucket of the backhoe excavator. In the Fig() the dimensions of the
bucket of which bucket capacity is to be calculated is shown.
Fig 2. 4 Bucket dimension
The bucket capacity can be calculated by:
VBC = VDC +VEC
Were, VBC = Bucket capacity, VDC = Dump capacity and VEC = Excess capacity
The dump capacity (VDC) can be calculated by:
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
16
Were, = area of inner surface of bucket, Wr = inside width of the bucket and Wf = Outer
width of bucket.
The excesses capacity (VEC) can be calculated by:
� �� ��
Therefore the bucket capacity (VBC) =
2.3.1Calculating digging force calculation:
As the analysis is carried out in planar were only the 3 DOF of the bucket digging force is
calculated by finding the curling force of the bucket (FB) and the mass force of the bucket (FS) as
shown below:
Fig 2. 5 Parameters used in Backhoe calculation
The curling forces are calculated by using the formula:
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
17
π�
Were, FB = curling force of bucket, the other terms dA, dB, dC, and dD, shows the distances as
shown in Fig().
The mass force is calculated using the formula:
π�
Were, FS = Mass force on arm, the other terms DA, dE, and dF, shows the distances as shown in
Fig().
By using these formulas the bucket curl or breakout force is calculated as 8000N and the arm mass
force or digging force is calculated as 4500N. the maximum lifting capacity of bucket is calculated
as 2000N.
2.3.2 Stick and arm length calculation:
The yield strength of carbon steel (ASTM - A 514) = 690 N/mm2.
Factor of safety = 5[8]
According to Roymech, UK standards [8]“The FOS =5,Should also be used with better-known
materials that are to be used in uncertain environments or subject to uncertain stresses”. As the
backhoe experiences uncertain stresses by the angle of digging suppose if the bucket angle is
around 45o the digging force experienced by the bucket will be less similarly if the bucket angle
moves away from 45o the force required will be more it depends on the skill of the operator.
Therefore allowable yield strength = 690/5 = 138 N/mm2.
2.3.3 Assumptions made in calculation:
• The boom cross section is idealized to channel section.
• The stick cross section is idealized to box cross section.
• The maximum bending stress does not exceed the allowable yield strength 138 N/mm2
value.
• Thus in bending equation instead of the bending stress the allowable yield strength value is
substituted.
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
18
2.3.4 Idealized cross section of stick:
The shape of the stick is shown in Fig2.6. Were the dimensions of boom, the length and the cross
section are shown for idealization of cross section and to find the length.
Fig 2. 6 showing stick dimensions
The cross section of the boom is idealized to the rectangular tubular section which has the
breadth of 102 mm and depth of 127 mm and the wall thickness is idealized as 6.5 mm. the details
of the values of the cross section such as area, moment of inertia etc, are shown in the Fig2.7 below.
Fig 2. 7 showing details of stick cross section
2.3.5 Finding the length using bending equation:
σ
Were, M = bending moment in N-mm, I = moment of inertia inmm4, σ = bending stress in N/mm2
and y = distance from neutral axis to the outer surface in mm.
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
19
In the bending equation instead of the bending stress the allowable yield strength value is
substituted as per the assumption made as the maximum bending stress will be allowed to reach the
value of 138 N/mm2.
M = 13908661.42 N-mm.
Moment = force X distance
Were, the force is taken as the bucket curl or breaking force as calculated which is 8000N.
Therefore the link length is:
Stick length = Moment / Breaking force
= 13908661.42 / 8000
= 1738.58mm
2.3.6 Idealized cross section of Boom:
The shape of the boom is shown in Fig2.8. Were the dimensions of boom, the length and the cross
section are shown for idealization of cross section and to find the length.
Fig 2. 8 Showing Boom dimensions
The cross section of the boom is idealized to the channel section which has the breadth of
113 mm and depth of 152 mm and the wall thickness is idealized as 6.5 mm. the details of the
values of the cross section such as area, moment of inertia etc, are shown in the Fig2.9 below.
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
20
Fig 2. 9Showing details of Boom cross section
2.3.7 Finding the length using bending equation:
σ
Were, M = bending moment in N-mm, I = moment of inertia inmm4, σ = bending stress in N/mm2
and y = distance from neutral axis to the outer surface in mm.
In the bending equation instead of the bending stress the allowable yield strength value is
substituted as per the assumption made as the maximum bending stress will be allowed to reach the
value of 138 N/mm2.
M = 16759736.84 N-mm.
Moment = force X distance
Were, the force is taken as the bucket curl or breaking force as calculated which is 8000N.
Therefore the link length is:
Stick length = Moment / Breaking force
= 16759736.84 / 8000
= 2094.96mm.
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
21
2.3.8 Finding the pin diameter using bending equation:
σ
Were, M = bending moment in N-mm, I = moment of inertia inmm4, σ = bending stress in N/mm2
and y = distance from neutral axis to the outer surface in mm.
The yield strength of carbon steel (ASTM - A 514) = 690 N/mm2.
Factor of safety = 2.5[8]
According to Roymech, UK standards [8]“The FOS =2.5 Materials obtained for reputable
suppliers to relevant standards operated in normal environments and subjected to loads and
stresses that can be determined using checked calculations”
Therefore allowable yield strength = 690/2.5 = 276 N/mm2.
In the bending equation instead of the bending stress the allowable yield strength value is
substituted as per the assumption made as the maximum bending stress will be allowed to reach the
value of 230 N/mm2.
.
2.4 Free body diagram of Backhoe:
Fig 2. 10 Free body diagram of Backhoe
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
22
The backhoe while lifting the mass 1m above ground level the stick portion is subjected to the
various forces shown below:
• Resultant force from pin “D”
• Resultant force from pin “F”
• Force, FBE
• Force, FHI
• Force, FBC
The backhoe while lifting the mass 1m above ground level the Bucket portion is subjected to the
various forces shown below:
• Mass “W”
• Resultant force from pin “D”
• Force, FBA
The backhoe while lifting the mass 1m above ground level the Boom portion is subjected to the
various forces shown below:
• Resultant force from pin “H”
• Resultant force from pin “F”
• Force, FHI
2.4.1 Kinematic analysis in ADAMS: The dimensions of the backhoe is collected from the JCB and using the modeling software
CATIA R16 the parts are modeled as per the dimensions obtained which is scale down to the ratio
of 1:2 and the assembly is converted into parasoild to import in ADAMS software for kinematic
analysis. The various joints provided in the ADAMS is shown in the Fig2.11.
Fig 2. 11 Joints provided in ADAMS
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
23
2.4.2 The reach diagram obtained in ADAMS:
Fig 2. 12 Reach diagram obtained in ADAMS
2.5 Range graph of backhoe:
Fig 2. 13 Graph showing Distance traveled by bucket
For the backhoe mechanism the trace spline is plotted along the path taken by the bucket in
ADAMS which in turn provide the detail of the range covered by the backhoe as shown in the
Fig2.12.
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
24
Result interpretation:
The range graph shown in the Fig2.13 has time in second in horizontal axis and length in
mm in vertical axis as by using the step function in ADAMS, the motion is given to hydraulic
cylinders connected to stick, boom and bucket of backhoe and the graph is plotted from which the
result interrupted for the scale down model as the modeling is done to the scale of 1:2 from the
graph can be observed that the maximum distance covered by backhoe is 961.00mm for the scale
down model.
2.6 Velocity and acceleration results of backhoe:
The angular velocity and angular acceleration results are mapped on the graph using ADAMS
software at the various pin joints connecting the links. The results at the following joints are shown:
i) Ground and boom.
ii) Boom and stick.
iii) Stick and bucket.
2.6.1 Result of angular velocity graph at bucket hinge:
Fig 2. 14 Velocity graph at Bucket hinge
Result interpretation:
The angular velocity graph at bucket hinge is shown in the Fig2.14 has time in second in
horizontal axis and angular velocity in degree/second in vertical axis as by using the step function
in ADAMS the motion is given to hydraulic cylinder connected to bucket the graph is plotted. From
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
25
the graph for the scale down model (1:2) the result obtained is the maximum velocity is 7.094deg/s.
In which the for the first 6second the velocity increases from zero to maximum and then in next 4
second the velocity decreases from maximum to zero.
2.6.2 Result of angular acceleration graph at bucket hinge:
Fig 2. 15 Angular acceleration graph at Bucket hinge
Result interpretation:
The angular acceleration graph at bucket hinge is shown in the Fig2.15 has time in second in
horizontal axis and angular acceleration in degree/second2 in vertical axis as by using the step
function in ADAMS the motion is given to hydraulic cylinder connected to bucket the graph is
plotted. From the graph for the scale down model (1:2) the result obtained is the maximum angular
acceleration is 3.746deg/s2. In which the angular velocity is 2.61 deg/s2 is observed at the beginning
the transition from zero to 2.616deg/s2 takes in short time and as at the 6th second the velocity gets
maximum as shown in the velocity graph fig2.14 the effect can be observed in acceleration graph in
Fig2.15 were at the 6th second the acceleration reaches to zero. At the 10th second the velocity
reaches to zero as shown in the velocity graph fig2.14 the effect can be observed in acceleration
graph in Fig2.15 were at the 10th second the acceleration reaches to maximum value of 3.746deg/s2
then reaches to zero as the cylinder stroke ends.
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
26
2.6.3 Result of angular velocity graph at stick hinge:
Fig 2. 16 Angular velocity at Stick hinge
Result interpretation:
The angular velocity graph at stick hinge is shown in the Fig2.16 has time in second in
horizontal axis and angular velocity in degree/second in vertical axis as by using the step function
in ADAMS the motion is given to hydraulic cylinder connected to stick the graph is plotted. As the
hydraulic cylinder is actuated in the time interval of 10s to 20s the graph is plotted between these
timings. From the graph for the scale down model (1:2) the result obtained is the maximum velocity
is 8.174deg/s. In which the for the first 6second the velocity increases from zero to maximum and
then in next 4 second the velocity decreases from maximum to zero.
2.6.4 Result of angular acceleration graph at stick hinge:
Result interpretation:
The angular acceleration graph at stick hinge is shown in the Fig2.17 has time in second in
horizontal axis and angular acceleration in degree/second2 in vertical axis as by using the step
function in ADAMS the motion is given to hydraulic cylinder connected to stick the graph is
plotted. As the hydraulic cylinder is actuated in the time interval of 10s to 20s the graph is plotted
between these timings. From the graph for the scale down model (1:2) the result obtained is the
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
27
maximum angular acceleration is 5.246deg/s2. In which the angular velocity is 3.19 deg/s2 is
observed at the beginning the transition from zero to 3.19deg/s2 takes in short time and as at the 16th
second the velocity gets maximum as shown in the velocity graph fig2.16 the effect can be
observed in acceleration graph in Fig2.17 were at the 16th second the acceleration reaches to zero.
At the 20th second the velocity reaches to zero as shown in the velocity graph fig2.16 the effect can
be observed in acceleration graph in Fig2.17 were at the 20th second the acceleration reaches to
maximum value of 5.246deg/s2 then reaches to zero.
Fig 2. 17 Showing Angular acceleration at stick hinge
2.6.5 Result of angular velocity graph at Boom hinge:
Result interpretation:
The angular velocity graph at boom hinge is shown in the Fig2.18 has time in second in
horizontal axis and angular velocity in degree/second in vertical axis as by using the step function
in ADAMS the motion is given to hydraulic cylinder connected to stick the graph is plotted. As the
hydraulic cylinder is actuated in the time interval of 20s to3 the graph is plotted between these
timings. From the graph for the scale down model (1:2) the result obtained is the maximum velocity
is 6.946deg/s. In which the for the first 6second the velocity increases from zero to maximum and
then in next 4 second the velocity decreases from maximum to zero.
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
28
Fig 2. 18 Angular velocity at Boom hinge
2.6.6 Result of angular acceleration graph at Boom hinge:
Result interpretation:
The angular acceleration graph at boom hinge is shown in the Fig2.19 has time in second in
horizontal axis and angular acceleration in degree/second2 in vertical axis as by using the step
function in ADAMS the motion is given to hydraulic cylinder connected to boom the graph is
plotted. As the hydraulic cylinder is actuated in the time interval of 20s to 30s the graph is plotted
between these timings. From the graph for the scale down model (1:2) the result obtained is the
maximum angular acceleration is 3.962deg/s2. In which the angular velocity is 2.143 deg/s2 is
observed at the beginning the transition from zero to 2.143deg/s2 takes in short time and as at the
26th second the velocity gets maximum as shown in the velocity graph fig2.18 the effect can be
observed in acceleration graph in Fig2.19 were at the 26th second the acceleration reaches to zero.
At the 30th second the velocity reaches to zero as shown in the velocity graph fig2.18 the effect can
be observed in acceleration graph in Fig2.19 were at the 30th second the acceleration reaches to
maximum value of 3.9628deg/s2 then reaches to zero.
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
29
Fig 2. 19 Showing Angular acceleration at Boom hinge
2.7 Modeling of Backhoe in CATIA:
The 3D geometric model of the parts of the backhoe are created by constructive boundary
method, where initially sketcher work bench is used and part work bench is used to create the part
model and assembly work bench is used to assemble all the parts and to analyze the clash and
finally the various parts of backhoe is shown in the Fig below.
Fig 2. 20 Boom & Bucket modeled in CATIA
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
30
Fig 2. 21 Bucket link & Bucket quick attach link modeled in CATIA
Fig 2. 22 Stick and Pivot bucket link modeled in CATIA
Fig 2. 23 Backhoe assembly created in CATIA
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
31
PART-C
CHAPTER 3
________________________________________________________________________________
3.0 Introduction:
In this chapter the modeled backhoe part is converted into neutral IGES format and imported into
HYPER MESH 2009 software and meshing is carried out at 3forms which are:
i) Bucket alone.
ii) Boom and stick together.
iii) Whole assembly together – Bucket, Stick and Boom.
In the mesh elements the various properties of the elements are defined such as element type is
defined in ET-reference the material is defined as steel and the properties of young’s modulus,
density and Poisson’s ratio is defined before exporting to the ANSYS.
3.1 Finite element model conversion:
The various elements used in meshing are;
Solid 45:
It is used in 3 solid dimensional structures, were tetrahedral element has 5 nodes each node
has 3DOF which are translation along X, Y and Z axis. The output of the element is nodal
displacements included in the overall nodal solution. As for the assignment stress distribution has to
be found solid45 is capable of producing the results the element is selected for all the structures of
solid parts such as boom, stick and bucket.
Fig 3. 1 Showing Solid45 element DOF
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
32
Mass21:
The mass element has 6 DOF, 3 translations and 3 rotations along X, Y and Z axis. The
mass element is defined by a single node, concentrated mass components. As in the pin joints it is
required to distribute and transfer the forces to one component to other such as boom to stick joint
the load is applied to the mass node and distributed through rigid elements.
Fig 3. 2 Showing Mass21 element DOF
CERIG:
These elements used to generate rigid region. The first node picked will be the master node,
and subsequent nodes picked will be slave nodes. These 1D elements are used to transfer the forces
applied to the mass node to the components these elements are used with mass nodes at the pin
joints.
3.1.1 Bucket:
The scale down model (1:2) of the bucket modeled using in CATIA R16 is converted into the finite
element model by meshing and applying the boundary condition in Hyper mesh 2009 software. The
meshed model is shown in the Fig3.3. Table 3. 1 Element characteristics of Bucket
Element Types
used
i) Solid 45
ii) Mass21
iii) Cerg
Element shape Quad, Tetrahedral element
Jacobian Minimum jacobian is 1.00 - 0% failed
Volume skew The minimum tetra collapse is 0.91 – 1
% failed
Aspect ratio The maximum aspect ratio is 4.32 –
0% failed. Fig 3. 3 Bucket meshed in HYPERMESH
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
33
The details of the mesh are shown in Table-1 the results are attached in [Appendex-1]. The 1D
mass and rigid element are used at the pin joints. Before exporting to the ANSYS the elements are
defined in ET-reference the material is defined as steel and the properties of young’s modulus,
density and Poisson’s ratio is defined in hyper mesh itself.
3.1.2 Boom and stick:
For the FEA analysis as the boom and stick is to be analysed together the scale down model
(1:2) of the stick and the boom part modeled using in CATIA R16 is converted into the finite
element model by meshing and applying the boundary condition in hyper mesh 2009 software. The
meshed model is shown in the Fig3.4.
The details of the mesh are shown in Table-1 the results are attached in [Appendex-1]. The 1D
mass and rigid element are used at the pin joints. Before exporting to the ANSYS the elements are
defined in ET-reference the material is defined as steel and the properties of young’s modulus,
density and Poisson’s ratio is defined in hyper mesh itself.
3.1.3 Backhoe assembly:
For the FEA analysis as the whole backhoe assembly has to be analysed together the scale
down model (1:2) of the stick, boom and bucket part modeled using in CATIA R16 is converted
Element
Types used
i) Solid 45
ii) Mass21
iii) Cerg
Element
shape
Quad, Tetrahedral element
and link
Jacobian Minimum jacobian is 1.00 -
0% failed
Volume skew The minimum tetra collapse
is 1.00 – 17 % failed
Aspect ratio The maximum aspect ratio is
136.09 – 1% failed.
Table 3. 2 Element characteristics of Boom and Stick Fig 3. 4 Boom & Stick meshed in HYPERMESH
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
34
into the finite element model by meshing and applying the boundary condition in hyper mesh 2009
software. The meshed model is shown in the Fig3.5.
Fig 3. 5 Showing assembly meshed in HYPERMESH
The details of the mesh are shown in
Table-1 the results are attached in [Appendex-1].
The 1D mass and rigid element are used at the pin
joints. Before exporting to the ANSYS the
elements are defined in ET-reference the material
is defined as steel and the properties of young’s
modulus, density and Poisson’s ratio is defined in
hyper mesh itself.
Element
Types used
i) Solid 45
ii) Mass21
iii) Cerg
Element
shape
Link, Quad, Tetrahedral
element
Jacobian Minimum jacobian is 1.00 -
0% failed
Volume skew The minimum tetra collapse
is 1.00 – 2 % failed
Aspect ratio The maximum aspect ratio is
148.32 – 1% failed.
Table 3. 3Element characteristics of Backhoe assembly
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
35
3.2 Boundary conditions used for analysis:
3.2.1 Boundary conditions and load analysis of bucket:
As the bucket is scale
down, model the breaking force
obtained by the calculation is
8000N. The applied force on to
the bucket is 4000N , in order to
apply load on to the bucket by
considering the breaking force
acting on the bucket wedge, were
the bucket used to dig the soil the
force of 400N is applied in
ADAMS the values are measured
at the joints and those values are
taken as the input to the ANSYS software the values of the forces obtained at the joint are X-axis =
1009N, Y-axis = 6004N and Z-axis = -2124N. These values are applied in the ANSYS on the mass
node created as shown in the Fig3.6.
3.2.2 The Displacement of the bucket:
Fig 3. 7 Showing Displacement sum vector results of bucket
Fig 3. 6 Loads and Boundary conditions on Bucket
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
36
Result interpretation:
By applying the loads obtained in the ADAMS and by appropriate constraining the result of the
displacement sum vector obtained is 0.329876mm were the displacement is maximum at the face
were the digging wedges are place in the bucket. The displacement is minimum at the area were all
DOF constrain is applied as shown in the Fig3.8.
3.2.3 Vonmises stress in the bucket:
Fig 3. 8Showing Vonmises stress results of bucket
As per the theory of failure vonmises theory gives the best results for the multi axial loading
component therefore in order to determine the failure of the bucket the vonmises stress is found
which should be less while compared to the yield strength of the material after considering the FOS.
In the bucket the maximum Vonmises stress is obtained at the pin joint were all DOF is constrained
were the stress value is 149.236N/mm2.
3.2.4 Boundary conditions and load analysis of Stick and boom:
As the boom and stick is scale down model, the breaking force obtained by the calculation is
8000N. The applied force on to the bucket wedge is 4000N, in ADAMS the values are measured at
the joints and those values are taken as the input to the ANSYS software the values of the forces
obtained at the joint are:
i) X-axis = 1009N, Y-axis = 6004N and Z-axis = -2124N.
ii)X-axis = 1758N, Y-axis = -403N and Z-axis = 0N.
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
37
iii)X-axis = -1182N, Y-axis = 164N and Z-axis = -127N.
These values are applied in the ANSYS on the mass node created as shown in the Fig().
Fig 3. 9 Boundary condition and loads on stick & Boom assembly
3.2.5 The Displacement of the boom and stick:
Fig 3. 10 Displacement results of stick & Boom assembly
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
38
Result interpretation:
By applying the loads obtained in the ADAMS and by appropriate constraining the result of
the displacement sum vector obtained are 4.969 mm were the displacement is maximum at the
region of the pin joint connecting the bucket were the force due to the bucket will be maximum.
The displacement is minimum at the region of the boom and at the larger cross section of the stick
as shown in the Fig3.10.
3.2.6 Vonmises stress in the stick and boom:
Fig 3. 11 Showing Vonmises stress result of stick & Boom assembly
Result interpretation:
As per the theory of failure vonmises theory gives the best results for the multi axial loading
component therefore in order to determine the failure of the boom and stick assembly the vonmises
stress is found which should be less while compared to the yield strength of the material after
considering the FOS. In the bucket the maximum Vonmises stress is obtained at the pin joint were
all DOF is constrained and the forces are applied and in the stick part the stress pattern is found at
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
39
the area were the change in the cross section takesplace. The maximum vonmises stress value
obtained for the scale down model is 195.504N/mm2.
3.2.7 Boundary conditions and load analysis of backhoe assembly:
The backhoe assembly consist of boom, stick and bucket, for the scale down model, the
breaking force obtained by the calculation is 8000N. The applied force on to the bucket wedge is
4000N. In ADAMS the values are measured at the joints and those values are taken as the input to
the ANSYS software the values of the forces obtained at the joint are:
i) X-axis = 1009N, Y-axis = 6004N and Z-axis = -2124N. - Stick and bucket joint
ii) X-axis = 1758N, Y-axis = -403N and Z-axis = 0N. – Stick and boom joint
iii) X-axis = -1182N, Y-axis = 164N and Z-axis = -127N. – Boom end joint
iv) X-axis = 0N, Y-axis = 4621N and Z-axis = -123N. - Bucket joint
These values are applied in the ANSYS on the mass node created as shown in the Fig3.12.
Fig 3. 12 Showing boundary condition on Backhoe assembly
3.2.8 The Displacement of the backhoe assembly:
Result interpretation:
By applying the loads obtained in the ADAMS and by appropriate constraining the result of
the displacement sum vector obtained are 0.22129 mm were the displacement is maximum at the
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
40
region of the pin joint end of boom connecting to the tractor and at the wedge portion of bucket
were the force due to the digging occurs shows maximum displacement. For the backhoe structure
as the forces at the different joints tries to make the structure into the equilibrium condition the
displacement is found less in the most of the region of the backhoe assembly Fig3.13.
Fig 3. 13 Showing displacement results of Backhoe assembly
3.2.9 Vonmises stress in the stick and boom:
Fig 3. 14 Showing Vonmises stress results of Backhoe assembly
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
41
Result interpretation:
As per the theory of failure vonmises theory gives the best results for the multi axial loading
component therefore in order to determine the failure of the backhoe assembly consit of bucket,
boom and stick assembly the vonmises stress is found which should be less while compared to the
yield strength of the material after considering the FOS. In the bucket the maximum Vonmises
stress is obtained at the pin joint were the force of the bucket is applied. For the backhoe structure
as the forces at the different joints tries to make the structure into the equilibrium condition the
stressed regions are found less and the maximum vonmises stress value obtained for the scale down
model is 119.389N/mm2.
3.3 Improving the asthetic without compromising the strength:
3.3.1 Modification in Boom:
The beam carting the uniformly distributed load is
shown in the Fig3.15 which is similar to the boom
structure, were the maximum bending moment
occurs at the middle of the beam similar to this in
boom also the bending moment will be maximum
at the middle therefore while modifying the
structure for the aesthetic purpose thaking this into
consideration the structure is modified the initial
shape is shown in the Fig3.16. The modified shape
is shown in Fig3.17.
Fig 3. 16 Boom Modeled - Before modifying shape
Fig 3. 15 Idealization of simply supported beam as Boom
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
42
Fig 3. 17 Boom Modeled - after modifying shape
3.3.2 Modification in stick:
In order to improve the aesthetic without out
compromising the strength the shape is been modified in stick
were initial model there is sharp edges at the change in cross
section which will results in stress concentration as shown in
the Fig3.18 were the sudden change in the cross section with
sharp edges is modified by providing the radius to the section at
the region. The Fig3.19 shows the initial model and Fig3.20
shows after modifying the section.
Fig 3. 19 Stick modeled before modification of shape
Fig 3. 18 Showing stress concentration at the sharp corner
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
43
Fig 3. 20 Stick modeled after modification of shape
3.4 Result validation after optimisation of structure:
3.4.1 Displacement result comparison:
In the Fig 3.21. The comparison of the results is shown before and after modifying the shapes of
boom and stick for optimization purpose. From the Fig it can be observed that the displacement
region remains same for the both the cases but the displacement slightly increases 1.12mm in the
optimized structure but still it is preferred as the Vonmises stress distribution shows the better
results.
Fig 3. 21 Displacement result comparison before and after optimization
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
44
3.4.2 Vonmises Stress result comparison:
While comparing the Vonmises stress distribution the stress value is decreased for the optomised
structure, were the initial stress value is 195.504 N/mm2 and the value obtained after optimization is
172.581N/mm2. This is lesser than the initial value, the Fig3.22 shows the comparison of Vonmises
stress before and after optimization.
Fig 3. 22 Vonmises stress result comparison before and after optimization
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
45
Learning outcomes:
The module provides the understanding and applications of the basics and the working
principles of different types of machinery. The knowledge gained in the area of design of different
types of mechanical machinery to meet the various functional and operational requirements. The
application of computer aided engineering tools such as CATIA, HYPERMESH, ANSYS and
ADAMS for design, modeling, simulation, analysis, synthesis and optimization of machine
components and system. The module covers the application of the knowledge gained from all the
modules learned before. This includes machine design criteria and general design procedure and the
various mechanical Properties, the mechanical behavior of materials under various loading and the
concepts of strength and failure resistance. The module covers the calculations related to the simple
and complex machines related to wheel, axle and pulleys. The various to be made while designing
the components such as categorizing into compound and plane stress system and considering stress
due to torsion, stress due to bending and performing the stress analysis. The session on fatigue
covers the basic concepts and the importance of the fatigue, Influence of material property,
composition, microstructure and processes on fatigue behavior of metals. The various terminologies
used in fatigue, various types of the fatigue cycles and calculation of fatigue life of the component.
The concepts of crack propagation stress concentration and various methods to improve fatigue life.
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
46
References
________________________________________________________________________________
[1] Unknown, “High Speed Steel” http://www.sharusteels.com/high-speed-steel.html Retrieved on
03/08/2012.
[2] Kadam M.S, Pathak S.., “Experimental Analysis and Comparative Performance of Coated and
Uncoated Twist Drill Bit Dry Machining” http://www.ijrmet.com/vol1/kadam.pdf retrieved on
11/08/2012.
[3] Unknown, “Titanium nitride” http://en.wikipedia.org/wiki/Titanium_nitride retrieved on
07/08/2012.
[4] Pravardhan S. Shenoy, “Dynamic Load Analysis and Optimization of Connecting Rod”
https://www.forging.org/system/files/field_document/DynamicLoadAnalysis.pdf retrieved on
09/08/2012.
[5] Harry Bhangu, “Effect of design and material defects on gas turbine blade failures”
http://www.braemarsteege.com/lecturenotes/lecture65.pdf retrieved on 11/08/2012.
[6] David Parsons, “Ceramic coatings for jet engine turbine blades”
http://www.carbonbrainprint.org.uk/pdf/CBrainprint-CS01-JetTurbines.pdf retrieved on
06/08/2012.
[7] Riversedge, “Exposed Ductwork Showcases Design and Functionality”
http://www.lindabusa.com/dokumenter/CaseStudyRiversedge.pdf retrieved on 07/08/2012.
[8]Unknown, “Basic Notes on Factor of Safety”
http://www.roymech.co.uk/Useful_Tables/ARM/Safety_Factors.html retrieved on 11/08/2012.
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
47
Appendex-1
Elements check in Hyper mesh:
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
48
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
49
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
50
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
51
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
52
Appendex-2
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
53
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
54
MSRSAS - Postgraduate Engineering and Management Programme - PEMP
Machinery design -1
55