LCD TV MOUNTING BRACKET STUDY

January 18, 2017

BY: Matthew Rossow

The purpose of this study was to evaluate the structural integrity of the engineered design and to

highlight any adverse effects of potential stress on the unit.

Preliminary studies indicated the mounting bracket can withstand the expected 70lbs threshold and

is over-engineered. FEA-Finite Element Analysis software was used to identify potential undesirable

feature characteristics through computer simulation. This document presents chronologically the

process of identification for part failure.

Material: Acrylic (Yield Threshold 45MPa)

ANALYSIS – A

TV MOUNTING BRACKETV on Mises stress Analysis

SUMMARY: No failure observed

ANALYSIS

70 Lbs. FORCE

RISK OF FAILURE

Purpose: The Factor of Safety test set to 2.0 resulted in no failure.

With this design during analysis we do not see any red (failure) elements. It appears to be a valid

design (see Fig.1)

ANALYSIS – B

TV MOUNTING BRACKET Factor of Safety Analysis

SUMMARY: No failure observed

ANALYSIS

70 Lbs. FORCE

RISK OF FAILURE

PHYSICAL DYNAMICS: CD SPRING CLIP STUDY

Physical dynamics was used to determine how the parts interact. Using this information, a spring

clip composed of Delrin 2700 plastic is subjected to 2lbs of force. The clip has yield strength of

63MPa. The blue band along the top of the clip indicates the part will not break.

ENLARGED VIEW

INJECTOR CAP STUDY

January 25th, 2017

BY: MATTHEW ROSSOW

The purpose of this study was to evaluate the structural integrity of a redesign. The original

design for the injector breakaway nozzle was clogging the needle due to an excessive .020 inch

clearance between the injector breakaway head and the nozzle. Molds for the part had already

been produced at the cost of $30,000.

FEA-Finite Element Analysis software was used to identify undesirable feature characteristics

through computer simulation. This document presents chronologically the process of

identification, correction and optimization of engineered features.

Break Away Head Original Design

Material:Acrylic (Medical Grade Cast) (MPa Threshold 45 ≤)

ANALYSIS

BREAK-AWAY HEAD

RISK OF FAILURE .020 inch clearance

Break Away Head Redesign Solution

Material: Acrylic (Medical Grade Cast) (MPa Threshold 45 ≤)

My redesign added .010 inch inserts on top of the breakaway nozzle leaving clearance for fluid

to escape through the needle while preventing the breakaway from clogging the needle. Since

we are adding material, existing molds could be easily modified by drilling the inserts into the

mold.

ANALYSIS – A

INJECTOR NOZZLE BREAK-AWAY (FACTOR OF SAFETY (F.O.S.1))

JANUARY 25, 2017

The design displayed no failure in this analysis with the 10lbs total force. (see Fig.1)

5 LBs FORCE

RUPTURE

ANALYIS A

ANALYSIS – B INJECTOR NOZZLE BREAK-AWAY (VON MISES STRESS ANALYSIS)

JANUARY 25, 2017

The results show the earliest controlled failure in red. The stress analysis indicates a successful

break away occurs with no indication of failure by the inserts. (see Fig.2)

BREAK AWAY

PAP DEVICE F.E.A. ANALYSIS

January 30th, 2017

BY: MATTHEW ROSSOW

The purpose of this study was to evaluate the structural integrity of a pap device used to test for

cervical cancer. The needle was intended to inflate the balloon to collect a sample. The balloon

is then contained and sent to a lab.

The original design for the device could pop the balloon when more than 4lbs was applied and

posed risk of injuring patient since the needle was able to withstand too much force. A needle

that snapped near the tip posed additional risks.

A new design for the needle was needed so that the part would achieve controlled failure under

4lbs force, but stay intact under 3lbs or less.

FEA-Finite Element Analysis software was used to identify undesirable feature characteristics

through computer simulation. This document presents chronologically the process of

identification, correction and optimization of engineered features.

Original Design

NEEDLE

Redesign Solution

My design adds two parallel triangle cut extrudes spaced .95mm apart. The purpose for this design was

to avoid the symmetry of revolved cuts which would make the part stronger, make optimizing/iterating

the design efficient and keep the process of correcting the molds simple.

ANALYSIS – A

PAP DEVICE NEEDLE 4 LBS FORCE (FACTOR OF SAFETY (F.O.S. 2))

JANUARY 30, 2017

The design was able to achieve failure as indicated in red under 4lbs total force. Furthermore

there was no sign of failure at the tip of the needle. (see Fig.1)

RUPTURE

ANALYSIS – B

PAP DEVICE NEEDLE 3 LBS FORCE (FACTOR OF SAFETY (F.O.S. 2))

JANUARY 30, 2017

The design displayed no signs of failure under 3lbs force. Furthermore there was no sign of

failure at the tip of the needle. (see Fig.2)

ANALYSIS – C

PAP DEVICE NEEDLE (VON MISES STRESS ANALYSIS)

JANUARY 30, 2017

The yield strength is used to show the stress limit. The plastic Delrin 2700 needle shows

indications of failure at 4lbs force and is able to withstand 3lbs force.

ENLARGED VIEW

DROP TEST: CELLPHONE CASE STUDY

This case study was about learning to use the drop test simulation. The sample phone case was a dated

model that was not hollowed. Because it was a bulky solid, the case displayed no plastic deformation

from a 5 ft drop test and displayed only 12 thousandths of an inch displacement.

The purpose of this exercise was to introduce us to de-featuring which is important for suppressing

extraneous features to improve cpu calculation times as well as creating planes quickly/efficiently for

multiple points of impact.

PHONE BEZEL & HANDSET DROP TEST STUDY

February 6, 2017

BY: Matthew Rossow

The purpose of this study was to evaluate the structural integrity of a phone bezel and handset with a

drop test to see if the design is sufficient to keep the product from breaking when dropped from a

height of 5 feet. The phone is composed of Nylon 101 plastic (60 MPa) which is a cheaper, lower grade

of Nylon compared to Nylon 6/10 (139 MPa).

There are two assemblies (Handset and Phone Bezel) with a total of 4 areas that required advanced

analysis. FEA-Finite Element Analysis software was used to identify undesirable feature characteristics

through computer simulation.

Material: Nylon 101 (MPa Threshold 60 ≤)

*NOTE: The bottom right corner is identical to the top right corner and will post similar results. The four

handset corners are also symmetric. Duplicate tests were not required.

ANALYIS D*

SYMMETRIC

HANDSET CORNER

ANALYSIS A

BOTTOM LEFT BEZEL CORNER

ANALYIS B

TOP LEFT

BEZEL CORNER

ANALYIS C

TOP RIGHT

BEZEL CORNER

ANALYSIS – A

BOTTOM LEFT BEZEL CORNER [NYLON 101] 5 ft. Drop Test

February 6th, 2017

Results: The Phone Bezel lower left corner displays no signs of failure from the drop test. It is subjected

to 24.5 MPa (shown in red) near the apex of the corner which does not exceed the 60 MPa yield

threshold. Elastic behavior is observed and no engineering changes are required.

SUMMARY: PASS. NO SIGN OF PLASTIC DEFORMATION.

FLOOR

IMPACT

ENLARGED

ANALYSIS – B

TOP LEFT BEZEL CORNER [NYLON 101] 5ft. Drop Test

February 6th, 2017

Results: The top left bezel corner displays possible signs of failure. It is the weakest of the bezel corners

and was subject to 62 MPa (shown in red) at the edges which is just above the yield threshold of 60

MPa. Engineering design changes are advised.

SUMMARY: FAIL. POSSIBLE FRACTURE OR PLASTIC DEFORMATION

ANALYSIS – C

TOP RIGHT BEZEL CORNER [NYLON 101] 5ft. Drop Test

February 6th, 2017

Results: The top right and bottom right phone bezel corners display no signs of failure, but are close to

the yield of 60 MPa. The corner endures a force of 54.6 MPa.

It should be noted that the corner of the depression for the handset was subjected to up to 36 MPa. This

area should also be monitored if the phone were to be tested at greater heights.

SUMMARY: PASS. NO SIGN OF PLASTIC DEFORMATION.

ENLARGED

ANALYSIS – D

HANDSET [NYLON 101] 5ft. Drop Test

February 6th, 2017

Results: The handset corner is subjected to 79 MPa on edges which exceeds the 60 MPa yield threshold

and would be subject to plastic deformation or fracture with the current design. Engineering design

changes are advised.

SUMMARY: FAIL. POSSIBLE FRACTURE OR PLASTIC DEFORMATION.

PHONE BEZEL MOUNTING CLIPS STUDY

February 13, 2017

BY: Matthew Rossow

The purpose of this study was to determine the structural integrity of the engineered design. The phone

design must endure 100 lbs of force from the top of the phone bezel. It is intended to be placed in or

near a bar where it is likely for someone to lean on it. FEA- Finite Element Analysis software was used to

determine the validity of the design.

Material: Acrylic (45MPa Threshold)

Original Design: The original design featured a .100 inch thickness which was set by the shell feature.

CLIP FIXTURE

ANALYSIS

100 Lbs. FORCE

ANALYSIS A

REAR PHONE BEZEL MOUNTING CLIP (FACTOR OF SAFETY (F.O.S. 3))

FEBRUARY 13, 2017

A factor of safety of 3.0 was chosen due to the customer requesting the phone to be designed with

safety requirements and a more sturdy design.

Results: FAIL. The design is insufficient to withstand 100lbs of force. The red areas indicate where the

phone is likely to fracture and plastically deform.

ANALYSIS B

REAR PHONE BEZEL MOUNTING CLIP (VON MISES STRESS ANALYSIS)

FEBRUARY 13, 2017

Results: FAIL. The phone is subjected to 64 MPa at the areas shown in red. This exceeds the 45 MPa

yield strength of the Acrylic and the design will fail under the force of 100lbs.

Redesign: An additional .400 inches were added to the back of the rear bezel. The purpose for this

redesign was to increase the wall thickness to a total .500 inches so the clips could withstand more force

while also not disturbing the layout of the internal components. Fixing the mold for the part will also be

a straightforward process of removing these inches from existing molds.

ANALYSIS C

REAR PHONE BEZEL MOUNTING CLIP REDESIGN (FACTOR OF SAFETY (F.O.S. 3))

FEBRUARY 13, 2017

Results: PASS. The mounting clips were able to withstand the 100lbs force. The red indicates that there

is likely to be buckling near the top of the bezel, but it did not extend across the length of the bezel. The

analysis displays no signs of failure of the mounting clips.

ANALYSIS D

REAR PHONE BEZEL MOUNTING CLIP REDESIGN (VON MISES STRESS ANALYSIS)

FEBRUARY 13, 2017

Results: The analysis displays that the rear bezel is subjected to 21 MPa which is well below the 45 MPa

threshold of Acrylic. Furthermore the simulation shows only 5 MPa on the clips. Elastic properties are

displayed and the phone is not likely to break under 100lbs force.

ANALYSIS E

REAR PHONE BEZEL MOUNTING CLIP REDESIGN (DISPLACEMENT)

FEBRUARY 13, 2017

Results: The displacement analysis displays .003 inches of displacement which is not significant

indicating the clips are not likely to deform.

FREQUENCY ANALYSIS

The purpose of this study was to determine the frequency of horizontal vibration and optimize the

design of a tuning fork to achieving the desired frequency. By changing the geometry and materials of a

model, the designer can avoid critical ranges to prevent failure or extend service life.

The tuning fork initially had a frequency of 440 Hz at a length of 4 inches and I was instructed to

redesign it to have a frequency of 400 Hz. This was achieved with the FEA software by shortening the

tuning fork to 3.792 inches.

THERMAL ANALYSIS

The purpose of this study was to analyze the heat transfer between a 7 Watt output central processing

unit and an aluminum alloy heat sink to determine if the heat sink design was adequate to keep the

processor within operating temperature.

A 7 Watt Heat Power is assigned to the face of the cpu and a fine mesh is created

Contact sets and convection entities are selected

THERMAL ANALYSIS CONTINUED

Results indicate the design of the heat sink would fry the processor at 219 degrees Farenheit

A larger heat sink is applied. The temperature under load stays within an operable 136 degrees Farenheit

COMPUTATIONAL FLUID DYNAMICS

The purpose of this study was to learn to use the flow simulation tools to simulate air passing around a

jet travelling at mach 2 to analyze pressure, temperature and laminar/turbulent flows with cut plots,

surface plots and flow trajectories.

Flow trajectory analysis to visualize airflow of a jet travelling at mach 2

COMPUTATIONAL FLUID DYNAMICS CONTINUED

Cut plot pressure analysis

Surface plot analysis of temperature showing which areas of the aircraft generate the most heat from friction

TOY WHEEL TORQUE ANALYSIS

March 04, 2017

BY: Matthew Rossow

Purpose: The purpose of this study is to evaluate the structural integrity of an engineered design and

determine the elements of potential failure under a torque test with 30 lbs of force.

FEA-Finite Element Analysis software was used to identify undesirable feature characteristics through

computer simulation. This document presents chronologically the process of identification, correction,

and optimization of engineered features.

Material: Acrylic (MPa Threshold 45MPa)

ANALYSIS – A

PLASTIC TOY WHEEL TORQUE ANALYSIS (ORIGINAL DESIGN)

March 04, 2017

Results: The plastic toy wheel appears to be over-engineered. During analysis I found that the wheel

was 6x stronger than the material yield of 45 MPa under 30 lbf torque showing stress of only 7.5 MPa at

the joints. The outside wheel displays less than 2 MPa leading me to believe the internal ribs on the

underside of the wheel are unnecessary.

Summary: PASS. NOTE: OVER-ENGINEERED BY A FACTOR OF 6x AT THE JOINTS

JOINTS UNDER HIGHEST STRESS

ANALYSIS – B

PLASTIC TOY WHEEL TORQUE ANALYSIS (REVISED/OPTIMIZED DESIGN)

March 04, 2017

Results: After reduction in wall thickness from .100 inches to .050 inches and complete removal of all

internal ribs, the part still displays elastic behavior. The joints are subjected to 25 MPa which is still well

below the 45 MPa yield strength.

The test indicates the part is still over engineered, but reducing thickness below .050 inches is not

advised due to the mold process.

Summary: PASS

ANALYSIS – C

STEERING WHEEL DISPLACEMENTANALYSIS (REVISED/OPTIMIZED DESIGN)

March 04, 2017

Results: The wheel shows displacement of only .091 which is acceptable and is not likely to compromise

functionality.

Summary: PASS

MATERIAL COST ANALYSIS

ORIGINAL OPTIMIZED

SUMMARY: I reduced the overall plastic used per part and generated savings of 55% with the new

design without sacrificing the stability or safety of the part under 30lbf torque.

Original weight .20 lbs. Optimized weight .09 lbs.