Work Samples, Pooyan Abbasi

Work Samples

Pooyan Abbasi

M.S. Student

Mechanical Engineering Department

Temple University

Contents • Stress analysis in a 2D square plate with a circular hole

• Femoral broaching

• Falling onto outstretched hand

• 3D printing a horned sand lizard foot with articulating

joints

• Wooden bridge competition

• Simulation of an airbag deployment

• Calibration of hotwire anemometer

Stress analysis in a 2D square plate

with a circular hole

• Stress distribution was solved inside a domain

composed of a rectangle with a circular hole. Due

to symmetry, only a quarter of the physical domain

was solved.


with a circular hole • Effect of different mesh

types (Quadrilateral vs.

triangular) were studied

using Abaqus software

• Comparison of the results to

analytical solution showed

excellent agreement.


with a circular hole • Peak stress was found close

to the corners of the hole

while less stress observed on

the outer edges of the

rectangle.

Femoral broaching

• Femoral broaching is a tool for performing hip arthroplasty.

• Surgeons strike a toothed tool called a broach, into the patients’ femur in order to connect the femur to the artificial joint.

• Several authors have reported an increased rate of intraoperative fracture with this method.

• Our goal was to evaluate 3-dimensional broaching forces and moments brought about by specialized curved implantation handles designed to be used during total hip replacement via the direct anterior approach.

Femoral broaching: Setup • The SolidWorks drawings of the broach were

prepared in order to make a solid model of

the broach.

Femoral broaching: Setup • The solid model of the broach was cut off of

an aluminum block using CNC machine.

Femoral broaching: Setup • The 6 axis force transducer was calibrated

using LabVIEW.

Femoral broaching: Simulations

• Four different handles were studied.


• The impact location of the hammer was studied at 8

different positions on the back of the handles.


• Simulated the impact loads using LS-DYNA


• Analyzed the forces and moments and found the

optimal position for impact positions.


• It was found that depending on the hammering

position, the impact could be successful or may lead

to bone fracture .

Falling onto outstretched hand

• Wrist injuries are common in youth “extreme sports”

such as snowboarding, skateboarding and

rollerblading.

Falling onto outstretched hand

• A prototype wrist guard incorporating a viscoelastic

cushion and a commercially available guard with

rigid volar plate was evaluated.

• In order to test the wrist guards we needed a setup

that applies the same impact force and velocity as if

someone falls on their hand.

Falling onto outstretched hand:

Vertical drop test setup • 5𝑘𝑔 mass was dropped from

0.7𝑚.

• It delivered in

18.5𝑁. sec momentum and

34𝐽 of kinetic energy to the

specimen.

• Forces and moments were

measured using a 3 axis

loadcell.


Vertical drop test setup • Due to friction and losses,

the velocity is less than free

fall velocity. Therefore, The

velocity of the impact was

evaluated using a proximity

sensor and also validated

using high speed camera.

• The data acquisition system

was triggered using the

proximity sensor.


Simulations • Simulated the injury using LS-DYNA.

• Peak forces and maximum angle of wrist extension were

obtained and validated with experimental data.

3D printing a horned sand lizard foot

with articulating joints • When animals run on soft substrates they are usually

slower than when they run on a harder surface.

• Some lizards surprisingly can run with the same speed

on a soft surface like sand as if they were running on a

harder surface such as asphalt.

• The mechanism of this phenomenon is not clear yet.

• We hypothesize that the structure and material

properties of the foot control the speed of the lizard

passively.

• The first step to test this hypothesis was to have model

of the foot to perform intrusion tests on different

materials.

3D printing a horned sand lizard foot

with articulating joints • Created the model from CT scan raw data

• Designed the joints using SolidWorks

Wooden bridge competition • Supervised 2 undergraduate students to understand

basic mechanical concepts. There were 40 participants.

• Helped them design the bridge using 50 popsicles.

• First place winner with ability to resist up to

60𝑙𝑏𝑠 compression load. The second place winner sample

only resisted 40𝑙𝑏𝑠.

Wooden bridge competition • Stress-strain curve of the bridge under

compression load was obtained

experimentally and different points of the

curve were explained to the class.

Simulation of an airbag deployment

• The purpose of this project was to replicate an airbag

deployment system.

• This was done by utilizing a model car, running it down a

track to collide with a wall, and measuring its deceleration

using an accelerometer.

• Acceleration time

history was obtained

and the data was

analyzed using

LabVIEW.

Simulation of an airbag deployment:

data analysis using LabVIEW • Noises in the system may

result in an unnecessary

deployment of the airbag.

• A moving average filter was

developed in LabVIEW to

filter the noise in our data

Calibration of hotwire anemometer

• Hotwire is a measurement tool used to

determine the velocity of fluids

• It maintains its temperature constant by

applying variable voltages to the wire

• From King’s law, we know that:

𝐼2𝑅𝑠 =𝐸2

𝑅𝑠= 𝐴 + 𝐵𝑈𝑛

• Where I is the current, R is the resistance, E

is the voltage and A, B and n are the

calibrations constants that we seek for.


• The calibration was done recording the points in the

wind tunnel to obtain the velocity values.

• A pitot static tube reported the velocities.

• The voltages were collected with Data Acquisition system

connected to the hotwire.

Test # Height (m) Velocity Avg

Voltage E^2/R=A E^2/R - A U

1 0 0 1.340835

8 0.43426102 0.000000 0.000000

2 0.007 10.74299 2.13746 0.43426102 0.669300 11.337020

3 0.012 14.06587 2.18566 0.43426102 0.719627 13.653813

4 0.02 18.15896 2.25553 0.43426102 0.794587 17.604612

5 0.03 22.24010 2.31661 0.43426102 0.862039 21.696072

6 0.044 26.93409 2.37642 0.43426102 0.929844 26.346215

7 0.056 30.38576 2.42337 0.43426102 0.984266 30.484175

8 0.066 32.98739 2.46050 0.43426102 1.028073 34.086119

9 0.074 34.92946 2.47574 0.43426102 1.046241 35.652442

10 0.082 36.76910 2.48666 0.43426102 1.059335 36.808138


• 𝑉𝑜𝑙𝑡𝑎𝑔𝑒2 was plotted against 𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦𝑛. The trend-line

shows the calibration constants.

y = 0.0154x + 0.5101

R² = 0.9961

0.000000

0.200000

0.400000

0.600000

0.800000

1.000000

1.200000

0.00000 5.00000 10.00000 15.00000 20.00000 25.00000 30.00000 35.00000 40.00000

Vo

ltag

e^2

Velocity^n

Best Fit Line for A,B,n

Thank you for your attention

• I would be happy to explain each one of the projects in

further details. If you are interested, please do not

hesitate to contact me for any further information.

Pooyan Abbasi

[email protected]

Tel: 267 357 7155

mailto:[email protected]

mailto:[email protected]

Work Samples, Pooyan Abbasi

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