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.

Stress analysis in a 2D square plate

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.

Stress analysis in a 2D square plate

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.

Femoral broaching: Simulations

• The impact location of the hammer was studied at 8

different positions on the back of the handles.

Femoral broaching: Simulations

• Simulated the impact loads using LS-DYNA

Femoral broaching: Simulations

• Analyzed the forces and moments and found the

optimal position for impact positions.

Femoral broaching: Simulations

• 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.

Falling onto outstretched hand:

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.

Falling onto outstretched hand:

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.

Calibration of hotwire anemometer

• 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

Calibration of hotwire anemometer

• 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

abbasi.pooyan@temple.edu

Tel: 267 357 7155