(ebook) Tutorial - ANSYS Exercise2.pdf

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ANSYS/LS-Dyna CD Book
Exercise 2: PDA Drop Test.
In this exercise, we will perform a drop test of a typical personal digital assistant
(PDA) electronic device. Mobile electronic devices are becoming increasingly
more popular, and the ability of the devices to sustain an impact after being
dropped is important. The PDA used in this analysis is illustrated in the figure
below. The goal of this analysis is to determine if the case will break or the
batteries (C) will be ejected from the device should it suffer a six foot drop onto a
rigid surface.
A: Glass Touch Screen
B: Battery Compartment
C: Batteries
We will start this exercise with a predefined ANSYS database containing the
geometry of the PDA device. This geometry could be imported from any
commercial CAD program using a variety of ANSYS translators supporting all
major geometry formats.
Exercise 2: PDA Drop Test
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Summary of steps:
1. Launch ANSYS/Multiphysics/LS-DYNA:
1.1. Launch ANSYS using your start menu.
2. Setup:
2.1. Resume database.
2.2. Plot model
2.3. Plotting Controls
2.4. Set preferences to Structural LS-Dyna
3. Modeling:
3.1. Element Type Definition
3.2. Real Constants
4. Material Properties:
4.1. Case Material Properties
4.2. LCD Material Properties
4.3. Battery Material Properties
5. Model Attributes:
5.1. Case Attributes
5.2. LCD Screen Attributes
5.3. Battery Cover Attributes
5.4. Battery Attributes
6. Meshing:
6.1. Mesh Batteries
6.2. Mesh PDA
7. LS-Dyna Options:
7.1. Contact Definition
8. Drop Test
8.1. Drop Test Input
9. Solution:
9.1. Save Model
9.2. Perform LS-Dyna Solution
Exercise 2: PDA Drop Test
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10. Post Processing:
10.1. Report Generation
10.2. Von Mises strain animation
10.3. Determine max stress in PDA.
10.4. Determine max stress in LCD display.
10.5. Report Assembly
11. Conclusions:
11.1. Examine Stress and Strain Values
11.2. Exit ANSYS.
Exercise 2: PDA Drop Test
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Step-by-step Instructions:
Before beginning this problem, create a separate folder on your computer for this
job and copy the ANSYS database pda.db to this folder. This file is located on
CD 1 in a folder called Input Files .
1. Launch ANSYS/LS-Dyna
1.1. Launch ANSYS using your start menu.
A. Browse to select the working directory you just created for this job.
B. Enter a job name ( pda1 ). All ANSYS files created for this problem will
have a filename of pda1 allowed by a unique extension.
C. Change the workspace and database sizes for this job to be 512 and
128 respectively.
D. Click RUN to start the ANSYS GUI.
1.1.B
1.1.A
1.1.C
1.1.D
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2. Setup
2.1. Resume database.
A. We will start with an ANSYS database that‘s already been created for
you. This database contains only the geometry of the PDA. In the
ANSYS utility menu, pick File
B. Resume from…
C. Pick the file pda.db which you should have copied to the working
folder from the CD.
D. OK .
E. The model will be loaded into ANSYS and plotted in the graphics
window. Note that by default, ANSYS plots only the solid entities or
“volumes”. For our model, the batteries are the only solid entities. The
PDA device will be modeled with shells or “areas”.
2.1.A
2.1.B
2.1.D
2.1.C
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