Tài liệu CATIA V5 Structural Analysis for the Designer P2 doc

Use a rough analysis to determine where the high stress areas exist that will require additional mesh refinement... Select the Pedal “Part” representation in the features tree.. Apply s

100 lbs

100 lbs

Elastic Modulus, E 29.0E6 psi Poisson’s Ratio, ν 0.3

Density 284 lb/in3 Yield Strength 36,000 psi

WORKSHOP 3 – BICYCLE PEDAL STATIC ANALYSIS

„ Problem Description

‹ Your job will be to analyze various components of a mountain bicycle We will start with the pedal.

‹ Let’s assume a 200 lb person riding this bike is standing, balanced evenly on each pedal Material (Steel) properties as specified

below Use a rough analysis to determine where the high stress areas exist that will require additional mesh refinement.

„ Suggested Exercise Steps

1 Open the existing CATIA part in the Part Design workbench.

2 Apply steel material properties to the part.

3 Create a new CATIA analysis document (.CATAnalysis).

4 Pre-process initial finite element mesh.

5 Apply a clamp restraint.

6 Apply a distributed force.

7 Compute the analysis.

8 Visualize the analysis results.

9 Save the analysis document.

WORKSHOP 3 – BICYCLE PEDAL STATIC ANALYSIS

Open the CATIA part

ws3pedal.CATPart in

the Part Design

workbench

Steps:

1 Select File and

Open… from the top

pull-down menu

2 Access the class

workshop directory

using the typical

Windows interface

3 Open the pedal by

double-clicking

By default, the pedal

and all other CATPart

documents are

opened in the Part

Design workbench

Step 1 Open the existing CATIA part

1 2

3

Step 2 Apply steel material properties to the part

Before every session

you should verify your

session units

Steps:

1 Select Tools from

the menu then

Options

2 Select the General

category then

Parameters

3 Select “Units” tab,

change all units to the

English system

Notice there are many

variables accessed by

a scroll bar, verify and

edit until all units are

consistent You must

change each one

separately, select OK

1

3 2

Step 2 Apply steel material properties to the part

3

2

4

Steps:

1 Select the Pedal

“Part” representation

in the features tree

2 Click the Apply

Material icon

3 Activate the Metal

tab in the Library

window

4 Select Steel.

5 Make sure Link to

file is selected, then

select OK

6 Make certain

material is applied

properly in the

features tree

6 1

5

Step 2 Apply steel material properties to the part

4 3

5

Verify and edit

structural material

properties and activate

material rendering

Steps:

1 Right click Steel in

the features tree

2 Select Properties.

3 Select Analysis tab.

4 Verify and edit

structural material

properties here, select

OK

5 Click the

Customized View

Parameters icon to

activate custom view

material rendering

1

2

Step 3 Create a new CATIA analysis document

1

3

4

Steps:

1 From the Start

menu select the

Analysis & Simulation

then the Generative

Structural Analysis

workbench

2 Select Static

Analysis, select OK

3 Your Static Analysis

document gets

automatically linked to

the CATPart

4 Note the Material

Property 3D.1

previously specified in

the CATPart document

shows up here in your

CATAnalysis

document

2

Step 3 Create a new CATIA analysis document

Specify the External

Storage directory

locations

Steps:

1 Select the Storage

Location icon

2 In the Current

Storage Location

modify the Results

Data location and

rename as shown

3 In the Current

Storage Location

modify the

Computation Data

location and rename

as shown, select OK

4 Note the Links

Manager in the

features tree reflects

the paths

You can create

specific directories for

additional

organization

4

1 2

3

Step 4 Pre-process initial finite element mesh

Define the global finite

element mesh

properties

Steps:

1 Double Click the

“OCTREE

Tetrahedron

Mesh.1:Pedal”

representation in the

features tree or the

“Mesh” icon on the

part

2 Specify the

recommended rough

Global Size = 25”

3 Specify the

recommended Sag =

10% of Global Size

4 Specify element

type “Linear” (TE4,

means 4 node

tetrahedron) and is

good for a rough

analysis, select OK

2 1

3 4

Step 5 Apply a clamp restraint

Steps:

1 Select the Clamp

Restraint

icon

2 Select the shaft that

attaches to the crank

3 Select OK.

4 Note the Clamp

object added to the

features tree

1

4

3

2

Step 6 Apply a distributed force

Steps:

1 Select the Force

icon

2 Select the 3 outside

foot grip pads

3 Enter -100 lbs in the

Z-direction, select OK

4 Note the Distributed

Force object added to

the features tree

2

3

1

4

Step 7 Compute the analysis

1 2

Steps:

1 Select the Compute

icon

2 Compute All Objects

defined, select OK

3 Notice the estimated

time, memory, disk

requirement and

Warning for decreasing

computation time

-select Yes to continue

4 This symbol

indicates

computation required

3 4

Preview active

Step 8 Visualize the analysis results

Visualize the finite

element mesh in the

deformed state of the

system as a result of

loading

Steps:

1 Select the

Deformation Image

Icon

2 Note the Deformed

Mesh Image added to

the features tree

2

1

Step 8 Visualize the analysis results

1

Visualize the Von

Mises stress which is

a combination of all

primary and principal

stresses

Steps:

1 Select the Stress

Von Mises icon

2 Note the Image

Deactivated symbol for

the Deformed Mesh

image

2

Step 8 Visualize the analysis results

1

Visualize the

displacement

vectors

Steps:

1 Select the

Displacement

icon

2 Right mouse click

Transl displacement

vector in the tree

3 Select Definition.

4 Select Visu tab.

5 Note by default

SYMBOL is selected,

select OK

2

4

5 3

Visualize the

displacement field

patterns using the

AVERAGE-ISO

definition

Steps:

1 Right click

Translational

displacement vector in

the features tree

2 Select Definition.

3 Select Visu tab.

4 Select

AVERAGE-ISO, select OK

Step 8 Visualize the analysis results

4 2

Add additional image

smoothing options to

the AVERAGE-ISO

visualization definition

Steps:

1 In the Image Edition

window, select the

Iso/Fringe button

2 Select the box for

ISO smooth

3 Select OK.

4 Select OK.

Transitions between

colors on the image

display are blended

Step 8 Visualize the analysis results

1

4

2

3

Step 8 Visualize the analysis results

Visualize the

computation error

which represent scalar

field quantities defined

as the distribution of

energy error norm

estimates for a given

computation

Steps:

1 Select the

Precision icon

2 Double click on the

Estimated local error

color map palette

3 Select Impose Max

for the color map

palette, select OK

4 Select the

Informations

icon

5 Then select in the

features tree

Estimated local error

3

4

5

2

1

„ Conclusions

‹ You now know where the “hot spots” are but the stress and displacement results are questionable with a 43.5% Global Precision Error

‹ The next step is to refine the mesh in the critical areas We will go over this in the next workshop #4.

Step 8 Visualize the analysis results

.25” Linear Mesh Max Von Mises 24.6 ksi

Translational Displacement 00407 inch Error Estimate 8.65e-8 Global % Precision error

Local % Precision error

43.5 %

NA %

Recommendation Error Estimate 1.00e-8 (zero) Global % Precision error

Local % Precision error

20 %

10 %

Step 9 Save the analysis document

Steps:

1 From the File menu

select Save

Management

2 Select document

you want to save

3 Select Save As to

specify name and

path, select OK

The pedal.CATPart

and CATAnalysis

should each be saved

under a new name in

the work directory

1