MAR101_Exercises

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Introduction to MSC.MARC and MENTAT

January 2004

DISCLAIMER

MSC.Software Corporation reserves the right to make changes in specifications and other information contained in this document without prior notice.

The concepts, methods, and examples presented in this text are for illustrative and educational purposes only, and are not intended to be exhaustive or to apply to any particular engineering problem or design. MSC.Software Corporation assumes no liability or responsibility to any person or company for direct or indirect damages resulting from the use of any

information contained herein.

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TABLE OF CONTENTS

Workshop

No.

Linear and Nonlinear Analysis of a Cantilever Beam Ö Ö Ö Ö Ö Ö Ö ..Ö Ö Ö Ö Ö Ö ..Ö ...Ö Ö 1-1

Analysis of a Rubber Seal Ö Ö Ö Ö Ö Ö Ö Ö ..Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö .Ö Ö Ö Ö Ö Ö .Ö Ö Ö 2-1

Pin Insertion and Extraction Ö Ö Ö Ö Ö Ö Ö Ö Ö .Ö Ö Ö Ö Ö ..Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö ..Ö Ö Ö 3-1

Necking of a Test Specimen Ö Ö Ö Ö Ö Ö Ö .Ö .Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö ..Ö Ö Ö 4-1

Steady State heat Transfer Ö .Ö Ö Ö Ö Ö Ö Ö Ö Ö .Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö ..Ö Ö .. 5-1

Hertz Contact Analysis Ö ..Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö .Ö Ö .. 6-1

Metal Forming of a BracketÖ Ö Ö Ö Ö Ö ..Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö .Ö Ö .Ö Ö Ö . Ö Ö .. 7-1

3-D Contact between Telescoping Pieces .Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö ..Ö Ö Ö . 8-1

Transient Heat Transfer Analysis Ö ...Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö ..Ö ... 9-1

Soft-Drink Canís Bottom Snap-Through Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö ..Ö Ö Ö Ö Ö ...Ö Ö Ö Ö Ö Ö 10-1

Creep of a Steel Tube Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö ..Ö Ö Ö Ö . 11-1

Composite Laminate Telescope Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö .. 12-1

Normal Modes, and Linear transient Analysis of a Box Beam Ö Ö Ö Ö Ö Ö Ö Ö Ö .Ö Ö Ö Ö .. 13-1

Buckling Analysis of a Box Beam Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö ..Ö ..Ö ... 14-1

Interference Fit of two concentric Cylinders Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö .. 15-1

Experimental Hyperelastic Data Fitting Ö Ö Ö Ö Ö Ö Ö Ö Ö Ö ..Ö Ö Ö Ö Ö Ö Ö Ö Ö .Ö Ö Ö ... 16-1

WORKSHOP 01

LINEAR AND NONLINEAR

Section A-A

b

a

(Data in next page)

ƒ

Problem Description

‹

In this exercise, a cantilever beam is subjected to a

static load. The beam is initially analyzed using small

deformation theory. However, after reviewing the

results, it becomes apparent that small deformation

theory is not appropriate for this problem.

Subsequently, a large deformation analysis is

performed and its results are compared to the small

deformation analysis.

0.3

30.0 x 10

_lb/in

2.0 in

1.0 in

100.0 in

0.3

207 GPa

50.8 mm

25.4 mm

2.54 m

Poissonís Ratio

Youngís Modulus

b

a

Length, L

b

a

ƒ

Problem Description (cont.)

Š

The model is made using eight, 2D plane stress, assumed

strain, reduced integration (type 114) elements. The elements

are uniformly spaced along the length of the beam (i.e. a mesh

eight elements wide and one element deep). The assumed

strain, reduced integration element is designed specifically for

in-plane bending and is well suited for this problem.

ƒ

Objectives:

Š

Small vs. large displacement analysis.

Š

Linear elastic theory

ƒ

Required

ƒ

Suggested Exercise Steps:

1. Create simple Cantilever model as illustrated

2. Use a simple, elastic steel material

3. Run a linear analysis with default setup.

4. Run a nonlinear analysis with default setup.

5. Compare results.

Step 1. Exercise Procedure

Open a new database named

Tip_load.db

a. Click FILES. b. Click SAVE AS. c. Type SELECTION: <work_directory>\tip_load d. Click OK. e. Click RETURN.

a

c

d

b

[Enter] means clicking on that keyboardís key (ìcarriage returnî). RETURN refers to MSC.Marc Mentatís button with such label (below).

Step 2. Mesh Generation: Add / Pts / Point Coordinates

Create points to define a surface

a. Click MESH GENERATION. b. Click PTS ADD.

c. Enter point coordinates (X) : 0 [Enter]. d. Enter point coordinates (Y) : 0 [Enter]. e. Enter point coordinates (Z) : 0 [Enter]. f. Repeat steps b-e for three additional

points: g. Click FILL.

a

b

c

d

e

f

The point coordinates may be entered together using spaces or commas as in:

100 0 0 [Enter]

or in:

To enter data values or names, simply click on the desired icon, and enter the values or names in the command panel and then hit

Step 3. Mesh Generation: Add / Srfs / Quad

Create the surface from the four points defined

a. Click SURFACE TYPE. b. Click QUAD.

c. Click RETURN (or press the

mouseís right button).

d. Click SRFS ADD.

a

b

c

d

With the cursor placed anywhere inside the Vertical Menu area, pressing the mouseís right button is equivalent to clicking on Mentatís

e. Enter quad points : 1 2 3 4 [Enter]

The surface will be created when you press [Enter] and should look like the one here.

Step 4. Mesh Generation: Convert / Surfaces to Elements

Create mesh elements

a. Click ELEMENT CLASS. b. Select QUAD (4).

c. Click RETURN.

a

b

d. Click CONVERT. e. Click DIVISIONS.

f. Enter the number of convert divisions in U and V : 8 1 [Enter].

d

g. Click SURFACES TO

ELEMENTS.

h. Select surface 1 (ensure DYN. MODEL is deselected).

i. Click END LIST (#). j. Click MAIN.

h

The mesh surface will be created when you click END LIST (#).

i

j

g

When selecting (picking) a list of fem or

geometric entities, pressing the mouseís

right button (with the cursor anywhere

inside the viewport) is equivalent to clicking on Mentatís END LIST (#)

Step 5. Material Properties: New / Isotropic

Create material property for steel

a. Select MATERIAL PROPERTIES. b. Click NAME.

c. Enter material name : steel [Enter]..

b

c

a

d. Click ISOTROPIC.

e. Click YOUNGíS MODULUS.

f. Enter value for ëyoungs_modulusí :

30e6 [Enter].

g. Enter for ëpoissons_ratioí :

0.3 [Enter].

h. Enter value for ëmass_densityí :

0.00074 [Enter]. i. Click OK.

d

f

e

i

a

Step 6. Material Properties: New / Isotropic

Assign material properties to the geometry

a. Click ELEMENTS ADD. b. Select all elements (ensure

DYN. MODEL is deselected). c. Click END LIST (#).

d. Click MAIN.

j

h

c

Step 7. Geometric Properties: New / Planar / Plane Stress

Create 2D geometric properties

a. Click GEOMETRIC

PROPERTIES.

b. Select PLANAR.

c. Click PLANE STRESS. d. Click THICKNESS.

e. Enter value for ëthickí : 1 [Enter]. f. Select ASSUMED STRAIN. g. Click OK.

h. Click NAME.

i. Enter geometry property name :

beam_geom [Enter].

j. Click ELEMENTS ADD.

e

a

b

d

f

g

l

k. Select all elements. l. Click END LIST (#). m. Click MAIN.

c

Step 8. Boundary Conditions: New / Mechanical / Fixed Displacement

Create fixed B.C. on the left edge of model a. Select BOUNDARY CONDITIONS. b. Select MECHANICAL. c. Click FIXED DISPLACEMENT. d. Check ON for DISPLACEMENT X DISPLACEMENT Y e. Click OK.

a

b

d

e

f. Click NODES ADD. g. Select left edge nodes. h. Click END LIST (#). i. Click NAME.

j. Enter boundary condition name : fixed [Enter].

f

i

g

a

b

f

Step 9. Boundary Conditions: New / Mechanical / Point Load

Create a load to apply to the right edge of model

a. Click NEW.

b. Click POINT LOAD. c. Select FORCE Y ON. d. Enter value for ëyí :

ñ3000 [Enter].

e. Click OK. f. Click NAME.

g. Enter boundary condition name :

tip_load [Enter].

d

e

c

h. Click NODES ADD . i. Select right edge nodes. j. Click END LIST (#). k. Click MAIN.

h

Step 10. Loadcases: New / Mechanical / Static

Create the loadcase

a. Click LOADCASES. b. Click MECHANICAL. c. Click STATIC.

a

c

b

d. Click LOADS.

e. Ensure that both fixed and

tip_load loads are selected

(ON). f. Click OK.

d

g

i

g. Click # STEPS.

h. Enter loadcase parameter value : 1 [Enter].

i. Click OK.

j. Click NAME.

k. Enter loadcase name :

my_linear [Enter].

l. Click MAIN.

j

Step 11. Jobs: New / Mechanical

Create the analysis job

a. Click JOBS.

b. Click MECHANICAL.

c. Click ANALYSIS OPTIONS.

b

a

d. Select LINEAR ELASTIC

ANALYSIS.

e. Click ADVANCED OPTIONS. f. Select CONSTANT

DILATION.

g. Select ASSUMED STRAIN. h. Click OK.

f

d

i. Click OK.

j. Select my_linear LOADCASE.

k. Select PLANE STRESS. l. Click OK.

j

k

l

m. Click ELEMENT TYPES. n. Click MECHANICAL. o. Click PLANE STRESS.

m

n

o

p. Click 114 (4-Node Quad. with reduced Integration). q. Select all elements. r. Click END LIST (#). s. Click OK. t. Click MAIN.

q

p

s

r

t

a

Step 12. Jobs: New / Mechanical

Run the linear analysis

a. Click JOBS. b. Click NAME. c. Enter job name :

linear_job1 [Enter].

d. Click RUN.

b

d

c

e

f

g

e. Click SAVE MODEL. f. Click SUBMIT (1). g. Click MONITOR.

h. Click STATUS FILE after ìCompleteî appears in STATUS box. i. Click OK. j. Click MAIN.

h

a

Step 13. Results: Open Default / Monitor / Def & Orig

Plot linear analysis results

a. Click RESULTS.

b. Click OPEN DEFAULT. c. Click DEF & ORIG. d. Click SCALAR. e. Select Displacement Y. f. Click OK.

e

b

c

d

g. Select CONTOUR BANDS. h. Click FILL.

g

h

( )

( )

( ) ( )

( )

( )

2

900

,

000

1

100

000

,

6

6

6

100

2

1

10

30

100

000

,

6

4

3

=

×

×

×

=

=

×

=

=

×

×

×

×

=

×

=

=

σ

σ

b

a

PL

I

b

M

U

ab

E

PL

EI

PL

U

The maximum Y deflection of the beam can be read directly from the displayed spectrum/range. The largest value corresponds to a magnitude of 99.64, which is in fair agreement with a manual calculation of 100. You may still improve this by remeshing using two elements over the high of the section instead of just one as you have it now. (You will be asked to do this after you have run a nonlinear analysis using the present mesh.)

Linear beam theory assumes plane section remain plane and the deflection is small relative to length of the beam. As can be clearly seen by this analysis, the deflection is very large and this analysis is in violation of the underlying assumptions used for linear beam theory.

These results match the linear hand calculations and also show that the small deformation assumption is not valid and therefore, a non-linear, large deformation analysis needs to be performed. In large deformation analysis, the bending and axial stiffness are coupled. Thus, as the cantilever beam deflects, a portion of the load P puts the beam in tension which tends to stiffen the beam in bending (i.e. ìgeometric stiffnessî). Thus, one would expect to see a much smaller deformation in the large deformation analysis as compared to the small deformation analysis. To set up a large deformation analysis, one needs to change the analysis set-up and re-submit the job to MSC/ MARC

Linear beam theory predicts the maximum beam deflection in the Y-direction and stress to be:

Step 14. Loadcases: New / Mechanical / Static

f. Enter loadcase name :

my_nonlinear [Enter]. g. Click MECHANICAL. h. Click STATIC.

h

a

d

e

g

c

i

l

m

i. Click LOADS.

j. Ensure that both fixed and

tip_load loads are selected

(ON). k. Click OK.

l. Select MULTI CRITERIA. m. Click PARAMETERS.

j

n. Click MAXIMUM FRACTION

OF LOADCASE TIME.

o. Enter loadcase parameter value : 0.04 [Enter]. p. Click OK.

n

p

q. Click SOLUTION CONTROL. r. Select NON-POSITIVE DEFINITE. s. Click OK. t. Click OK. u. Click MAIN.

q

t

r

s

Step 15. Jobs: New / Mechanical

Create a nonlinear analysis job

a. Select JOBS. b. Click NEW. c. Click NAME. d. Enter job name :

nonlinear_job1 [Enter].

e. Click MECHANICAL. f. Select my_nonlinear

loadcase.

g. Click INITIAL LOADS.

c

b

e

a

f

g

h. Deselect fixed initial load.

i. Deselect tip_load initial load. j. Click OK. k. Click ANALYSIS OPTIONS.

h

j

i

k

l. Select LARGE

DISPLACEMENT.

m. Select FOLLOWER FORCE. n. Select LARGE

STRAIN-TOTAL LAGRANGE.

o. Select LARGE STRAIN

ADDITIVE.

p. Click ADVANCED OPTIONS. q. Select CONSTANT

DILATATION and ASSUMED STRAIN. r. Click OK. s. Click OK.

l

m

n

o

p

s

t. Select PLANE STRESS. u. Click OK. v. Click MAIN.

t

u

v

b

Step 16. Jobs: New / Mechanical

Run the nonlinear analysis

a. Click JOBS b. Click RUN.

d

c

e

c. Click SAVE MODEL. d. Click SUBMIT (1). e. Click MONITOR.

f. Click STATUS FILE after ìCompleteî appears in STATUS box. g. Click OK. h. Click MAIN.

f

a

Step 17. Results: Open Default / Monitor / Def & Orig

Plot nonlinear analysis results

a. Click RESULTS.

b. Click OPEN DEFAULT. c. Click LAST.

d. Click DEF & ORIG. e. Click SCALAR. f. Select Displacement Y. g. Click OK.

f

b

c

d

e

h

h. Select CONTOUR BANDS. i. Click FILL.

Step 18. Compare Your Results

■

Compare the results

◆

Obtain the maximum Y deflection from the contour band plot. Enter

that value into the table below.

MSC/MARC

Small Deflection

Large Deflection

Enter your results (8x1 mesh)

MSC/MARC

Theory

-100.0

Small Deflection

Large Deflection

-99.64

Compare with these (8x1 mesh)

-58.81

-58.59

Note the horizontal displacement in the nonlinear solution As shown in the results obtained, inclusion of large

deformation effects are very important in realistically modeling the physical behavior of the cantilever model.

Why do we ask you to have half the load on the center node and a quarter of the load on each corner node ?

Each of the two elements connected to the center node contributes the same stiffness to the center node as it

contributes to the corner node each is attached to.

Step 19. Improve the Results

„

As a final step, do the following:

1.

Close the existing results.

Delete the existing mesh.

3.

Create a new mesh that has the same number of

elements lengthwise but has two elements over

the height of the beam.

4.

Modify the tip load so that the load in the center

node is still 3000 while the load on each corner

node is 1500 (for the same total of 6000 you had

before).

MSC/MARC

Small Deflection

Large Deflection

Enter your new results (8X2 mesh)

6.

Attach the result files and make quick

plots as before. Compare the

Y-displacements with the ones obtained

with the coarser (8x1) mesh, and the

theoretical values.

When you are done working with this model

a.

Click on

WORKSHOP 2

„

Model Description:

‹

In this exercise we analyze a trunk door seal. The purpose of the

analysis is to examine the stresses and deflections created during

the closing of a door. The seal is made of a rubber material and

therefore will be modeled using hyperelastic material properties.

The trunk door is considered very stiff relative to the rubber seal and

can therefore be modeled using a rigid body.

„

Objectives:

‹

Large displacement/ Large strain analysis

‹

Contact analysis using a rigid body contact

‹

Hyperelastic material model

„

Required:

‹

A file named rubber.igs in your working directory (Ask your instructor

for it if you donít see it before starting.)

„

Suggested Exercise Steps:

1.

Import the seal geometry from an IGES file.

Model the contact surfaces with LBC contact.

Create the element properties.

4.

Create the Loads and BCs.

Submit the job to analysis.

Evaluate the results.

b

Import the IGS file.

a. Open FILES Menu.

b. Click INTERFACES IMPORT. c. Click IGES.

d. Select rubber.igs. e. Click OK.

f. Click RETURN.

Step 1. Files: Import / Iges

a

f

c

In this document:

[Enter] means clicking on that keyboardís

Step 2. Files: Save As

Open a new database. Name it

Rubber.

a. Click SAVE AS. b. Type SELECTION:

<work_directory>\rubber

c. Accept name and close the form by clicking OK. This action actually creates a database file.

d. Click RETURN.

c

b

a

With the cursor placed anywhere inside the Vertical Menu area, pressing the mouseís right button is equivalent to clicking on Mentatís RETURN.

Step 3. Mesh Generation: Convert / Surfaces to Elements

Create mesh for the model.

a. Click MESH GENERATION. b. Select CONVERT.

c. Click DIVISIONS,

d. Enter the number of convert divisions in U and V :

8 20 [Enter].

e. Click SURFACES TO

ELEMENTS.

f. Select the surface shown in the picture and right click to

end list.

b

c

e

f

a

When creating a list of fem or

geometric entities, pressing the

mouseís right button (with the cursor anywhere inside the viewport) is equivalent to clicking on Mentatís END

g. Click DIVISIONS.

h. Enter the number of convert divisions in U and V :

20 8 [Enter].

i. Click SURFACES TO

ELEMENTS.

j. Select the surface shown in the picture and right click to end list.

k. Click DIVISIONS.

l. Enter the number of convert divisions in U and V :

8 120 [Enter].

m. Click SURFACES TO

ELEMENTS.

n. Select the surface shown in the picture and right click to end list.

o. Right click on left panel to

return.

g

i

j

k

m

n

Notice that when the DYN.MODEL feature is ON you cannot select (pick) entities from the viewport

Step 4. Mesh Generation: AutoMesh / Apply Crv Divs

Create automesh for the surface. a. Back in the MESH

GENERATION menu,

select AUTOMESH.

b. Select CURVE DIVISIONS. c. Click # DIVISIONS.

d. Enter the division number:

130 [Enter].

e. Click APPLY CURVE

DIVISIONS.

f. Select the very bottom curve (curve 5) and right click to end list.

a

c

g. Click # DIVISIONS.

h. Enter the division number:

10 [Enter].

i. Click APPLY CURVE

DIVISIONS.

j. Select the curves shown in the picture (curves 12 and 6) and

right click to end list.

k. Click # DIVISIONS.

l. Enter the division number:

50 [Enter].

m. Click APPLY CURVE

DIVISIONS.

n. Select the curves shown in the picture (curves 11 and 7) and

right click to end list.

g

i

j

m

k

n

l

h

o. Click # DIVISIONS.

p. Enter the division number:

60 [Enter].

q. Click APPLY CURVE

DIVISIONS.

r. Select the curve shown in the picture (curve 9) and right

click to end list.

s. Click # DIVISIONS.

t. Enter the division number:

8 [Enter].

u. Click APPLY CURVE

DIVISIONS.

v. Select the curves shown in the picture (curves 10 and 8) and

right click to end list.

s

u

q

o

p

t

y

aa

x. Click 2D PLANAR MESHING. y. Select QUAD MESH!

z. Select the curves shown in the

picture (curves from 5 thru 12) and right click to end list. In a few seconds you will see a mesh generated in the area enclosed by the selected curves.

aa.Click MAIN.

x

Step 5. Mesh Generation: Sweep / All

Remove duplicated nodes.

a. Click MESH GENERATION. b. Click SWEEP.

c. Select ALL. d. Click MAIN.

c

a

j

Step 6. Boundary Conditions: New / Mechanical / Fixed Displacement

Create Boundary Conditions. a. Click BOUNDARY

CONDITIONS.

b. Click NEW. c. Click NAME.

d. Enter boundary condition name: base-fix [Enter]. e. Select MECHANICAL. f. Click FIXED DISPLACEMENT. g. Check DISPLACEMENT X, and DISPLACEMENT Y. h. Click OK.

i. Click NODES ADD.

j. Select all the nodes at the very bottom of the model and end list by clicking

mouse right button (Try

using ZOOM IN function). k. Return to the main menu

a

g

h

f

i

b

e

c

d

f

j

e

c

b

Step 7. Material Properties: New / Mooney

Create Material Properties. a. Click MATERIAL

PROPERTIES.

b. Click NEW. c. Click NAME.

d. Enter material name:

rubber [Enter].

e. Click MECHANICAL MATERIAL TYPES: MORE.

f. Click MOONEY. g. Click C10.

h. Enter value for ëc10í:

80 [Enter] and

Enter value for ëc01í:

20 [Enter]

i. Click OK.

j. Click ELEMENTS ADD. k. Click ALL EXIST.

l. Click MAIN.

a

g

f

k

j

l

Step 8. Geometric Properties: New / Planar / Plane Strain

Create Geometric Properties. a. Click GEOMETRIC

PROPERTIES.

b. Click NEW. c. Click NAME.

d. Enter geometry property name:

seal [Enter].

e. Select PLANAR.

f. Select PLANE STRAIN. g. Click THICKNESS. h. Enter value for ëthickí:

1 [Enter].

i. Click OK.

j. Click ELEMENTS ADD. k. Click ALL EXIST.

l. Click MAIN.

e

c

b

a

g

i

d

g

a

Step 9. Contact: New / Contact Bodies / Rigid

Create Contact bodies. a. Click CONTACT. b. Click CONTACT

BODIES.

c. Click NEW. d. Click NAME.

e. Enter contact body name: door [Enter] f. Select RIGID. g. Select VELOCITY

PARAMETERS.

h. Click VELOCITY X. i. Enter value for ëvxí:

ñ0.08 [Enter] and

Enter value for ëvyí:

ñ0.8 [Enter].

j. Click OK. k. Click OK.

l. Click CURVES ADD. m. Select all three curves

on the top (curves 4, 1, and 3) and right

click to end list.

n. Click FLIP CURVES. o. Select all three curves

on the top and right

e

h

b

l

f

d

c

n

p. Turn ID CONTACT ON q. Click NEW.

r. Click NAME.

s. Enter contact body name:

rubber [Enter

]

t. Select DEFORMABLE. u. Click OK.

v. Click ELEMENTS ADD. w. Click ALL EXIST.

x. Click MAIN.

s

The rigid body markers must be directed towards the inside of the

rigid body bounded by the curves

representing it.

u

w

v

t

r

q

x

p

b

a

Step 10. LoadCases: New / Mechanical / Static

Create Load Cases.

a. Click LOADCASES. b. Click NAME.

c. Enter loadcase name:

close_door [Enter]. d. Select MECHANICAL. e. Select STATIC. f. Select MULTI-CRITERIA. g. Click PARAMETERS.

e

f

g

q

h. Click MAXIMUM FRACTION

OF LOADCASE TIME.

i. Enter loadcase parameter value: 0.1 [Enter].

j. Click TIME STEP SCALE

FACTOR.

k. Enter loadcase parameter value: 2 [Enter].

l. Select AUTOMATIC

CRITERIA

m. Click # CUT BACKS

ALLOWED.

n. Enter loadcase parameter value: 5 [Enter]. o. Click OK. p. Click OK. q. Click MAIN.

h

i

k

l

j

o

m

Step 11. Jobs: New / Mechanical / Static

Create Jobs. a. Click JOBS.

b. Select MECHANICAL. c. Select close_door. d. Select PLANE STRAIN. e. Click JOB RESULTS.

b

a

e

d

f. Select TOTAL STRAIN. g. Click OK.

h. Click ANALYSIS OPTIONS. i. Select LARGE

DISPLACEMENT.

j. Cycle through selection and select LARGE

STRAIN-TOTAL LAGRANGE.

k. Cycle through selection and select LARGE STRAIN

ADDITIVE. l. Click OK. m. Click OK.

h

m

f

i

l

k

j

n

n. Click ELEMENT TYPES. o. Select MECHANICAL. p. Select PLANE STRAIN

SOLID.

q. Select 118. r. Click OK.

s. Click ALL EXIST. t. Click RETURN twice.

q

o

s

t

p

u. Click RUN.

v. Click SAVE MODEL w. Click SUBMIT (1)

x. Click MONITOR (to monitor the status while the program is running.)

y. Once the program is completed, click OK. z. Click MAIN.

u

z

x

v

w

y

a

Step 11. Results: Open Default / Monitor / Def Only

Check the results:

a. Select RESULTS. b. Click OPEN DEFAULT. c. Click DEF ONLY.

d. Click CONTOUR BANDS. e. Click SCALAR.

f. Select EQUIVALENT TOTAL

STRAIN. g. Click OK. h. Click MONITOR.

d

e

c

b

h

When you are done working with this model

a.

Click on

b.

then click on

WORKSHOP 3

■

Model Description

◆

This is a representative pin-clip ensemble of the sort widely used in

various industries to attach separate components. Typically it is

desired that the material remain in the elastic range and that the

inserting force be smaller than the extracting force to facilitate the

assembly and make an accidental dismembering difficult. The pin

(shaped like a key) is pushed into and then pulled out of a clip

attached to a wall.

■

Objective

◆

Resolving a difficult-to-converge problem.

◆

Plot Insertion and Extraction Forces over the load history.

Resolving snap-contact with static analysis.

■

Required

◆

A file name pin_insert.dat in your working directory (Ask your

■

Suggested Exercise Steps

1.

Import mesh from a MARC .dat file.

2.

Create MPC to apply load/BCs to single nodes for easy reaction

force recovery.

3.

Define materials and properties.

4.

Setup separate Insertion and Extraction load steps.

5.

Setup analysis with appropriate options as advised for job to

converge.

6.

Run and monitor analysis.

7.

Import and post-process results.

■

Reference

◆

Nonlinear Analysis of a Pin Insertion, by Sergio Adeff,

Proceedings Abaqus Usersí Conference, Newport, Rhode Island,

1998.

CREATE NEW DATABASE

Open a new database. Name it

Pin_Insert

a. Open FILES Menu b. Click SAVE AS. c. Type SELECTION:

<work_directory>\Pin_Insert

d. Accept name and close the form by clicking OK. This action actually creates a database file. e. Click RETURN.

a

b

c

Import the neutral mesh file. a. Open FILES Menu.

b. Click INTERFACES IMPORT. c. Click MARC INPUT.

d. Select pin_insert.dat. e. Click OK.

f. Click RETURN. g. Click MAIN. h. Click FILL.

Step 1. Files / Import

b

f

c

d

With the cursor placed anywhere inside the Vertical Menu area, pressing the mouseís right button is equivalent to clicking on Mentatís RETURN.

h

a

Step 2. Links: Add Ties / Nodes / N to 1 Ties

Create the links.

a. Open LINKS Menu. b. Click NODAL TIES. c. Click N TO 1 TIES.

a

b

When selecting (picking) a list of fem

or geometric entities, pressing the

mouseís right button (with the cursor anywhere inside the viewport) is

equivalent to clicking on Mentatís END

LIST (#)

Notice that when the DYN.MODEL feature is ON you cannot select (pick) entities from the viewport

d

d. Click NODE 1. e. Select the retained

(independent) node.

f. Click ADD TIES.

g. Select linked (dependent)

nodes.

h. Right Click to end list.

Make sure that you selected the correct nodes when you Make sure that the

TYPE reads 100. Retained node

Linked nodes

The links will show as pink markers radiating from Node 1630.

e

i. Click NODE 1. j. Select retained

(independent) node.

k. Click ADD TIES.

l. Select linked (dependent)

node.

m. Right Click to end list.

Retained node

Linked nodes

j

l

n. Click NODE 1. o. Select retained

(independent) node.

p. Click ADD TIES.

q. Select linked (dependent)

node. (select all around) r. Right Click to end list.

s. Click MAIN. The purpose of using links is to move the key towards and then away the clip using a single node (there is a node 1629 in the center of the keyhole). This will allow us to later recover the driving force (and the driving pair) which is an essential feature of a pin insertion and extraction design.

Similarly the other two links (MPCs) already created allow the

s

o

q

n

p

Step 3. Material Properties: New / Isotropic / Add Elements

Create the material property for the clip bottom.

a. Open MATERIAL PROPERTIES Menu.

b. Click NAME.

c. Enter material name :

clip_bottom [Enter].

d. Click ISOTROPIC.

e. Click YOUNGíS MODULUS. f. Enter value for

ëyoungs_modulusí : 4600

[Enter].

g. Click POISSONíS RATIO. h. Enter value for ëpoissons_ratioí :

0.33 [Enter].

i. Click MASS DENSITY.

j. Enter value for ëmass densityí:

1e-006 [Enter].

To enter data values or names, simply click on the desired icon, and enter the values or names in the command panel and then hit

[Enter] on your keyboard.

a

e

g

i

b

d

c

l. Click ELEMENTS ADD. m. Select the elements in the

bottom part of the clip. (they are colored in purple in the model shown)

n. Right Click to end list. o. Click ID MATERIAL. (this

action will show if you have selected the right elements)

For better view, click PLOT form the bottom menu, then click SOLID under ELEMENTS. Lastly, click REGEN to create a better image.

These are the elements

o

l

n

m

p. Click NEW. q. Click NAME.

r. Enter material name :

Clip_top [Enter].

s. Click ISOTROPIC.

t. Click YOUNGíS MODULUS. u. Enter value for

ëyoungs_modulusí : 2300

[Enter].

v. Click POISSONíS RATIO.

w. Enter value for ëpoissons_ratioí :

0.33 [Enter].

x. Click MASS DENSITY.

y. Enter value for ëmass_densityí :

1e-006 [Enter]. z. Click OK.

t

v

x

q

s

p

r

u

w

y

aa. Click ELEMENTS ADD.

bb. Select the elements in the top part of the clip. (they are colored in orange in the model shown)

cc. Click END LIST (#).

These are the elements selected as the top part of the

bb

aa

dd. Click NEW. ee. Click NAME.

ff. Enter material name:

Key [Enter].

gg. Click ISOTROPIC.

hh. Click YOUNGíS MODULUS. ii. Enter value for

ëyoungs_modulusí :

2300 [Enter].

jj. Click POISSONíS RATIO. kk. Enter value for

ëpoissons_ratioí:

0.33 [Enter].

ll. Click MASS DENSITY.

mm. Enter value for ëmass_density:

1e-006 [Enter]. nn. Click OK.

hh

jj

ll

ee

gg

dd

ii

kk

mm

ff

pp

oo. Click ELEMENTS ADD. pp. Select all elements in the key

shaped part. (they are colored in red in the model shown)

qq. Click END LIST (#). rr. Click MAIN.

These are the elements

oo

qq

rr

Create the element property for the clip bottom half.

a. Open GEOMETRIC

PROPERTIES Menu.

b. Click NAME.

c. Enter geometry property name:

all [Enter].

d. Select MECHANICAL ELEMENTS PLANAR. e. Select PLANE STRESS. f. Click THICKNESS. g. Enter value for ëthickí :

0.1 [Enter].

h. Click OK.

Step 4. Geometric Properties: New / Planar / Plane Stress

a

c

e

d

b

f

i. Click ELEMENTS ADD. j. Select all elements. k. Click END LIST (#).

l. Click ID GEOMETRIES. (this action will show if you have selected the right elements) m. Click MAIN.

j

i

k

l

m

Step 5. Boundary Conditions: New / Mechanical / Fixed Displacement

Set the displacement boundary condition for the upper corner of the clip.

a. Open BOUNDARY

CONDITIONS Menu.

b. Click NAME.

c. Enter boundary condition name : Clip_top [Enter].

d. Click MECHANICAL.

e. Click FIXED DISPLACEMENT. f. Click DISPLACEMENT X. g. Enter value for ëxí :

0 [Enter].

h. Click DISPLACEMENT Y. i. Enter value for ëyí :

0 [Enter]. j. Click OK.

a

c

e

f

g

i

h

b

d

k. Click NODES ADD. l. Select Node 1630. m. Click END LIST (#).

l

The model will look like this after you have created the boundary condition.

m

k

n. Click NEW. o. Click NAME.

p. Enter boundary condition name: Clip_bottom [Enter]. q. Click FIXED

DISPLACEMENT.

r. Click DISPLACEMENT X. s. Enter value for ëxí :

0 [Enter]. t. Click OK.

r

p

s

n

o

q

u. Click NODES ADD. v. Select Node 1631. w. Click END LIST (#).

The model will look like this after you have created the boundary condition.

v

u

x. Click NEW. y. Click NAME.

z. Enter boundary condition name : Key [Enter]. aa. Click FIXED

DISPLACEMENT.

bb. Click DISPLACEMENT X. cc. Enter value for ëxí :

-3.9 [Enter].

dd. Click DISPLACEMENT Y. ee. Enter value for ëyí :

0 [Enter]. ff. Click OK.

x

y

aa

z

cc

ee

dd

bb

gg. Click NODES ADD. hh. Select Node 1629. ii. Click END LIST (#). jj. Click MAIN.

hh

gg

ii

jj

Step 6. Contact: New / Contact Bodies / Deformable

Define the clip as a contact body. a. Open CONTACT Menu. b. Click CONTACT BODIES. c. Click NAME.

d. Enter contact body name :

Clip [Enter]. e. Click DEFORMABLE. f. Click OK.

a

b

c

e

d

g. Click ELEMENTS ADD. h. Select all elements in the

clip part using rectangle

picking as shown. (Be careful not to pick

elements at the tip of the key part.)

i. Click END LIST (#).

h

The model will look like this after you have selected the elements.

g

j. Click NEW. k. Click NAME.

l. Enter contact body name :

Pin [Enter]. m. Click DEFORMABLE. n. Click OK.

l

j

k

m

o. Click ELEMENTS

ADD.

p. Select all elements

in the key part

using rectangle picking as shown. (Be careful not to pick elements at the tip of the clip part.) q. Click END LIST (#). r. Click MAIN.

The model will look like this after you have

p

o

q

r

If you want to make sure that you have chosen the elements for the right places, click ID CONTACT.

Step 7. Boundary Condition: New / Mechanical / Table

Table_1 [Enter].

a

b

c

d

The LIMITS in this table will control the displacement of the pin.

The X table value will be assigned as time and the Y time value will be used as time multiplier for the given displacement of the pin.

f. Click MIN.

g. Enter minimum value for V1:

0 [Enter].

h. Click MAX.

i. Enter maximum value for V1 :

2 [Enter].

j. Click YMIN.

k. Enter minimum value for F :

0 [Enter].

l. Click YMAX.

m. Enter maximum value for F :

1 [Enter].

n. Click STEPS.

o. Enter number of steps for V1 :

10 [Enter]. p. Click STEPS.

g

i

k

m

o

q

You can simplify this procedure by clicking on the first label, XMIN, entering the corresponding value, and then keep entering the

subsequent values, one at a time

s

f

h

j

l

n

p

r

t. Enter independent variable V1 value:

1 [Enter].

Enter function value F: 1 [Enter]. u. Enter independent variable V1 value:

2 [Enter].

Enter function value F: 0 [Enter].

This table represents that at 0 sec, the pin will be located at the original place. From 0 to 1 second the pin will move into the Clip for the displacement of ñ 3.9. From 1 to 2 second, the pin will come out from the pin and the final place will be the original place.

t

v. Click TABLE TYPE. w. Click time. x. Click RETURN.

w

x

v

y. Select Key as the NAME. z. Click FIXED

DISPLACEMENT.

aa. Click X DISPLACE

TABLE. bb. Select Table_1. cc. Click OK. dd. Click MAIN.

y

z

bb

aa

cc

Step 8. Load Cases: New / Mechanical / Static

Setup the 2-steps Nonlinear Static Analysis.

a. Open LOADCASES Menu. b. Click NAME.

c. Enter loadcase name :

insert [Enter]. d. Click MECHANICAL. e. Click STATIC.

a

c

b

d

e

.

f. Click MULTI - CRITERIA. g. Click PARAMETERS. h. Click INITIAL FRACTION

OF LOADCASE TIME.

i. Enter loadcase parameter value : 0.02 [Enter].

j. Click MINIMUN FRACTION

OF LOADCASE TIME.

k. Enter loadcase parameter value : 1e-4 [Enter]. l. Click MAXIMUM

FRACTION OF LOADCASE TIME.

m. Enter loadcase parameter value : 0.02 [Enter].

n. Click MAXIMUM # STEPS. o. Enter loadcase parameter

value : 88 [Enter].

g

f

h

j

l

n

i

k

m

o

p. Click SET.

q. Enter loadcase parameter value : 10 [Enter].

r. Click TIME STEP SCALE

FACTOR.

s. Enter loadcase parameter value : 1.5 [Enter].

t. Click OK.

u. Click CONVERGENCE

TESTING.

v. Check AUTO SWITCH. w. Click RELATIVE FORCE

TOLERANCE.

x. Enter loadcase parameter value : 0.15 [Enter]. y. Click OK.

u

q

s

x

v

n

p

r

t

.

z. Click SOLUTION

CONTROL.

aa. Click MAX #

RECYCLES. bb. Enter loadcase parameter value : 25 [Enter]. cc. Select NON-POSITIVE DEFINITE dd. Click OK.

z

bb

aa

cc

ee

hh

.

ee. Click CONTACT.

ff. Check that both Clip and

Pin are highlighted.

gg. Click OK. hh. Click OK.

.

ii. Click COPY. jj. Click NAME.

kk. Enter loadcase name :

extract [Enter]. ll. Click MAIN.

ll

ii

jj

kk

The first loadcase, insert, runs from time 0 to time 1.

The second loadcase, extract, is copied from the first one but will run from time 1 to time 2.

The time table Table_1 controls the total displacement, which goes from 0 to ñ3.9 (total insertion) in the first loadcase and then from ñ3.9 to 0 (back to the original extracted position in the second loadcase.

Step 9. Jobs: New / Mechanical

Select Load Cases.

a. Open JOBS Menu. b. Click MECHANICAL.

a

f

j

c. Select insert and extract. d. Click PLANE STRESS. e. Click CONTACT CONTROL. f. Click ADVANCED CONTACT

CONTROL.

g. Click DISTANCE

TOLERANCE BIAS.

h. Enter job parameter value :

0.99 [Enter].

i. Click OK. j. Click OK.

k. Click ANALYSIS OPTIONS.

c

d

e

k

g

i

h

l. Uncheck LARGE

DISPLACEMENT.

m. Cycle through selection and select LARGE STRAIN

TOTAL LAGRANGE.

n. Cycle through selection and select LARGE STRAIN

ADDITIVE. o. Click OK.

l

m

n

o

p. Click JOB RESULTS.

p

insert extract

q. Select Stress.

r. Select Total Strain. (scroll down to select)

s. Select Equivalent Von Mises

r

s

q

Run results.

a. Open JOBS Menu. b. Click ELEMENT TYPES. c. Click MECHANICAL. d. Click PLANE STRESS.

Step 10. Jobs: New / Mechanical / Run

b

a

d

c

e. Select 3. f. Click OK.

g. Select ALL EXIST. h. Click MAIN.

i. Open JOBS Menu. j. Click RUN.

k. Click SAVE MODEL l. Click SUBMIT (1)

e

f

g

i

j

h

k

m. Click STATUS FILE.

The details of status file is copied on the next three pages of the workshop.

Those details may change somewhat from version to version of MSC.Marc because of improvements made to the

Wait until the MSC.Marc finishes running. When the STATUS says ìcompleteî, then click Status file.

Beginning of insertion (Step 1)

Some nodes separate (lose contact)

Largest allowed load increment: 0.02

Largest number of cycles (iterations) during insertion: 79

Most difficult moment (snap in) during insertion Largest number of separations: 11 End of insertion Beginning of extraction (Step 2) Most difficult

moment (snap out) during extraction

Normal termination code Total number of load increments End of extraction n. Click OK. o. Click MAIN.

Step 11. Results: Open Default / Def Only / Monitor

Monitor results.

a. Open RESULTS Menu. b. Click OPEN DEFAULT. c. Click DEF ONLY.

d. Click CONTOUR BANDS e. Click SCALAR

f. Select Equivalent Von Mises

Stress

g. Click OK

h. Click MONITOR.

a

This animates the

deformation as the insertion

f

g

b

c

d

e

h

Step 12. Results: History Plot / Set Nodes / Time

Create the History Plot for the reaction force.

a. Click HISTORY PLOT. b. Select SET NODES. c. Select the 3 independent

(control) Nodes (1629-1631) d. Click END LIST (#).

a

b

c

e. Click COLLECT GLOBAL

DATA.

f. Click NODES/VARIABLES. g. Select ADD VARIABLE. h. Select GLOBAL VARIABLES

Time.

i. Select VARIABLES AT NODES

Reaction Force X.

j. Click ADD NODE.

k. Select 1629 from the NODES. l. Click Fit.

e

f

g

h

i

j

k

l

When you are done working with this model

a.

Click on

b.

then click on

WORKSHOP 4

NECKING OF A TEST SPECIMEN

Symmetr

y Plan

e

■

Model Description

◆

In this lesson, you will stretch an 8 inch long planar steel bar by

1.65 inches (i.e. more than 20% of its length). This elastic-plastic

problem will demonstrate the importance of the concept of true

stress (or Cauchy stress) in non-linear analysis. This test specimen

will be modeled using a quarter symmetry model.

■

Objective

◆

Large Deflections/Strains analysis

◆

Elastic-Plastic material model using isotropic hardening

■

Required

■

Suggested Exercise Steps

1.

Create a 4x1 inch surface in the XY plane Model the

contact surfaces with LBC contact

2.

Mesh the model with 16x4 mesh of QUAD/4 elements.

3.

Fix the vertical and horizontal lines of symmetry of the bar