Hertz Contact - MSC SimCompanion

aboundingdriprockΠολεοδομικά Έργα

29 Νοε 2013 (πριν από 3 χρόνια και 8 μήνες)

128 εμφανίσεις

Hertz Contact

Estimated Time for Completion: 30 minutes

Experience Level: Lower

MSC.Marc 2005r2

MSC.Patran 2005r2

2

Topics Covered




Creating deformable contact boundary conditions of two
bodies


Controlling solutions for nonlinear geometric effects


Reviewing the results and comparing to a theoretical value


Using local adaptive meshing

3


In this example problem, a steel cylinder with a radius of 5”
is pressed against a 2” deep aluminum base. The problem
is linear except the contact condition at the base which is
modeled using the contact pair approach.



We will use Patran to complete the problem description from
a given 2D meshed model and analyze it by using Marc.

Problem Description

4

Summary of Model

5” radius

10,000 psi pressure

16”

2”

Constrain 2 nodes
along the vertical
center line <0,,>

Constrain all bottom nodes <,0,>

Constrain any node
along the vertical center
line <0,,>

Steel

E = 30E6

v = 0.30

Aluminum

E = 10E6

v = 0.33

5

Goal


In this example, we will determine the maximum compressive stresses
in a cylinder and a flat plate being compressed against each other.


The results from Marc will be compared to a theoretical value.


We will also demonstrate how the results can be improved through the
use of adaptive meshing.


6

Expected Results

Y
-
Component stresses

Results WITHOUT the use of adaptive meshing

Maximum compressive
stress is 2.12E5 psi.

7

Expected Results

Y
-
Component stresses

Results WITH the use of adaptive meshing

Y
-
Component stresses

Maximum compressive
stress is 2.38E5 psi.

8

Create Database

Create Database

a.
Click
File

menu / Select
New

b.
In
File Name
, enter
hertz.db

c.
Click
OK

d.
Select
Analysis Code

to be
MSC. Marc

e.
Click
OK

a

b

c

d

e

9

Import Model

a.
Click
File

menu / Select
Import

b.
Select Source to be
MSC. Patran DB

c.
Locate and select file

hertz_model.db

d.
Click
Apply

a

b

c

d

10

Create Fixed Displacements

a

a.
Click
Loads/BCs

icon

b.
Select
Action

to be
Create

c.
Select
Object

to be
Displacement

d.
Select
Type
to be

Nodal

e.
In
New Set Name
, enter
fixed_base_x

f.
Click
Input Data

g.
In
Translations
, enter
<0, ,>

h.
Click
OK

i.
Click
Select Application Region

j.
Select
Geometry Filter

to be
FEM

k.
In
Select Nodes
, select

any node along vertical line
of the base
from screen or enter
Node 1167

l.
Click
Add

m.
Click
OK

n.
Click
Apply

Repeat (e)


(m) for the following new sets of BCs

New Set Name

Translations

Application Region

fixed_base_y

< ,0, >

All nodes at bottom of base

(Node 1145:1189)

fixed_cylinder_x

<0, ,>

Any two nodes along vertical center line of cylinder

(Node 326 327)

b

c

d

e

f

g

h

i

j

k

l

m

n

11

a.
Select
Object

to be
Contact

b.
In
New Set Name
, enter
base_contact

c.
Select
Target Element Type

to be
2D

d.
Click
Select Application Region

e.
Select
Geometry Filter

to be
Geometry

f.
In
Select Surfaces
, select

base
on screen or enter
Surface 3

g.
Click
Add

h.
Click
OK

i.
Click
Apply


Create Deformable Contacts

Repeat (b)


(i) for the following new set of BCs

New Set Name

Application Region

cylinder_contact

Two surfaces on cylinder (Surface 1 2)

a

b

c

d

e

f

g

h

i

12

Create Pressure

a.
Select
Object

to be
Pressure

b.
In
New Set Name
, enter
pressure

c.
Select

Target Element Type

to be
2D

d.
Click
Input Data

e.
In
Edge Pressure
, enter
10000

f.
Click
OK

g.
Click
Select Application Region

h.
In
Select Surfaces or Edges
, select

edges on top of cylinder

and click
Add

to add the selected edge to
Application Region

one by one or enter
Surface 1.4 2.2

i.
Click
OK

j.
Click
Apply

a

b

c

d

e

f

g

h

i

j

13

Define Material

a

a.
Click
Materials

icon

b.
In
Material Name
,

enter
steel

c.
Click
Input Properties

d.
In
Elastic Modulus
, enter
30e6

e.
In
Poisson Ratio
, enter
0.3

f.
Click
OK

g.
Click
Apply

Repeat (b)


(g) for the following new material

Material
Name

Elastic Modulus

Poisson Ratio

aluminum

10e6

0.33

b

c

d

e

f

g

14

Define Element Properties

a

a.
Click
Properties

icon

b.
Select
Type

to be
2D Solid

c.
In
Property Set Name
, enter
cylinder_prop

d.
Click
Input Properties

e.
Click
Mat Prop Name

icon and select
steel

f.
In
Thickness
, enter
1

g.
Click
OK

h.
In
Select Members
, select
surfaces of
cylinder
on screen or enter
Surface 1 2

i.
Click
Add

j.
Click
Apply

Repeat (c)


(j) for the following new property

Property
Set Name

Material

Thickness

Members

base_prop

aluminum

1

Surface of base

(Surface 3)

b

c

d

e

f

g

h

i

j

15

Modify Solution Control and Run Analysis

a

a.
Click
Analysis

icon

b.
Click
Load Step Creation

c.
Click
Solution Parameters

d.
Select
Nonlinear Geometric
Effects

to be
None

e.
Click
OK

f.
Click
Apply
(answer
Yes

to
modify the
Default Static Step
)

g.
Click
Apply


** Wait until analysis is completed **


b

c

d

e

f

g

16

Read Results File

a.
Select
Action

to be
Read Results

b.
Click
Select Results File

c.
Locate file
hertz.t16

d.
Click

OK

e.
Click
Apply


a

b

c

d

e

17

Plot Results

Maximum
compressive
stress is 2.12E5

a

a.
Click
Results

icon

b.
In
Select Result Cases
, select the
last increment

c.
In
Select Fringe Result
, select
Stress, Global System

d.
Select
Quantity

to be
Y Component

e.
In
Select Deformation Result
, select
Displacement, Translation

f.
Click
Apply


b

c

d

e

f

18

Theoretical Comparison

19

Theoretical Comparison

Max

c

% Difference

Theoretical

FEA

Marc

2.309E5

Maximum compressive stress

20

Turn On Adaptive Meshing and Run Analysis

a

a.
Click
Analysis

icon

b.
In
Job Name
, enter
hertz_amesh

c.
Click
Job Parameters

d.
Click
Adaptive Meshing

e.
Select
Adaptivity

Type to be
Local

f.
In
Zone Name
, enter
contact_zone

g.
In
Select a Group
, select
all

h.
Click
Apply

i.
Click
OK

j.
Click
OK

k.
Click
Apply


** Wait until analysis is completed **

b

c

d

e

f

g

h

i

j

k

21

Read Results File

a.
Select
Action

to be
Read Results

b.
Click
Select Results File

c.
Locate file
hertz_amesh.t16

d.
Click

OK

e.
Click
Apply


a

b

c

d

e

22

Plot Results

Maximum compressive stress is 2.38E5

a

a.
Click
Results

icon

b.
In
Select Result Cases
, select the
last increment

c.
In
Select Fringe Result
, select
Stress, Global System

d.
Select
Quantity

to be
Y Component

e.
In
Select Deformation Result
, select
Displacement, Translation

f.
Click
Apply


b

c

d

e

f

23

Investigate Modified Meshes

Meshes have been refined
automatically where the
contact occurred, giving
more accurate results.

24

Theoretical Comparison


Investigate the improvement in the results when
using adaptive meshing

Max

c

% Difference

Theoretical

FEA

Marc

2.309E5

Marc with
adaptive mesh

2.309E5

Maximum compressive stress

Use of adaptive meshing, which refines meshes in the contact zone, can
improve the accuracy of the results without having to refine meshes of the
entire model.