PATRAN Beginner's Guide

¦
¡ ¥
¢
¢
¢
¢
¢
¢
¢
¢
¢
¢
6 DEFINE ELEMENT PROPERTIES 5.3 Load Application
6 DEFINE ELEMENT PROPERTIES 6.1 Define Material Properties
5.3 Load Application
Along the top, the side on the right hand is to be subjected to a vertical triangular distributed load
which varies from 100 to 0.
The load distribution function has already been specified in the previous section.
To specify this, set the ’Action’ to ’Create’ and change the ‘Object’ to ‘Pressure’. Enter dstld (short
for distributed loading) in the box marked ‘New Set Name’.
This is the label by which the load will be identified (Figure 20).
Click on the ‘Input Data...’ button and click on the box marked ‘Edge pressure (2-D Solids)’ and
click on the label triang in the field box marked ‘Field’. The label f:triang should be displayed in
that box.
Click on the OK button.
Then click on ‘Select Applications Region...’. Click on the box marked ‘Select Geometry Entities’.
Choose the ‘Curve’ icon from the ‘Select Menu’ (it is the 1st icon). Then click on curve marked C
in Figure 20.
The label ‘Surface 3.2’ should appear in the box marked ‘Select Geometry Entities’.
Click on the ‘Add’ button. The label ‘Surface 3.2’ should appear in the box marked ‘Application
Region’. Then click on the OK button to close that form.
In the original form click on the Apply button.
This completes the specification of the load. The load vector should be displayed in Red. The
values 100 and 0 should be displayed at either ends. If this does not happen then you must have made
a mistake. Change the ‘Action’ from ‘Create’ to ‘Modify’. Check that the ‘Input Data’ and ‘Application
Region’ are correct for the above load application. You can also change the ‘Action’ to ‘Show Tabular’
to check the input data. Then proceed with the exercise.
The next step is to input the material properties.
6 Define Element Properties
First a material called steel is created and the properties defined (E, ). Then these properties are
assigned to the bracket and the thickness is also specified. These are defined in two different forms.
Load/Boundary Conditions
Action:
Object:
Type:
Create
Pressure
New set Name
dstld
Target Element Type :
Input Data ...
Element Uniform
Edge Pressure (2D−Solids)
f: triang
Spatial Fields
triang
OK
Geometry
FEM
2D
Select Application Region...
Select Surfaces or Edges
Click in this box and DO NOT press
enter name ’dstld’. the RETURN key.
Change this from 3D to 2D.
Click on this box.
Click in this box and then click on
triang in the ‘Spatial Fileds’ Box below.
This should then display ‘F : triang’.
The Loads and BCs can be associated with either
the geometry or the finite element model.
The default pick is "Geometry".
Click in this box.
C
Key
Select menu
Pick
6.1 Define Material Properties
The bracket is made out of steel. Here it is assumed to be isotropic and linear elastic.
Click on the
Materials for specifying the material properties.
Figure 21 shows the form which is used to input the material properties for the bracket.
Click on ‘Isotropic’ and look at the other constitutive models that can be chosen. Leave it unchanged
for the present.
Enter the Material Name Steel.
Select ‘Input Properties...’. Enter an Elastic Modulus of ‘2.1E5’ (in MPa), Poisson’s ratio of 0.3.
Click on the ‘OK’ in this form and then click on ‘Apply’ in the original form. This completes the
input of material properties.
If you need to check the material properties at a later stage, change the ‘Action’ from ‘Create’ to
‘Show’. To make any changes, change the ‘Action’ to ‘Modify’.
−Apply−
Add
Click on the "Curve" icon to select it. It is the 1st icon in the select menu.
This selection filters screen picking. In this case only the curves or edges
will be selected, although there may be points or surfaces in the area.
Then click on top line in surface 3 (Line C in above). The label ‘Surface 3.2’
should appear in the box marked ‘Select Surfaces or Edges’.
OK
Click on this and the information should
appear the ‘Application Region’.
Figure 20: Load Application
27
28