A parametric analysis solves for the response as a function of a parameter. You can freely define the parameter name and what it affects; it can be a material property, a load parameter, or some other expression.
The purpose of this example is to find the response to static loading of the bracket as a function of the direction of the load parameterized by the angle α.
Apply the load on the face shown in Figure 2. To control the direction of the load, introduce a parameter in the load expressions:
(6)
Solved with COMSOL Multiphysics 4.2a
Results and Discussion
The following plot shows the x-, y-, and z-displacements as functions of the direction of the load, α, at a point on the surface where the load is applied:
Figure 13: Displacement amplitudes versus load direction.
Notes About the COMSOL Implementation
When you perform a parametric study, you will select the underlying study type (here:
Stationary) first. The you add a Parametric feature, and define the parameter values.
Modeling Instructions
M O D E L W I Z A R D
1 In the Model Builder window, right-click the root node and choose Add Study. 2 Go to the Model Wizard window.
3 Find the Studies subsection. In the tree, select Preset Studies>Stationary. 4 Click Finish.
S T U D Y 8
1 In the Model Builder window, right-click Study 8 and choose Rename.
Solved with COMSOL Multiphysics 4.2a
44 | V A R I O U S A N A L Y S E S O F A N E L B O W B R A C K E T © 2 0 1 1 C O M S O L
2 Go to the Rename Study dialog box and type Study 8 (Parametric Static) in the New name edit field.
3 Click OK.
4 Right-click Study 8 and choose Parametric Sweep.
It is necessary to define the parameters to be used. The values given here do not influence the parametric solver, but can be used for tests outside it.
G L O B A L D E F I N I T I O N S
Parameters
1 In the Model Builder window, right-click Global Definitions and choose Parameters. 2 Go to the Settings window for Parameters.
3 Locate the Parameters section. In the Parameters table, enter the following settings:
Add a load with a parameter dependency.
S O L I D M E C H A N I C S
Modal Frequency Load
In the Model Builder window, right-click Modal Frequency Load and choose Disable. Boundary Load 5
1 Right-click Solid Mechanics and choose Boundary Load.
2 In the Model Builder window, right-click Boundary Load 5 and choose Rename. 3 Go to the Rename Boundary Load dialog box and type Parametric Load in the New
name edit field.
4 Click OK.
5 Select Boundary 29 only.
6 Go to the Settings window for Boundary Load.
7 Locate the Force section. Specify the FA vector as
NAME EXPRESSION DESCRIPTION
alpha -45 Solver parameter
3[MPa]*cos(alpha*pi/180) X
0 Y
3[MPa]*sin(alpha*pi/180) Z
Solved with COMSOL Multiphysics 4.2a
S T U D Y 8 ( P A R A M E T R I C S T A T I C )
Parametric Sweep
1 In the Model Builder window, click Study 8 (Parametric Static)>Parametric Sweep. 2 Go to the Settings window for Parametric Sweep.
3 Locate the Study Settings section. Under Parameter names, click Add. 4 Go to the Add dialog box.
5 In the Parameter names list, select alpha (Solver parameter). 6 Click the OK button.
7 Go to the Settings window for Parametric Sweep.
8 Locate the Study Settings section. In the Parameter values edit field, type range(-45,5,45).
Solver 8
1 In the Model Builder window, right-click Study 8 (Parametric Static) and choose Compute.
2 Expand the Study 8 (Parametric Static)>Solver Configurations node.
3 Right-click Study 8 (Parametric Static)>Solver Configurations>Solver 8 and choose Rename.
4 Go to the Rename Solver dialog box and type Parametric Static Sequence in the New name edit field.
5 Click OK. R E S U L T S
Data Sets
1 In the Model Builder window, right-click Results>Data Sets>Solution 8 and choose Rename.
2 Go to the Rename Solution dialog box and type Parametric Static Solution in the New name edit field.
3 Click OK. Stress (solid)
In the Model Builder window, right-click Results>Stress (solid) and choose Delete. 1D Plot Group 12
1 Right-click Results and choose 1D Plot Group.
Solved with COMSOL Multiphysics 4.2a
46 | V A R I O U S A N A L Y S E S O F A N E L B O W B R A C K E T © 2 0 1 1 C O M S O L
2 Go to the Settings window for 1D Plot Group.
3 Locate the Data section. From the Data set list, choose Parametric Static Solution. 4 Click to expand the Title section.
5 From the Title type list, choose None.
6 Locate the Plot Settings section. Select the x-axis label check box.
7 In the associated edit field, type Force direction (degrees). 8 Select the y-axis label check box.
9 In the associated edit field, type Displacement (mm). 10Right-click Results>1D Plot Group 12 and choose Point Graph. 11Select Point 30 only.
12Go to the Settings window for Point Graph.
13Locate the y-Axis Data section. In the Expression edit field, type u. 14Locate the Legends section. Select the Show legends check box.
15From the Legends list, choose Manual. 16In the table, enter the following settings:
17Right-click Point Graph 1 and choose Duplicate. 18Go to the Settings window for Point Graph.
19Locate the y-Axis Data section. In the Expression edit field, type v.
20Locate the Coloring and Style section. Find the Line style subsection. From the Color list, choose Green.
21Locate the Legends section. In the table, enter the following settings:
22Right-click Point Graph 2 and choose Duplicate. 23Go to the Settings window for Point Graph.
24Locate the y-Axis Data section. In the Expression edit field, type w.
25Locate the Coloring and Style section. Find the Line style subsection. From the Color list, choose Red.
LEGENDS X
LEGENDS Y
Solved with COMSOL Multiphysics 4.2a
26Locate the Legends section. In the table, enter the following settings:
27Click the Plot button.
28In the Model Builder window, right-click 1D Plot Group 12 and choose Rename. 29Go to the Rename 1D Plot Group dialog box and type Parametric Response
Graphs in the New name edit field.
30Click OK.