Example: Minimizing Compliance

The task for this example is to minimize compliance (maximize stiffness) of a structure with respect to the 2nd load case in the finite element input deck.

This task shows you how to:

Define compliance in Tosca ANSA® environment

Tosca ANSA® environment only admits design responses to be defined below either OBJ_FUNC_ITEM_1 item or CONSTRAINTS item.

  1. In OBJ_FUNC_ITEM_1 menu, choose Edit.

  2. In OBJ_FUNC_ITEM dialog, choose TARGET = MIN, because the compliance is to be minimized in order to maximize the stiffness.

  3. As shown in the figure above, apply OBJ_FUNC_ITEM_1 > New > COMPLIANCE command on .

  4. In the OBJ_FUNC_TERM dialog, press "?" key in LC_SET field.

  5. In LC_SET dialog click MORE and enter the load case number (2 for the second load case) in the second text field of the appeared line.

Define compliance in Tosca Structure.gui

  1. Choose Command > DRESP.

  2. Click Apply Template and choose Sum of Strain Energy as shown in the figure below:

  3. To choose a load case, click Add LC. In the field load case number enter 2.

  4. Choose Command > OBJ_FUNC.

  5. Click Add Dresp and choose the previously defined design response for compliance:

Define compliance in Tosca Extension for ANSYS® Workbench

  1. In order to minimize the compliance, add a design response at first and choose Stress/Strain as Category and Strain Energy as Response Type.

  2. Select the required Load Cases:

  3. When done, add an objective function to the project. Select Minimize sum as Target and select the previously defined design response in a new tab:

SIMULIA Tosca Structure Parameter File

  • The resulting command in the parameter file look like follows: 

    DRESP
 ID_NAME = compliance
 TYPE = STRAIN_ENERGY
 DEF_TYPE = SYSTEM
 LC_SET = STATIC,2,
 EL_GROUP = ALL_ELEMENTS
 GROUP_OPER = SUM

END_


    OBJ_FUNC
 ID_NAME        = MY_OBJ_FUNC
 DRESP          = compliance
 TARGET         = MIN
END_