About the Mechanism Example

The present example shows that the topology optimization by SIMULIA Tosca Structure is also capable of performing a mechanism design. The object function is now different, here opposite, from the classic compliance formulation. The objective is now to maximize the displacement of a node for a given actuator force.

This page discusses:

About the Model

The symmetry of the structure and optimization problem is used in the input model. The input model as well as the optimization results shows one half of the model (the upper rectangle) only. However the complete model (the rectangle plus its reflection around the lower side) are used in the finite element analysis and the optimization. In the optimized model, the middle point of the right side (the point where the spring is attached) is displaced toward the inside of the model (that is, in the negative x direction) Therefore the absolute value of the displacement is maximal if the displacement itself (that is negative) is minimal. Thus, the objective function is the minimization of the displacement of the node.

The upper left corner and the lower right corner of the half of the model (corresponding to both the left corners and the middle of the right side of the entire model) are the frozen areas. The elements at these points constitute the group support:



Procedure Summary

Model:mechanism.ext
Design Area:All elements
Design Variable Constraint: The support group is marked as frozen
Objective:Minimize the displacement in the x direction of the node with ID = 2
Constraint:Relative volume is less than 25% (inequality constraint)
Iterations:Not more than 150 iterations
Settings:FILTER_RADIUS = 0.04