OS-E: 2040 Contact Pressure Response

This example highlights the OptiStruct capability to use nonlinear responses in optimization from version 2018 onwards.

The contact pressure and contact force can be used as response in DRESP1 card in optimization formulation. Contact pressure is output under contact traction/normal and contact force is output under contact force/normal, contact force/tangent. Response from the main surface is used in optimization formulation.

Model Files

Before you begin, copy the file(s) used in this example to your working directory.

Model Description

Model consists of two solids with thickness of 20 mm each. Node to surface contact is established between the solids. For the nonlinear static analysis run, a force of 900N distributed centrally over the top solid surface (9*100) is applied. Optimization with objective of minimizing the mass with the contact pressure set at upper bound of 0.335 as the constraint is set up.

Material properties are:
Young's modulus
210 x 103 MPa
Poisson's ratio
7.9 x 10-9 ton/mm3


Figure 1. Contact Force Distribution at Iteration 0 and Load Factor 1.00

Figure 2. Contact Force Distribution at Iteration 5

The converged optimized model, the weight has reduced weight from 2.37635 E-3 to 2.37585 E-3 tons and the contact pressure is reduced from 0.3444 MPa to 0.3351 MPa.