Author: Sebastien Lachance-Barrett, Cornell University

Problem Specification

1. Pre-Analysis & Start-Up

2. Initial Solution

3. Input & Output Parameters

4. Design of Experiments

5. Response Surface

6. Optimization

7. Verification & Validation

Exercises

Comments

# Design of Experiments

This step samples specific points in the design space. It uses statistical techniques to minimize the number of sampling points since a separate FEA calculation (and associated stiffness matrix inversion) is required for each sampling point. This is the most time-consuming step in the optimization process.

### Response Surface Optimization

First, Goal Driven Optimization needs to be placed in the Project Schematic. In the left-hand menu called "toolbox" expand ** Design Exploration. **Next, drag

**and drop it right underneath the**

*Response Surface Optimization***. Your project schematic window, should look comparable to the one below. Note that all the systems are connected.**

*Parameter Set*

Next, double-click ** Design of Experiments.** Again, we can see our input and output parameters but this time under the Design of Experiments step.

Highlight ** P1-DS_R** and change the Lower Bound to 1 inch and the Upper Bound to 2.5 inches.

Now, that the radius of the hole is properly constrained click on ** **. ANSYS just picked what it thinks are the best sampling points according to an algorithm. Note that these sampling points are not necessarily linearly spaced. To get a numerical solution for each of these radii, click

**.**

*Update*If you get the following error, click ** Yes**.

Twiddle your thumbs a bit while ANSYS performs some time-consuming matrix inversions.

After the update has completed, click on ** Return To Project**. You may want to save again at this point.