# OS-E: 0920 Ten Bar Truss

Demonstrates how size (parameter) optimization can be used.

## Model Files

Refer to Access the Model Files to download the required model file(s).

The model file used in this example includes:

tenbar.fem

## Model Description

For the ten bar truss structure, a cross-sectional area distribution is sought that minimizes the structural mass and allows limited stress values in the elements. The stress limit is 25000. The y displacements are limited to 2.

The cross-sectional area for each element is varied. Therefore, 10 variables are defined in the analysis deck. The initial cross-sectional area of all the elements is 20, with a lower bound of 0.2 and an upper bound of 200.

The optimization problem, objective and constraint functions, is defined in the same manner as for the other types of structural optimization. OptiStruct then goes through an iteration process to solve the optimization problem. OptiStruct converged after thirteen iterations.

## Results

Bar1 | Bar2 | Bar3 | Bar4 | Bar5 | Bar6 | Bar7 | Bar8 | Bar9 | Bar10 | Volume | |
---|---|---|---|---|---|---|---|---|---|---|---|

Initial | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 83929 |

Final | 30.4 | 38.4 | 24.5 | 15.4 | 0.2 | 0.2 | 8.8 | 21.5 | 20.1 | 0.4 | 51448 |