Verification & Validation — Lesson 8

As with any numerical method verification and validation are of great significance. As mentioned earlier, there is no analytical solution for the finite plate with a hole. Thus, the results can not be compared to theory. Thus, in this section other verification and validations will be used. First, the solution will be examined as the mesh is refined to see if it has converged. Additionally, the optimization results will be verified by using different optimization methods and comparing results.

Mesh Refinement

The convergence criteria which was inserted earlier was used to view the effect of mesh refinement with a radius of 1.4853 inches.

Number of Elements Equivalent Von Mises Stress (PSI) Percentage Change
244 32,495
775 32,712 0.6656

As you can see from the data above, over the course of the mesh refinement, the equivalent von Mises stress only changes by less than one percent. Thus, the solution has been verified with respect to mesh refinement. However, notice how the equivalent von Mises stress now lies above our constraint. While our optimization looked promising, we had not taken into account the slight change in results from a finer mesh.

Optimization Methods

The optimization was carried out using each of the four optimization methods offered in Ansys Workbench. Note that the default optimization method in Workench was Screening but now is MOGA.

Optimization Method Radius (In) Volume (In^3) Equivalent Von Mises Stress (PSI)
Screening 1.3278 9.8615 32,484
MOGA 1.3267 9.8618 32,500
NLPQL 1.3291 9.8613 32,503

As you can see from the table above, there is no significant difference between the results from the four methods.