Several techniques are available to determine whether a part failed due to excessive stress.

Finite element analysis can provide an estimate of resultant stress within the part. The stress may be compared to yield stress values to evaluate the performance requirements of the part.

Strain Gage Analysis

Eastman has a computerized strain gage test machine. The machine can provide measurements of strain on an existing part in its end-use function. The photograph below shows two strain gage rosettes on a snap-fit latch. The gages were used to verify the accuracy of a baseline finite element analysis.

Three Strain Gage Rosettes on a Cantilever Snap-fit Latch