Extension and evaluation of fatigue model for product shock fragility usedin package design

Earlier work that incorporated fatigue into the description of the shock fr agility of products is expanded to include more sophisticated models of fai lure. The robust nature of the original model, which treats fragile interio r components as single-degree-of-freedom spring/mass systems deforming in a n elastic/perfectly plastic manner under dynamic loading, is demonstrated i n three ways. The first compares the model predictions with experimental re sults, which include the generic findings referenced in an ASTM standard. T he second and third are based on comparisons with an exact analysis of elas tic/linear plastic springs and an approximate analysis of the most general model possible.