Vagaries of elastomer service life predictions

Abstract

Generally, the useful life of a rubber component is governed by its susceptibility to failure by either mechanical or chemical deterioration. There are well established laboratory tests to address the failure properties of elastomers – fracture mechanics analyses for mechanical durability and accelerated aging tests for chemical degradation. However, laboratory predictions are reliable only to the extent that the relevant failure mechanisms are identified and all contributing factors are accounted for. This paper describes two case studies, one concerning fatigue failure of an elastomeric mechanical capacitor and the other thermal oxidation of a radiant heating hose. Ironically only the latter case, in which redundant laboratory testing provided accurate lifetime predictions, involved product failure with consequent extraordinary financial losses.