Concept of durability index in product assurance planning

Interrelationships among customer expectations, engineering requirements, and current definitions of durability in the automobile industry are examined. A durability index (DI) is developed to complement inefficient existing definitions. Inherent deficiencies of current reliability development programs (CRDPs) are discussed, and a new methodology of robust reliability/durability development methodology (RR/DDM) is proposed which blends G. Taguchi´s (1988) robust design methodology into the CRDP. Under this philosophy, reliability (life) testing serves only as a final validation tool, not a debugging device for design weaknesses