The bathtub curve: an alternative explanation

A viable explanation to the reliability bathtub curve is presented wherein failure rate is governed by a physical process of component strength decay over time due to a distributed applied stress. In this proposed alternate approach to studying reliability, interdisciplinary boundaries are crossed as links between the fields of reliability engineering, quality control and fracture mechanics are achieved. Further, this physical explanation of hazard rate rejects the traditional and strictly statistical viewpoint that the bathtub curve can be compartmentalized into early, constant and wear-out failures, and instead supports the more recent claim that most failures are due to wear-out. The paper intends to break from strictly statistical reliability approaches and to provide a foundation for the development and application of reliability techniques based on physical science theories