A Model for Time Varying and Interfering Stress-Strength Probability Density Distributions with Consideration for Failure Incidence and Property Degradation

The Reliability prediction approaches which are commonly used to estimate the Reliability of complex electronic devices are shown not to apply to the structural elements of the highly stressed parts of such mechanical devices as turbojet engines. The paper introduces the fundamental relationships of computing the probability of failure from interfering and compatible stress-strength probability functions as the most promising approach to the Reliability analysis of structural elements. The changes of the probability density functions with time as a result of failure incidence probability and strength degradation are analyzed and described. The effect of these changes on the probability of failure in the sense of a force of mortality function are introduced and a digital computer approach to the solution of the analytical complexities is described. Preliminary results from this computerized approach to structural Reliability analysis are given.