A Cost-Effective Strength-Stress Reliability Modeling and Optimization in Engineering Design

Abstract Because of manufacturing variability, the strength of a component may vary significantly and unpredictably. When a component is put into use, it is subjected to a stress, which is also unpredictable. If the strength of the component is sufficient to withstand stress, then the component is functional. Otherwise, the component fails immediately. Achieving higher reliability requires higher costs. This paper first shows two reliability optimization models using normally distributed strength and stress: one is to maximize reliability subject to maximally allowable cost associated with reliability, while the other is to minimize the cost subject to a required minimum reliability level. The paper then proceeds by showing how these two conflicting decision criteria are comprised in a joint manner by presenting a proposed cost-reliability compromise model. A numerical example along with sensitivity analysis is presented and compared with previous work.