Reliability modeling for competing failure processes with shifting failure thresholds under severe product working conditions

Abstract Considering the complex product working circumstances under severe conditions, this paper first specifies the shock processes that a product experiences. The multi-stage description of competing failure processes is accomplished by considering various factors affecting the performance degradation process as well as by introducing the soft failure threshold in order to effectively illustrate the overall failure process of the product. The concepts of shock damage and intensive shocks are introduced to modify the traditional shock models. The difficult problem of adding the arrival time of shocks to the reliability model is solved by using the multivariable integrals. The competing failure model based on the extreme shock damage and the delta-shock competing failure model considering the intensive shocks are presented. Finally, the proposed models are applied to evaluate the reliability of a certain micro engine. The influence of the parameters on the model reliability is analyzed, and the proposed models are compared with an existing reliability model. The results demonstrate that the proposed models can effectively describe the competing failure process and show certain feasibility and theoretical reference values.