Hao Lyu1, Hongchen Qu1, Zaiyou Yang1, Li Ma1, Bing Lu1, and Michael Pecht2
1School of Mechanical Engineering and Automation, Northeastern University, Shenyang 110003, China
2Center for Advanced Life Cycle Engineering, University of Maryland, College Park, MD 20742, USA
For more information about this article and related research, please contact Prof. Michael Pecht.
The dependent competing failure process model has received increasing research attention in recent years due to its essential role in describing system reliability. For the δ shock model, as a main type of shock in dependent competing failure process, the system fails if the interval of time between two sequential shocks is less than a threshold δ. As the operation of systems, the aging effect will gradually increase. Thus, systems affected by shocks need more time to recover from damages. In the time-varying δ shock model, if damage shocks occur, the degradation rate and δ value will change multiple times simultaneously. Three failure processes consisting of a soft process induced by a degradation process and two sudden failure processes due to random shocks. Sudden failure processes include fatal shocks and damaged shocks. Damaged shocks affect systems in three different ways: (1) impacting systems by causing the degradation increment, (2) increasing the degradation rate of systems, and (3) impairing systems’ performance by increasing the δ value. A real-world example of a microelectromechanical system is presented to show the applicability of the reliability model. Sensitivity analysis is evaluated to demonstrate how parameters affect reliability.
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