A dynamic imperfect inspection-based maintenance optimization considering dependent competing failure

• Propose a maintenance optimization model based on dynamic imperfect inspection. • Develop a dual inspection model based on time-based and shock-based inspection. • Propose a two-phase degradation process with dependent competing failure. • Develop the cost rate model for finite time using the renewal reward theory. • Conduct a case study of a marine hydraulic pump to verify the proposed model. In order to ensure highly reliable and safe operation of electromechanical component, it is essential to develop an efficient and cost-effective maintenance plan. However, the development of a generic and cost-effective maintenance plan is challenging due to dynamic imperfect inspection and multiple failure modes. Therefore, this paper proposes a maintenance optimization model under dual inspection strategy considering dependent competing failure and dynamic imperfect inspection. Specifically, a dependent competing failure model is introduced to describe the competitiveness and dependence of internal degradation and external shocks. The degradation of the component is portrayed with a two-phase successive degradation based on the delay time model. Shock-based inspection is then proposed, which is developed into a dual inspection model with time-based inspection. In addition, a dynamic probability model of imperfect inspection is developed based on the limitation of the inspection technique, human error, and working environment. Furthermore, the cost rate model for finite time is developed using the renewal reward theory to determine the optimal inspection interval. Finally, the validity of the model is verified through a real case on the marine hydraulic pump .