Reliability analysis on competitive failure processes under fuzzy degradation data

Reliability is the ability of a system to perform its required functions under stated conditions for a specified period of time. Reliability analysis is an important tool to evaluate the performance of a system and make maintenance decision. In engineering practices, there are usually several processes to cause a system to failure. Generally, the failure processes can be categorized into degradation process and shock process. This research investigates the system reliability analysis when both degradation process and shock process are involved. Furthermore, the effect due to shock process on the degradation process is considered and degradation analysis is conducted under fuzzy degradation data. After that, a system reliability model on competitive failure processes under fuzzy degradation data is constructed. Since several states are formed when the effect due to shock process on degradation process is accounted for, multi-state system reliability theory is employed to evaluate the proposed model. This method could be used to assess reliability of many devices precisely in the real world, such as diesel engines. A practical engineering example is provided to illustrate the proposed model and method.