A random shock model with mixed effect, including competing soft and sudden failures, and dependence

TL;DR

This paper models a complex system subject to external fatal shocks, soft and sudden failures, analyzing how dependencies and environmental parameters influence system reliability and lifetime.

Contribution

It introduces a comprehensive shock model incorporating dependence, competing failure modes, and multiple calculation methods for system reliability.

Findings

Conditions for New Better than Used lifetime property.

Impact of shock parameters on system reliability.

Comparison of four reliability calculation methods.

Abstract

A system is considered, which is subject to external and possibly fatal shocks, with dependence between the fatality of a shock and the system age. Apart from these shocks, the system suffers from competing soft and sudden failures, where soft failures refer to the reaching of a given thresh-old for the degradation level, and sudden failures to accidental failures, characterized by a failure rate. A non-fatal shock increases both degradation level and failure rate of a random amount, with possible dependence between the two increments. The system reliability is calculated by four different methods. Conditions under which the system lifetime is New Better than Used are proposed. The in uence of various parameters of the shocks environment on the system lifetime is studied.