Reliable life prediction models for various material damage processes

Abstract

Service failures in most of the engineering systems (structures, machines, or components) are caused by a variety of material degradation processes which leads to the gradual decline in the quality and performance of the system, and ultimately causes the failure of the system. The life of a component is terminated when the damage D(t) reaches or exceeds a limiting value which is the critical level D₁ i.e., failure occurs when D(t)≥D₁, where D(t) represents certain manifestation of damage at time t. The time dependent stochastic characterization of damage functions observed in different types of material damage processes is presented and the corresponding reliability models are developed as well as the link between the parameters of the damage processes and the reliability models is established. These damage functions and reliable life prediction models are developed for several irreversible material degradation processes, such as wear, corrosion, fouling and creep. These reliability models when incorporated in the process of decision making helps to select the best among the available technical alternatives of replacing or maintaining the existing system, as well as to compare the reliability of competing systems supplied by different manufacturers.