An Improved Time-Variant Reliability Method for Structural Components Based on Gamma Degradation Process Model

The study on reliability of an aging structural component considers the impact of time, by virtue of the complexity of the structural reliability caused by the random and temporal characteristics of strength and stress. This paper proposes an improved time-variant reliability model to meet the requirements for engineering cases. This model is featured by consideration of the stochastic process of strength degradation, in addition to the conventional stochastic process of stress. This paper first establishes the model based on the semi-stochastic-process. The parameters are then determined accurately based on the model of Gamma degradation process with independent increments. Finally, our method is applied to a typical engineering case of ship structures in marine environments. The case study shows that the improved method can avoid the redundant and complex calculations and obtain accurate reliability results. Therefore, our method is proved to be exceptionally effective for engineering applications.