Storage reliability assessment for missile component with degradation failure mode in a temperature varying environment

A missile will experience transportation, storage, detection, maintenance and readiness repeatedly in its storage period, during which the environmental temperature is not constant, but dynamically changing within a certain range. For some missile components with performance change, it is necessary to consider the influence of varying environment on its storage reliability. Therefore, this paper presents a storage reliability assessment method for a storage environment where temperature is varying. Firstly, by analyzing the characteristics of missile components, the degradation process is modeled as a Wiener process with nonlinear drift. Based on the model, the life distribution under test environment is proposed. Then, Gamma distribution is chosen to fit the temperature distribution. On this basis, a proportional hazards model is used to describe the impact of varying temperatures on the product storage reliability, thus deriving the unconditional probability density function of its storage life. Finally, model parameters are assessed using the maximum likelihood method. An example is given to illustrate the effectiveness of the method.