Abstract: A forecasting method based on the environmental load spectra is proposed for predicting the lifetime of missile components under time-varying storage environment. Normal and Gamma distributions are used to model the load spectra for collected temperature and humidity data, respectively. A three-parameter Weibull distribution is utilized to fit the time of failure, then the parameters, which are dependent on environment, are determined using acceleration factor constant principle. Furthermore, a simplified generalized Eyring model is used to establish the relationship between the time-varying environment and the reliability model. A case study is provided to validate the effectiveness of the proposed method. The results show that the proposed method can be used to reduce the prediction error compared with the traditional prediction method that takes the average environment as varying environment.

Key words: ordnance science and technology, lifetime prediction, varying environment, load spectrum, three-parameter Weibull distribution, acceleration factor constant principle