Storage life evaluation method based on segmented nonlinear Arrhenius model

Abstract

Considering that logarithm linear Arrhenius model is only suitable for a small temperature range,a correction method for the Arrhenius model was given. As the step-down-stress accelerated life testing has the advantages of higher failure rate,less sample size,and simpler testing equipment,an evaluation method used in engineering practice for step-down-stress accelerated storage life testing was provided based on the segmented nonlinear Arrhenius model. A mathematical model for failure data conversion under step down stress based on the segmented nonlinear Arrhenius model was first established. The maximum likelihood function of the whole samples was given. The segmented nonlinear Arrhenius model parameter estimation could then be obtained by employing the genetic algorithm to solve nonlinear equations. Taking the step-down-stress accelerated storage life testing of radar altimeter as an example for analysis,the results of average life expectancy,the failure rate and reliability function based on logarithm linear Arrhenius model accelerated storage life evaluation method,the results based on segmented nonlinear Arrhenius model accelerated storage life evaluation method,and the results from field data were compared. The relative error of the results based on the segmented nonlinear Arrhenius model accelerated storage life evaluation method is within 5%. The efficiency and accuracy of the step-down-stress accelerated storage life evaluation method based on the segmented nonlinear Arrhenius model is verified.