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基于累积损伤等效方法提出一种能够描述产品性能非线性退化过程的分段非线性加速退化模型(SNADM,Segmented Nonlinear Accelerated Degradation Model),有效解决了产品性能退化率为时变函数时其寿命难以准确评估的问题.推导了总体累积退化量函数的分段表达式,结合非线性函数和加速方程得到SNADM的表达式;用数值迭代法对SNADM进行参数辨识进而对贮存条件下产品退化轨迹统计量函数进行外推,由产品退化量分布随机过程类型确定可靠度函数,再结合失效阈值对产品贮存寿命进行评估.对某导弹制冷器进行了步降应力加速退化试验,评估结果验证了该方法的有效性和正确性.
Based on the cumulative damage equivalent method, a Segmented Nonlinear Accelerated Degradation Model (SNADM) is proposed to describe the non-linear degradation process of product performance, which effectively solves the problem of difficult life span when product degradation rate is a time-varying function And the accurate evaluation of the problem.Analysed the segmented expression of the total cumulative degradation function, the expression of SNADM is obtained by combining the nonlinear function and the acceleration equation. The numerical iteration method is used to identify the parameters of SNADM and then the product degradation trajectory statistics Function, the reliability function is determined by the random process type of product degeneration quantity distribution, and the storage life of the product is evaluated in combination with the failure threshold.The step-down stress accelerated degradation test of a missile chiller is carried out, and the evaluation results verify that the method Validity and correctness.