﻿ 基于故障行为的惯导产品贮存寿命试验设计<sup>*</sup>
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Failure behavior based storage life test design for inertial navigation products
XU Dan, LIN Kunsong, Chen Yunxia
Science and Technology on Reliability and Environmental Engineering Laboratory, School of Reliability and Systems Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China
Received: 2017-06-15; Accepted: 2017-06-23; Published online: 2017-09-15 17:09
Foundation item: National Natural Science Foundation of China (61403010)
Corresponding author. XU Dan. E-mail: xudan@buaa.edu.cn
Abstract: This paper proposed a failure-behavior-model based accelerated degradation test designing method for assessing the storage life of accelerometer for inertial navigation products, which determines test stress levels while lacking of the preliminary experimental data. On the basis of analyzing the product characteristics and main mechanisms, the storage life characteristic parameters and test stress types are determined. An accelerometer failure behavior model which takes the material dispersion into consideration is established to describe the time-varying law. Given the highest stress level, based on the given confidence level and failure behavior model, a simulation accelerated degradation test design method is proposed to determine the lowest and intermediate stress levels with the constraint that the upper bound of degradation under lower stress level is lower than the lower bound of degradation under high stress level. Following the proposed framework, the experimental profile is designed, and then a best test plan is finally obtained. The validity of the proposed method is verified by a case study.
Key words: failure behavior model     inertial navigation products     test design     plan optimization     accelerometer

1 加速度计故障行为模型

 图 1 石英挠性加速度计表头结构 Fig. 1 Structure of quartz flexible accelerometer header

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2 基于故障行为模型的加速退化试验设计方法

2.1 含置信度的故障行为模型包络

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t时刻置信度为(1+γ)/2的的置信区间上下限。uα为标准正态分布的α分位数；σK1t时刻的标准差。

 图 2 含置信度的标度因数退化曲线(γ=90%) Fig. 2 Degradation curves of scale factor with confidence coefficient (γ=90%)
2.2 试验应力水平设计方法

 图 3 T2可选范围确认流程示意图 Fig. 3 Schematic diagram of optional range validation procedure for T2

2.3 确定试验最优方案

 图 4 加速度计标度因数加速退化试验方案优选流程 Fig. 4 Optimization procedure of accelerometer scale factor accelerated degradation test scheme

3 案例分析

 图 5 T2, T3温度可选范围上限时的标度因数退化曲线 Fig. 5 Degradation curves of scale factor under optional range upper limit of temperature T2, T3

 ℃ T2 T3 75 60, 55, 50, 45, 40, 35, 30 70 55, 50, 45, 40, 35, 30 65 50, 45, 40, 35, 30 60 45, 40, 35, 30 55 40, 35, 30 50 35, 30 45 30

 图 6 90℃伪寿命对数正态分布概率图 Fig. 6 Probability graph of lognormal distribution of pseudo life at 90℃

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 图 7 备选方案优化目标函数值 Fig. 7 Optimization objective function value of optional plan
4 结论

1) 本文提出了一种基于故障行为模型的加速退化试验设计方法。以高应力水平下的置信下限与低应力水平下的置信上限不交叉为原则，采用基于仿真的加速退化试验方法，优化确定了试验方案，从而解决了缺乏预试验数据情况下试验设计问题。

2) 以典型惯导产品加速度计为对象，进行了方法可行性和有效性验证。通过主机理分析得到加速度计主要参数标度因数变化的主退化机理为温度作用下的磁钢退磁，并得到描述标度因数应力作用下时变规律的故障行为模型。在加速度计最高温度应力水平为90℃条件下，基于该模型设计加速度计加速退化试验的优选应力为T2=75℃, T3=55℃。该设计方法为提高基于加速退化试验的产品可靠寿命评估精度提供了前提保障。

#### 文章信息

XU Dan, LIN Kunsong, Chen Yunxia

Failure behavior based storage life test design for inertial navigation products

Journal of Beijing University of Aeronautics and Astronsutics, 2018, 44(3): 437-443
http://dx.doi.org/10.13700/j.bh.1001-5965.2017.0408