机载燃油泵电应力加速退化建模与试验设计

Modeling and experimental design of accelerated stress degradation of airborne fuel pump

针对传统加速退化模型建立过程中,未考虑应力变化造成失效阈值变化的问题,提出了通过试验建模确立失效阈值的方法.在分析某型机载燃油泵工作机理和物理模型的基础上,设计了从101~130 V的步进电压条件下机载燃油泵压力与流量测量试验,并基于样本分位数构建了机载燃油泵电应力下压力与流量的数学模型;又选取100、105、110、115、120、125 V为工作电压进行了加速退化试验,拟合出不同电应力下机载燃油泵的退化轨迹.最终依据其数学模型估计了机载燃油泵在100、105、110、115、120、125 V工作电压下的失效寿命分别为53 848、43 599、39 269、37 140、26 643、20 522 h,依据逆幂律模型L(U)=A×Un,通过参数拟合建立了机载燃油泵电应力加速退化模型L(U)=1. 329 9×10^12×U^-3. 694 9。

Aiming at that the change of failure threshold caused by stress change is not considered in establishing the accelerated degradation model, this paper proposed a method of determining failure threshold through experimental modeling. Based on the analysis of the working mechanism and physical model of a certain type of airborne fuel pump, this paper designed the pressure and flow measurement test of airborne fuel pump under the stepping voltage from 101 to 130 V, also built the mathematical model of the pressure and flow under the electric stress of airborne fuel pump based on the sample quantile. Afterwards, this paper elected 100, 105, 110, 115, 120 and 125 V as working voltages to carry out accelerated degradation tests, so as to fit the degradation trajectory of airborne fuel pump under different electric stresses. Finally, this paper estimated the failure life of airborne fuel pump under 100, 105, 110, 115, 120 and 125 V to be 53 848, 43 599, 39 269, 37 140, 26 643 and 20 522 h. According to the inverse power law model L(U)=A×U^n, it worked out the acceleration degradation model of the airborne fuel pump under electric stress as L(U)=1.329 9×10^12×U^-3.694 9.