Research On Failure Mechanism And Life Prediction Method For Aerospace Relays

In recent years, with the increasing demands on the reliability of aerospacesystems, as one of the components which have the highest failure rate, the life andreliability of the aerospace relay needs to be urgently improved. Therefore, researchon failure mechanism and life prediction method for aerospace relays has significanttheoretical and practical value.From the angle of arc erosion and material transformation, the surfacemorphology of delay contact is observed in the essay. And with the degradationtrend of sensitive parameters monitored in the life test, the failure mechanism andfailure mode of aerospace relay are analyzed. Through the life test for aerospacerelay with resistance, capacitive and inductive load, the failure mechanism andfailure mode are analyzed respectively, and the effects of different load conditionsare compared. Based on the data of sensitive parameters, the failure mechanism ofaerospace relay is discriminated by principal component analysis and Mahalanobisdistance discrimination method respectively.In this essay, the predictive variable and failure threshold under different failuremodes are determined by observing the failure mechanism analysis and thedegradation trends of sensitive parameters. The testing data based on sensitiveparameters in put forward and degradation model of aerospace relay is established.In order to improve the accuracy of degradation models, the methods of outlierseliminating, smoothing process and wavelet transformation are used for denoising ofthe sensitive data. The actual life and predictive life in the degradation model offailure relay are compared to validate the accuracy of the degradation models.In this essay, the reliability and life test system of aerospace relay is designedand developed. The whole system consists of hardware system, lower computersoftware system and upper computer system. The real-time acquisition of contactvoltage, contact current, coil current and the signal of contact voltage drop isaccomplished by hardware system. The date of sensitive parameters calculatedthrough the algorithm in the lower computer software is transmitted to the uppercomputer. Parameters setting, the display and saving of sensitive parameters as wellas failure mode analysis, failure mode discrimination and life prediction of thesubsequent data are accomplished by the upper computer.