Research On Temperature Cyclic Stress Accelerated Degradation Modeling And Test Plan Design

Electrical connector is the key component of the transmission of power and signal in model system.It can achieve rapid electrical connections and separation among equipment,instrument and cable,all bay sections and classes cabin,as well as models and ground.For the reliability test evaluation method of the electrical connector,the development of the constant stress accelerated life test method is more mature currently.However,in engineering,due to the lack of the mature technology to monitor the performance parameters of the electrical connectors,and the time limits of the testing device to the predetermined stress level,it can't be perfectly restored to a constant stress load,which makes the actual testing profile of the electrical connector to be a cyclic stress,and the results of the experimental data are skewed,and the reliability level of the product is not accurate.For this issue,this article is subject to the Y11P-1419 low-frequency round electrical connector,Studies the failure mechanism of the electrical connector in the temperature cycle.And starting from the microscopic Angle of electric connector contact failure mechanism,electric connector is established under the effect of cyclic stress temperature accelerated degradation model,put forward the constant stress and the cyclic stress accelerated test plan between the equivalent criterion.Based on the equivalent criterion,the experiment scheme of temperature cycling stress is designed.Finally,the equivalent temperature cycle stress acceleration degradation test scheme is simulated and evaluated,got more joint engineering practice and time-consuming shorter cyclic stress testing scheme optimization,and provides guidance for the implementation of an actual constant stress acceleration test in the electrical connector project.This dissertation consists of six chapters,as follows:Chapter one discusses the background and significance of this research firstly.Secondly,main ideas and research contents are put forward after studying following three aspects home and abroad: reliability test methods,accelerated degenerate test technology and cyclic temperature stress accelerated degradation test of electrical connector.Chapter two analyses the failure mode of the electrical connector when the test section is subjected to periodic cyclic temperature stress in test profile,and suggests that contact failure is the main failure mode of electrical connector in this case.Meanwhile,the degradation of contact resistance under cyclic temperature stress is studied from the apparent physical chemistry level,and determine that the main reason for the increase of contact resistance is the growth of oxide film layer and the fretting wear effect.In chapter three,from the aspect of the contact of electrical connector to the apparent physical chemistry,the quantitative relationship between contact resistance and contact with the parameters of structure dimension coating is studied.Then the accelerated degradation equation of contact resistance is given,which,combining with contact pairs' life distribution,establishes a statistical model for accelerated degradation of the cyclic temperature of electrical connector.Chapter four proposes the optimization design of the constant-additive degenerate test scheme for the two stress levels and the corresponding optimal test plan.And designs the cyclic stress acceleration degradation test scheme based on the principle of contact resistance degradation.Chapter five firstly uses the MLE and MonteCarlo simulation method to generate the pseudo-data of constant stress and cyclic stress acceleration degradation test scheme.Then taking the expectation and standard deviation of the pseudo-variance of the median life as the characterizing quantity,the paper compares the accuracy and robustness of the two schemes and verifies the rationality of the equivalent scheme.Chapter six summarizes the work contents of the paper and gives some Suggestions for further research directions.