Research On Reliability Evaluation Of Stable Degraded Products With Random Shock

Due to the complexity of its operating environment,products are subject to random shocks from inside or outside.The impact of random shocks on the product can be divided into a variety of situations:some shocks have no effect on the product,and some shocks will reduce the performance of the product or the life,or even make the product completely lose its function.The final failure of the product is often the result of the competition between the degradation failure caused by its own steady degradation process and the sudden failure caused by the external random impact,but most of the current reliability research methods simply combined the two results of the study,while ignoring the internal connection between the two processes.In view of this,for the random decay shock,the correlation between the shock process and the degradation process,and the type of multiple shocks,this paper systematically conducts a comprehensive evaluation study on the reliability of the stationary degraded products accompanied by random shocks.The main research content of the paper includes the following aspects:(1)For the working conditions under the impact of random attenuation shocks,and the product's degradation process generates corresponding incentives,a comprehensive failure reliability assessment model with decay random shocks is established.The Wiener process is used to fit the performance degradation process,and then the exponential function is used to describe the attenuation process,considering the functional relationship between the impact response amount and the impact damage amount.The mean value estimation method is used to estimate the drift and diffusion parameters of the performance degradation process and the impact arrival rate and amplitude parameters of the impact process,The least squares estimation is used to estimate the impact attenuation coefficient and damage factor.The example illustrates the rationality and effectiveness of the model.(2)Under the impact of random shocks,the product degradation process will produce a sudden increase in the amount of degradation and accelerate the degradation,the total amount of degradation also will change the sudden failure threshold,establishing the competitive failure reliability evaluation model of the product under the variable degradation rate and the continuous variable failure threshold.Assuming that the sudden failure threshold is a monotonically decreasing linear function related to the total degradation of the product,and the change in the degradation rate is related to the number of impacts,then a competitive failure reliability model for the product is established,and finally the micro engine data from the Sandia National Laboratory MEMS was used for simulation,which proved the feasibility of the model.(3)For the cases where multiple impact types may exist simultaneously in the continuous degradation process,a comprehensive evaluation model of product reliability failure reliability with variable thresholds under multiple impact types is established.The main failure mode of the product when there are multiple shock types in the outside world is analyzed by the variable threshold failure model.The extreme value shock model is used to give the specific expression of the competitive failure reliability model.Finally,the simulation example uses a certain type of radar steering system motor components data to prove the validity and rationality of the model.