Reliability Analysis Of Gradient And Correlative Variables Of Vehicle Parts

The use of vehicle parts is a process of wear and fatigue.The geometrical dimensions of the vehicle parts will be changed because of the wear factors,meanwhile,the load cycle of vehicle parts will lead to the deterioration of the strength of the vehicle parts.In addition,the geometrical size,strength,load and other basic random parameters are generally correlative.The existence of these factors will inevitably affect the reliability of the structure.In the traditional reliability design model of vehicle parts,the wear,strength degradation and the correlation between parameters are not taken into account,which can only reflect the reliability of the initial stage,but cannot get the rule of the overall reliability change with time,which is not quite consistent with the actual application.Therefore,it is necessary to consider the factors such as wear,strength degradation and correlation between parameters when analysis the reliability of vehicle parts.The main research contents of this paper are as follows:(1)Based on the theory of residual strength of schaff,we considered the strength degradation of vehicle parts under load cycle and the influence of wear on vehicle parts,and the influence of the strength degradation and wear on the parts is analyzed respectively.Finally combined with the strength degradation and wear,the stress limit state equation is established by the stress-strength interference model.(2)Under two conditions of the strength degradation and wear of vehicle parts,the second-order moment and perturbation method are used to analyze the gradual reliability and reliability sensitivity of vehicle parts,and the Monte Carlo Numerical simulation method is applied to verify the stability.(3)The static analysis of specific parts is carried out by the method of setting path and surface by ANSYS Workbench,and the design of experiment is carried out by the Six Sigma analysis module of ANSYS Workbench to obtain the data of the maximum stress of vehicle parts under random variables.Based on the experimental design database,the BP neural networks are constructed to fit the function between the maximum stress and the design variables,finally,the limit state function considered the maximum stochastic stress and strength degradation is constructed to analysis the reliability.(4)Based on the correlation of stochastic variables of vehicle parts,we discussed the influence of correlation coefficients on reliability and reliability sensitivity of vehicle parts combining the perturbation method,the reliability design theory and the sensitivity analysis method.Finally,considering the correlation between the geometrical parameter sizes of vehicle parts,the gradual reliability and reliability sensitivity of vehicle parts are analyzed...