Research On Probability And Interval Hybrid Uncertainty Analysis And Optimization Of Passenger Cars

Uncertainty is widely existed in acoustic-solid coupling systems,so it is of great practical significance to carry out research on uncertainty analysis and optimization of acoustic-solid coupling systems.The traditional prediction of acoustic characteristics is based on numerical calculation under certain material characteristic parameters,geometric parameters and boundary conditions.However,in practical engineering,the manufacturing errors,measurement errors and other factors often lead to the uncertainty of the system's material parameters,geometric para meters and boundary conditions.Therefore,it is necessary to study the uncertainty of the vibo-acoustic system.Based on the key research and development program o f Hunan province,this paper studies the analysis and optimization of vibro-acoustic coupling system for a certain type of bus.This paper analyzes and optimizes the vibro-acoustic coupling system of passenger cars from stochastic uncertainty,interval unc ertainty model to stochastic and interval hybrid uncertainty model.The main research contents of this paper are as follows:(1)Based on the stochastic uncertain model,the analysis method of stochastic uncertain vibro-acoustic coupling system based on finite element simulation is studied.Based on the interval uncertainty model,an enhanced optimal Latin hypercube sampling method(EOLHS)is proposed and applied to the analysis of interval uncertainty vibro-acoustic coupling model.(2)In view of the fact that there are both probability uncertain variables and interval uncertain variables in the vibro-acoustic coupling system,this paper studies the analysis method of the probability and interval hybrid uncertain acoustic-solid coupling system,and proposes the double-cycle EOLHS-MC method to be used in the calculation of the mixed uncertain system.The analysis efficiency of stochastic and interval hybrid uncertain systems is improved effectively.(3)A vibro-acoustic coupling model of passenger car is established by finite element method.An idling vibration and noise experiment was carried out;and the engine excitation was applied to the finite element model to get the virtual simulation results.The accuracy of the finite model was verified by comparing the result with the experiment result.Response surface method,Kriging method and elliptic basis neural network method are respectively used to construct the approximate model of acoustic response of passenger cars.The advantages and disadvantages of different approximation techniques are compared.Finally,an approximate model of acoustic field response and structural mass response of the bus is established by combining the elliptic basis neural network model and the optim al hypercube sampling method.The error analysis of the approximate model is carried out.The results show that the approximate model has higher fitting accuracy and can be used to replace the finite element model.(4)The optimization research of stochastic and interval hybrid uncertain vibroacoustic coupling system is carried out.Combining the robust optimization theory and the hybrid uncertainty analysis method,a robust optimization method for stochastic and interval hybrid uncertain vibro-acoustic coupling system based on double-cycle EOLHS-MC method is proposed.Simulated annealing algorithm is used to optimize the robust optimization model,which obtained the best design scheme.The results show that,compared with the traditional optimization design,the robust optimization method not only improves the response performance of the system but also improves the robustness of the system.