Parameter Sensitivity Analysis And Application Of The Random Structural Response In The Multi-source Random Excitation

Parameters Sensitivity Analysis of vibration system is a method to research and analyze the sensitivity of the status or output of the system when parameters are chenged. As the optimization of vibration system, find the system parameters which have the greatest impact on the system of to be the design variables and change the variables to optimize the synamic features of the system. Parameters sensitivity analysis method has been applied to lots of areas of vibration and noise reduction.There are some uncertainties in engineering problems, and Solving practical problems should use the random vibration theory. There is great significance if Parameters Sensitivity Analysis is used in random vibration system. Random vibration problems include random excitation and random structural vibration. First of all get the mean and variance of random structural system and obtain the parameters sensitivity of random excitation system. Then derive the mean and parameters sensitivity of the response of multi-source random excitation with random structural parameters by the mathod of double state-space decoupling method, Kronecker algebra, unit impulse response method, matrix calculus, the generalized probabilistic perturbation method, matrix perturbation theory, and matrix Taylor Series Deployment.With the development of the highway, four-wheel light vehicle have a wide range of applications because it is flexible, adaptable and cost low. The vibration characteristics of the truck affect the driving conditions, fatigue and even the safety of moving. So use Parameters Sensitivity Analysis method to optimize the four-wheel light ride comfort. Firstly establish multi-body dynamics model of the truck. Secondly take the vibration response which cause fatigue and damage the goods to be the optimization goal.Thirdly select reasonable design variables and optimization methods. Lastly under effective constraints calculate the optimal results. The results must ensure comfort of passengers and the goods integrity.In the modeling process analyze and compare multiple models, and determine the use of ten degrees of freedom vehicle model to study. Get the parameter values of mass, stiffness, damping and relative position by model parameters experiment. Then calculate the mode by experimental results. Compare the mode and modality test results, and fix the model parameters. By defining the random road excitation spectrum, solve the parameters sensitivity of the weighted rms acceleration of the cab response, and use ride comfort design theory to select the design variables. Make the weighted rms acceleration of the cab to be the optimization objective. Select the static deflection, deflection, natural frequency, the relative dynamic load, the damping ratio as constraints, and optimize the ride comfort of four-wheel light truck. The suddent increace of weighted rms of the cab is eliminated in the speed of 40km/h. High speed ride comfort has also been improved.