Research On Approximate Model For Dynamic Optimization Of Complex Mechanical Structures

Aiming at the time-consuming problem of the dynamical optimization of complex mechanical structure,taking the muzzle disturbance of vehicle mounted gun as optimization target and the overall structural parameters of vehicle mounted gun as design variables,the dynamical finite element model of vehicle mounted gun was established.Then the methods to extract samples were studied.Various kinds of approximate modeling methods were researched and the forecasting precision of the models was comprehensively compared.Through the method of approximate model combining with Genetic Algorithm,the structural parameters were optimized and the result turned out good,which provided reference and guidance for dynamical analysis,approximate modeling and optimal design of complex mechanical structure.The detailed mesh model of vehicle mounted gun was established.The connection relationship between different parts of gun was studied.The modeling of boundary condition and loads was researched.Then the nonlinear dynamical finite element model of vehicle mounted gun was constructed.Optimal Latin Hypercube Dsign method with three different optimization criterion was compared and studied.Inheritance Latin hypercube Dsign method which considers the distance between training samples and testing samples was proposed.The training samples and testing samples were extracted,based on which,the dynamical finite element model was analysed and the accordingly muzzle disturbance was obtained.The methods of approximate modeling,which includes Response Surface Method.Kriging Method,Artificial Neutral Network Method and Support Vector Machine Method,were studied,along with the selection of key parameters and the impact of parameters selection on forecasting precision of the models.The method to optimize model precision by 10-fold cross validation combining with Genetic Algorithm was proposed,which effectively pomoted the generalization ability of approximate model.With comprehensive consideration of complexity and forecasting precision of approximate models,the most appropriate modeling method was used to construct the approximate model.The mehod of approximate model combining with Genetic Algorithm for structural dynamical optimization of vehicle mounted gun was proposed.With approximate model established and objective function of muzzle disturbance optimization constructed,the dynamical optimization of overall structural parameters of vehicle mounted gun was achieved with Genetic Algorithm.The result showed that the method for dynamical optimization of complex mechanical structure by approximate model combining with Genetic Algorithm is time-saving and effective.