| With the rapid development of the automotive industry,the contradiction between the increase of vehicle ownership and the shortage of energy and environmental pollution is becoming increasingly prominent.Vehicle lightweight is also an important way to al eviate the contradiction.In recent years,high strength steel has been more and more widely used in body manufacturing by virtue of its material performance and price advantage.Because the properties of high strength steel are much different from that of ordinary steel,the process of being popularized has also brought many new and complicated problems to the manufacturing process,in particular,the hardening exponent of high strength steel is low,it results in cracking easily,while the yield strength is high,which also leads to a large springback after sheet metal forming.In this paper,the finite element numerical simulation technology is applied to the stamping process design of high strength steel,combining with the response surface agent model method,thus the stamping process of high strength steel is simulated,and combined with the response surface agent model method,the stamping process parameters are optimized and find out the optimal process parameters.At the same time,it is considered that,the initial process parameters usually fluctuate and deviate from the optimal parameter combination in the process of die processing.Considering the parameter fluctuation in the optimization process,a robust optimization model for stamping process parameters of high strength steel is established.The stamping process design and robust optimization of parameters for high-strength steel plate are explored,and the following work is carried out in detail:Firstly,introduced the classification of high strength steel materials and the present state of the application of High strength steel for automobile body at home and abroad,and the research status of high strength steel forming process.In view of the problem of springback of high strength steel,the theories of the researchers at home and abroad for the control of springback are introduced.Secondly,the theoretical basis of stamping finite element method for highstrength steel is systematical y introduced,and the cause and mechanism of quality defects in stamping process of high-strength steel are explained in detail.At the same time,the principle and application of the robust optimization design method are also introduced.Thirdly,introduced the method of agent model,the response surface model is applied to the robust optimization model of sheet metal stamping,and constructed the high nonlinear relation between evaluation index and design variable,and use the Gauss function to construct the radial basis function(RBF)to deal with the residual of the model,so as to improve the response surface model,the accuracy of the agent model is improved without increasing a large number of sample points.Then the method is applied to a high order nonlinear function,and the feasibility of the method is verified.Then,take reinforcement plate of high strength steel front longitudinal beam for a certain type of car as tht research object,introduced the design process of high strength steel stamping process by using Autoform numerical simulation software in detail,then the numerical simulation of stamping is carried out,and the result of stampi ng forming is the basis of the following robust optimization.Finally,based on the above work contents,the stamping process parameters are taken as design variables,and the sufficient constraint function and average springback objective function of cracking,wrinkling and deformation are constructed.Considering the fluctuation of parameters,a mathematical model of 6 robust optimization for sheet metal stamping is established.Finally,the robust optimal solution is presented to the finite element model to verify the practicability of the robust optimization method for improving the quality of high strength steel. |
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