Material Parameter Identification Of The Stamping Forming Plate Of Advanced High Strength Steel Based On Bayesian Inference

Accurate mechanical analysis of vehicle body must be based on accurate material performance parameters. Due to the distinctive difference between the material properties of the stamping forming steel plate and the original sheet as well as the difficulty of using the present methods to determine the material property parameters,it is extremely necessary to study a new method which is suitable to determine the property parameter of the stamping forming steel plate.Considering that the traditional tensile test method is not suitable for the material parameter identification of the stamping forming steel plate and the mixed numerical experimental method ignores the problem of the uncertainty, in this paper, based on the hardness tests results the specimen is being partitioned and the Bayesian approach is being introduced into the material parameter identification of the stamping forming AHSS(DP590) plate, and this paper mainly includes the following aspects:(1) The research status of simulation analysis which considers the stamping forming effects and the common methods of material parameter determination are discussed thoroughly, based on which the Bayesian material parameter inverse method is being selected as the approach to identify the stamping forming plate material parameters in this paper; From the view point of stamping forming mechanisms, the main factors which influence the stamping forming plate material properties are elaborated.(2) In order to study the influence of stamping process on the AHSS property specifically, a dual phase steel-DP590 is chosen as the experimental material and a specimen which refers to the reinforce part of the B pillar in one particular vehicle is designed and manufactured. Then, the micro-indentation tests by using Tribo Indenter system are conducted along the contour line of the specimen, according to the hardness results of which the specimen is being divided into four regions.(3) In order to take the uncertainty in the inverse process into account, the Bayesian inference is being introduced into the inverse process. The robust inverse problem method-Bayesian approach is used to identify the material parameters of different regions based on the indentation test data in this paper. And Markov chain Monte Carlo(MCMC) method is used to calculate the Bayesian inference anduncertainties.(4) In order to verify the material parameters of the four regions by Bayesian approach, two verification methods are presented in this paper. Firstly, the acquired parameters are brought into the indentation FE model and indentation simulations are conducted. The simulation results are compared with the indentation experimental data. Secondly, the uniaxial tensile tests based on DIC measurement technique of the stamping forming specimen are conducted. Simultaneously the tensile test FE model is built and the acquired parameters are brought into this model. The simulation results are compared with the tensile test experimental results. The results demonstrate that the obtained mechanical properties allow well correlating the simulation to the experiments.