• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2021, Vol. 57 ›› Issue (22): 60-70.doi: 10.3901/JME.2021.22.060

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Inverse Determination Method of Johnson-Cook Model Parameters Based on the Stress State Test of Notched Specimens

RU Yifan1,2, ZHANG Lele1,2, LIU Wen1,2, CHEN Geng1,2, DOU Weiyuan1,2   

  1. 1. School of Mechanical and Electronic Control Engineering, Beijing Jiaotong University, Beijing 100044;
    2. National International Science and Technology Cooperation Base, Beijing Jiaotong University, Beijing 100044
  • Received:2021-05-13 Revised:2021-11-06 Online:2021-11-20 Published:2022-02-28

Abstract: Johnson-Cook model is one of the material models suitable for metals with high strain rate, large deformation and strong dynamic load. The determination of parameters corresponding to the material is the key to the application of the model. Since the influence of complex stress state on material properties is not considered, when the model determined by traditional method is used for simulation, there is a significant difference between the calculated results and the actual situation under different stress conditions. Aimed at reduction of such difference, the notched specimens of 6005A-T6 aluminum alloy are designed to characterize different stress states, and the quasi-static uniaxial tensile tests are carried out under the condition of strain rate 4×10-4 s-1. Then, an inverse determination method based on genetic algorithm is proposed, in which the test data under different stress states are included in the training set of genetic algorithm. Using Matlab programming, the data interaction and process integration of optimization algorithm and LS-DYNA simulation are realized. By running the program, the optimal solution of model parameters is obtained. The results show that the model parameters obtained by this method make up for the shortcomings of traditional methods. In the complex stress state, it has better applicability.

Key words: Johnson-Cook constitutive model, genetic algorithm, model parameters determination, 6005A-T6 aluminum alloy

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