• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2023, Vol. 59 ›› Issue (2): 80-95,103.doi: 10.3901/JME.2023.02.080

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Research on Matching of Variable Modulus Kinematic Hardening Constitutive Models and Decoupling Calibration Strategy for High-strength Steel

DUAN Yongchuan1, SUN Lili1, ZHANG Fangfang1, ZHENG Xuebin2, DONG Rui1, GUAN Yingping1   

  1. 1. College of Mechanical Engineering, Yanshan University, Qinhuangdao 066004;
    2. Jingtang Technology Center, Shougang Research Institute of Technology, Beijing 100043
  • Received:2021-09-05 Revised:2022-05-30 Published:2023-03-30

Abstract: Higher strength of high-strength steel can be obtained by controlling microstructure, but the microscopic uneven deformation and micro-induced plasticity mechanism of different grades of high-strength steel are different, which makes the unloading and reverse loading behavior of high-strength steel more complicated and increases the difference between grades. For this reason, a systematic strategy of model adaptive matching and parameter decoupling matching to achieve accurate prediction of high-strength steel springback is given. Firstly, a hybrid hardening model of power function and exponential function is proposed.Based on the hybrid hardening model, the bending moment balance equation for free bending load and curvature constraint equation are raised. In view of the variable modulus model, the integral equation of the section elastic bending moment is established. A sub-optimization model is established to reversely identify the unloading parameters basing on the loading and unloading analytical models. The matching strategy including variable modulus linear and nonlinear kinematic hardening models and variable modulus kinematic hardening models with boundary surface is determined. Based on the experimental data of tension and compression, free bending and uniaxial tension, the optimization sequence of the corresponding constitutive sub-optimization model parameters is determined, and a systematic strategy of constitutive matching and its parameter decoupling calibration is formed finally, and calibration library is developed on the basis of the Fortran language. A prediction model for U-shaped bending parts and arc-shaped bending parts is established, and the recognition results and springback prediction results of DP980 and DH980 high-strength steels at different strain levels are compared and analyzed. The decoupling calibration strategy is verified. Not only the correlation of data of different grades of high-strength steel but also the accuracy and stability of the model under the same grade is greatly increased. It lays the foundation for the research on the unified self-identification method of material properties in view of data.

Key words: constitutive matching, bending springback, decoupling calibration, optimized recognition, high-strength steel

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