Study on parameter acquisition and optimization methods of JH-2 constitutive model for ceramic

In this study, based on AD995 and sapphire, the method of obtaining and optimizing the key parameters of the Johnson-Holmquist constitutive model (JH-2 model) for typical brittle materials was established. The parameter acquisition method was optimized by analyzing the limitations of the traditional parameter acquisition method. The value ranges of the intact strength parameters were calculated using the results of the mechanical property tests of the materials; the well-fitted intact strength parameters (A, N, C and T) were obtained by combining with the parameter optimization procedure. The sensitivity of the dynamic compression test and the penetration process to the damage-related parameters (B, M, D1 and D2) was analyzed by numerical simulation methods. The damage-related parameters in the JH-2 model were obtained using a chaotic global optimization algorithm combined with numerical simulations of dynamic compression tests and penetration tests. The calculation accuracy of the traditional and optimized parameters were compared by numerical simulation results of penetration tests for different ceramic composite structures. The simulation results of the optimized parameters basically match with the experimental results, and the calculation accuracy is much higher than that of the traditional parameters, which verifies the effectiveness and superiority of the parameter optimization method.