混凝土HJC本构模型参数的研究

Research on the material constants of the HJC dynamic constitutive model for concrete

运用非线性有限元动力分析软件LS-DYNA模拟了混凝土SHPB试验。将试验采集的入射波数据作为压杆的端面载荷,模拟条件尽量符合试验条件,确保模拟精度。将数值模拟与试验结果相结合,研究了混凝土HJC模型参数的确定方法,得到了C60混凝土的相关计算参数,模拟结果得到的应力-应变曲线与不同应变率下混凝土SHPB试验应力-应变曲线吻合较好。分析了HJC模型的本构特性,比较了与金属JC模型的差异与共性,讨论了HJC模型存在的问题。研究结果表明,未考虑混凝土弹性响应的应变率效应,横向效应的影响与采用的失效方式密切相关。

The numerical simulation on SHPB tests of concrete are carried out with dynamic finite element software LS-DYNA.To ensure the conditions of simulation being consistent with the test,the incident pulses collected from experiment are directly used as the surface loading data of simulation.Through combines the numerical simulation with the experimental results,the determination method of constants of HJC model is analyzed,and the nstants of C60 concrete are obtained.The stress-strain curves reconstructed from simulation are in good agreement with the experimental results under different strain rates.The constitutive characteristic of HJC model and the difference with the JC model for metal materials are analyzed.Some questions about HJC model are discussed:the strain rate effect of elastic response is not taken into account in the model,the transverse effect relates with the selected failure type closely.