摘要:
为研究爆炸冲击荷载作用下剪切强度效应和应变率效应对混凝土类材料状态方程的影响，基于水泥砂浆静水压缩和平板撞击两类状态方程行为实验，利用Kong-Fang混凝土类材料流体弹塑性模型和LS-DYNA中光滑粒子伽辽金（Smoothed particle Galerkin, SPG）算法，建立能科学表征混凝土类材料包括剪切强度效应和应变率效应在内的复杂动态力学行为的高精度数值模型。在此基础上，定量分析剪切强度效应和应变率效应对混凝土类材料状态方程行为的影响，并指出剔除平板撞击实验中剪切强度和应变率耦合效应所面临的困难。结果表明：利用Kong-Fang模型和SPG算法可精确模拟混凝土类材料包括剪切强度效应和应变率效应在内的复杂动态力学行为；为实现爆炸冲击荷载作用下混凝土类材料在高-中-低压下动态力学行为的精细化模拟，要依据可靠的状态方程行为实验数据建立混凝土类材料宽广压力范围状态方程；在利用平板撞击实验数据标定状态方程参数时，须剔除剪切强度和应变率耦合效应的影响；建立混凝土类材料宽广压力范围状态方程存在悖论，利用数值迭代策略可能是解决困难的有效手段。研究结论可为后续利用数值迭代策略剔除剪切强度效应和应变率效应对混凝土类材料状态方程的影响，并进一步建立爆炸冲击荷载作用下混凝土类材料高精度宽广压力范围状态方程提供依据。
Abstract:
To investigate the shear-enhanced effect and strain-rate effect on the equation of state (EoS) of concrete-like materials subjected to blast and impact loadings, high-fidelity numerical simulations were performed based on two types of EoS behavior tests for cement mortar, including hydrostatic compression test and flyer-plate impact test. These simulations employed the Kong-Fang hydro-elasto-plastic model for concrete-like materials and implemented using the smoothed particle Galerkin (SPG) algorithm in LS-DYNA, enabling accurate reproduction of complex dynamic mechanical behaviors, including the shear-enhanced effect and strain-rate effect. Based on the high-fidelity numerical simulations described above, a quantitative analysis was conducted to investigate the influence of the shear-enhanced effect and strain-rate effect on EoS behavior of concrete-like materials, and the challenges associated with eliminating the shear-enhanced and strain-rate coupling effects in flyer-plate impact tests were systematically identified. The results demonstrate that the Kong-Fang model, when combined with the SPG algorithm, can accurately simulate the complex dynamic mechanical behaviors of concrete-like materials, including shear-enhanced effect and strain-rate effect. To achieve high-precision simulation of dynamic mechanical behaviors of concrete-like materials subjected to blast and impact loadings across high-medium-low pressure ranges, it is essential to establish an EoS with wide-range pressure based on experimental data from EoS behavior tests. However, shear-enhanced and strain-rate coupling effects should be eliminated when using flyer-plate impact test data to calibrate the EoS parameters. A paradox arises in the establishment of EoS with wide-range pressure for concrete-like materials, and the application of numerical iteration correction methodology may represent an effective approach to resolving this challenge. These findings provide a theoretical foundation for the future development of a numerical iteration correction methodology to eliminate the shear-enhanced effect and strain-rate effect on the EoS of concrete-like materials, thereby facilitating the establishment of a high-precision EoS with wide-range pressure for concrete-like materials subjected to impact and blast loadings.
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