A finite deformation mechanism-based thermodynamically consistent constitutive framework is presented for describing the dynamic behaviors of brittle materials under impact loading. The framework is developed based upon a multiplicative decomposition of the deformation gradient in terms of multiple mechanisms, including recoverable elasticity, crack-induced damage, and other inelastic mechanisms such as subgrain and granular plasticity. The finite deformation kinematics that captures the multiple mechanisms is structured within a thermodynamically consistent framework, and the consequent coupling of the various mechanisms is articulated. Specific constitutive equations are formulated for a Mie–Grüneisen equation of state, micromechanics-based dynamic-fracture-induced damage growth, subgrain or lattice plasticity for slip and other deformation modes, and granular plasticity for granular flow and pore collapse post-fragmentation. Using hot-pressed silicon carbide (SiC-N) as the model material, this integrative model is calibrated using available experiments that interrogate specific mechanisms. The effects of loading rate, the influence of confinement, and the path-dependent constitutive behaviors of the material predicted by the model are demonstrated. The model performance at the application scale is then evaluated by simulating previously performed sphere-on-cylinder impact experiments.

提出了一种基于有限变形机制的热力学一致本构框架，用于描述脆性材料在冲击载荷下的动态行为。该框架是基于变形梯度在多种机制方面的乘法分解而开发的，包括可恢复弹性、裂纹引起的损伤和其他非弹性机制，如亚晶粒和粒状塑性。捕捉多种机制的有限变形运动学是在热力学一致的框架内构建的，并且各种机制的后续耦合被阐明。为 Mie-Grüneisen 状态方程、基于微观力学的动态断裂引起的损伤增长制定了特定的本构方程，滑移和其他变形模式的亚晶或晶格塑性，以及碎裂后颗粒流动和孔隙坍塌的颗粒塑性。使用热压碳化硅 (SiC-N) 作为模型材料，该集成模型使用询问特定机制的可用实验进行校准。展示了加载速率的影响、约束的影响以及模型预测的材料的路径相关本构行为。然后通过模拟先前执行的球体对圆柱体冲击实验来评估模型在应用范围内的性能。该综合模型使用询问特定机制的可用实验进行校准。展示了加载速率的影响、约束的影响以及模型预测的材料的路径相关本构行为。然后通过模拟先前执行的球体对圆柱体冲击实验来评估模型在应用范围内的性能。该综合模型使用询问特定机制的可用实验进行校准。演示了加载速率的影响、约束的影响以及模型预测的材料的路径相关本构行为。然后通过模拟先前执行的球体对圆柱体冲击实验来评估模型在应用范围内的性能。