Strain-hardening cementitious composites (SHCC) have been reported in several studies to exhibit in several studies to exhibit high toughness even under extreme dynamic loads. To understand such dynamic behavior of SHCC, this study extends a previously developed rate-dependent lattice model by introducing a non-local formulation of the fiber-matrix interface behavior. The Voronoi-cell lattice model, representing the cementitious matrix, employs an explicit time integration scheme and a visco-plastic unit to account for the inertia effect and Stefan effect. Additionally, randomly-distributed short fibers were modeled using an analytical model of shear stress transfer at the fiber-matrix interface. The proposed numerical model successfully simulated the direct tensile behavior and multiple cracking patterns of SHCC, revealing distinct rate-dependent failure characteristics. Through a simple parameter fitting process, the model accurately predicted the dynamic increase factor (DIF) of strength and strain capacity of high-speed tensile experiments. Furthermore, the numerically evaluated rate dependency of the fiber-matrix interface exhibited identical trends to previous experimental studies. Finally, the influences of fluctuations in the applied strain rate during actual high-speed loading tests and the random dispersion of fibers were assessed.

多项研究表明，应变硬化水泥基复合材料（SHCC）即使在极端动态载荷下也能表现出高韧性。为了理解 SHCC 的这种动态行为，本研究通过引入纤维-基体界面行为的非局部公式来扩展先前开发的速率相关晶格模型。代表水泥基体的Voronoi-cell 晶格模型采用显式时间积分方案和粘塑性单元来解释惯性效应和 Stefan 效应。此外，使用纤维-基体界面处剪切应力传递的分析模型对随机分布的短纤维进行建模。所提出的数值模型成功模拟了 SHCC 的直接拉伸行为和多重裂纹模式，揭示了明显的速率相关失效特征。通过简单的参数拟合过程，该模型准确预测了高速拉伸实验的强度和应变能力的动态增加因子（DIF） 。此外，数值评估的纤维-基体界面的速率依赖性表现出与之前的实验研究相同的趋势。最后，评估了实际高速加载试验中施加应变率波动和纤维随机色散的影响。