【摘要】 混凝土材料产生的应变率效应会改变其在冲击荷载作用下的动态损伤过程。为此，基于键型近场动力学方法，通过改进力密度函数使其能够准确表征混凝土结构受力与动态破坏机制间的联系，建立了刚性圆柱体荷载作用下混凝土板损伤破坏过程的三维数值计算模型，并结合试验结果验证了该模型的有效性。最后，探讨了冲击荷载作用下初始冲击速度、刚性圆柱体直径以及混凝土板厚度等因素对裂纹扩展机制及结构破坏形态的影响。随着初始冲击速度的提高，混凝土板的破坏程度显著增加，裂纹网络由局部向大范围辐射扩展；圆柱体直径的增大显著扩大了混凝土板的损伤范围和裂纹复杂度，增强了材料的动态强度和能量分散能力；混凝土板厚度的增加使损伤范围先扩大后缩小，较厚板材在高应变率下更有效地阻挡和分散冲击能量，同时导致损伤形态更复杂。更多还原

【Abstract】 The strain rate effects in concrete materials alter their dynamic damage processes under impact loading. To investigate this, a three-dimensional numerical model of concrete slab damage under rigid cylindrical loading was developed using a bond-based peridynamic method. The force density function was improved to accurately represent the relationship between stress distribution and dynamic failure mechanisms in concrete structures, and the model’s validity was confirmed through experimental results. Finally, the influence of initial impact velocity, rigid cylinder diameter, and concrete slab thickness on crack propagation mechanisms and structural failure modes under impact loading was examined. The results indicate that as the initial impact velocity increases, the extent of concrete slab damage significantly intensifies, with the crack network evolving from localized to widespread radiative patterns. An increase in cylinder diameter markedly enlarges the damage area and crack complexity of the concrete slab, enhancing the material’s dynamic strength and energy dissipation capability. Additionally, increasing the thickness of the concrete slab causes the damage area to first expand and then contract, as thicker slabs more effectively block and disperse impact energy under high strain rates, while also resulting in more complex damage morphologies.更多还原