超材料混凝土抗冲击效应数值研究

Numerical study on impact resistance of metaconcrete

作为一种广泛应用的工程材料,混凝土材料抗拉强度低的缺点限制了其应用.当高速冲击荷载作用在混凝土结构上时,由于混凝土的脆性和较低的抗拉强度,结构后部的混凝土通常会产生严重的层裂破坏.因此,有效降低混凝土的层裂破坏对于提高结构性能很重要.近些年学者提出了局域共振超材料,它利用人造微结构的存在能使该超材料呈现出天然材料所不具备的超常物理性质.本文借鉴局域共振超材料的工作原理,通过将混凝土中的部分天然骨料替换为人工骨料超材料来降低冲击荷载下的层裂破坏.通过LS-DYNA,建立考虑随机分布的砂浆、天然骨料和人工骨料的超材料混凝土三维细观模型来进行层裂实验的数值模拟.研究超材料混凝土在冲击荷载作用下的材料性能以及人工骨料的材料属性和几何属性对超材料混凝土动态性能的影响.

It is well known that concrete material is strong in compression while weak in tension.Concrete structure might experience severe spall damage at the rear of the structure when it is subjected to intensive loading.Concrete is usually simulated as homogeneous material without considering aggregate.However,the presence of aggregates has effect on the dynamic material properties of concrete.In recent years,metamaterial has attracted much attention as the metamaterial with artificial microstructures exhibits extraordinary behaviors that cannot find in nature.In this study,the metaconcrete made of locally resonant metamaterial is investigated.Three-dimensional meso-scale model of metaconcrete considering mortar,aggregates and engineered aggregate is developed to simulate spalling test by using LS-DYNA.The accuracy of the numerical model in simulating the spalling tests is verified by comparing the numerical results with the previous studies.The effects of material properties and geometric properties(e.g.elastic modulus and thickness of elastic layer)on the dynamic response of metaconcrete are studied.