弹体高速冲击载荷下钢筋混凝土的破坏行为实验与细观数值模拟

Experimental and mesoscale numerical investigation on the failure behavior of reinforced concrete under projectile-impact loading

钢筋混凝土在土木工程与国防领域具有广泛而重要的应用,且存在明显的尺寸效应,有必要进行大尺寸侵彻实验研究其在高速冲击下的动态响应.本文开展了100 mm大口径卵形弹高速侵彻钢筋混凝土靶的实验,并对靶体的破坏模式、侵彻深度和开坑直径进行了详细分析.由于钢筋的加入导致混凝土具有更为复杂的非均质性和各向异性,各组分的变形、破坏和相互作用对混凝土力学特性产生重要的影响.基于Voronoi技术提出了一种钢筋混凝土三维细观快速并行建模方法,解决了骨料大规模投放以及钢筋和骨料交叉检测的难题,并结合K&C模型对实验工况进行了细观数值模拟,得到了靶体和钢筋的破坏模式、弹体侵彻深度以及弹道偏转,实验结果与数值模拟结果吻合良好,说明该细观模型能够有效和准确地预测钢筋混凝土的破坏行为.

Reinforced concrete is widely used and plays important roles in civil engineering and national defense.It also suffers from an obvious scale effect.Conducting a large-scale penetration experiment is necessary to study the dynamic response of reinforced-concrete under impact loading.In this study,experiments were conducted for a 100-mm large-caliber ovoid projectile to penetrate reinforcedconcrete targets at high speed.The damage mode,penetration depth,and crater diameter of the target were analyzed in detail.Owing to the reinforcement,concrete exhibits more complex heterogeneity and anisotropy,and the deformation,damage,and interaction of each component indicate an important effect on the mechanical properties of concrete.A fast and parallel modeling method of 3D mesoscale reinforced-concrete model based on the Voronoi technique was proposed,which solved the problems of large-scale arranged aggregates and intersection detections between the reinforcement and aggregates.The mesoscale numerical simulations were conducted in combination with the K&C model,and the effects of the projectile hitting and not hitting the reinforcements on the penetration depth,crater diameter,and ballistic trajectory were analyzed.The damage mode of the slabs and reinforcements,penetration depth of the projectile,and trajectory deflection were obtained.The numerical results show good agreement with the experimental results,which indicate that the mesoscale model can effectively and accurately predict the failure behavior of reinforced-concrete.