冲击荷载作用下混凝土动态力学性能研究

Study on Dynamic Mechanical Properties of Concrete under Impact Load

为了探讨混凝土在冲击荷载作用下的动态力学性能,应用有限元分析软件对不同冲击速度下,C30、C40及C60混凝土的SHPB试验进行了模拟分析。通过数值模拟得到了不同速度条件下的应力-应变曲线及能量时程曲线并分析了试件的破碎过程。结果表明:C40混凝土与C60混凝土的峰值应力比C30混凝土分别高了20.8%与31.6%,提高混凝土的强度等级可以提高混凝土结构的抗冲击性能。冲击速度为10 m/s与15 m/s时,混凝土的应变率分别是冲击速度为5 m/s的3.2与4.7倍,表明混凝土是一种应变率敏感型材料。能量时程曲线总体上分为3个阶段:前期稳定阶段、中期增长阶段与最后稳定阶段。冲击荷载作用下,混凝土先从边缘由外向内破裂,并在内部产生劈裂破坏。

In order to investigate the dynamic mechanical properties of concrete under impact load,finite element analysis software was used to simulate the SHPB tests of C30,C40 and C60 concrete under different impact velocities.The stress-strain curves and energy time-history curves at different velocities were obtained by numerical simulation,and the crushing process of the specimen was analyzed.The results show that the peak stress of C40 concrete and C60 concrete is 20.8%and 31.6%higher than that of C30 concrete,respectively.Improving the strength grade of concrete can improve the impact resistance of concrete structure.When the impact velocity is 10m/s and 15m/s,the strain rate of concrete is 3.2 and 4.7 times that of 5m/s,respectively,indicating that concrete is a strain rate-sensitive material.The energy time history curve is generally divided into three stages:the initial stable stage,the mid-term growth stage,and the final stable stage.Under impact load,concrete breaks from the edge from outside to inside first,and splits inside.