混凝土圆柱体试件在低速冲击下动力效应的研究

为研究混凝土圆柱体试件在冲击荷载作用下的动力效应，利用落锤冲击试验机，对混凝土圆柱体试件在应变率100~101/s范围内进行轴向冲击试验，并采用混凝土连续面盖帽模型（CSCM）对试验过程进行数值模拟。试验中测量不同冲击速度及冲击边界下的锤头冲击力、试件轴向应变时程曲线，获取了试件破坏形态及破坏过程的高速影像，比较分析了不同冲击速度及边界条件下，试件应力、应变峰值，应变率及动力增强系数（DIF）的变化规律。结果表明：随冲击速度的增加，试件的应力、应变峰值，应变率及动力增强系数都呈增加的趋势，冲击力作用时间则减小。混凝土平均强度与冲击速度呈抛物线关系，应变率则与冲击速度呈线性关系。模拟结果表明，CSCM混凝土本构模型在低速冲击范围内，有很好的计算精度，模拟破坏形态与试验结果吻合良好。

Dynamic behavior of concrete cylinder specimens under low velocity impact

In order to research the dynamic behavior of concrete under low velocity impact, an experimental study was carried out on concrete cylinder specimens subjected to axial impact at strain rate of 100~101/s. Numerical simulations were also conducted with LS-DYNA by using continuous surface cap model (CSCM). The time-history curves of the impact load and the cylinder’s strain under various impact speeds and boundaries were measured. The failure process was captured by a high speed video camera. The test results show that: The peak load, the strain at peak load and the dynamic increase factor (DIF) increase with impact velocity but the impact force duration decrease with that. The curve of concrete average strength shows a shape of parabola with the impact velocity, and the relationship between the strain rate and the impact velocity is approximately linear. The simulation results show that the CSCM concrete constitutive model has a good precision in low-speed impact range, and the simulation failure modes also show a good consistency with the experimental results.