高温作用下钢管混凝土构件侧向撞击性能

通过耦合ABAQUS有限元软件中的隐式静态分析和显示动态分析，提出钢管混凝土构件在火灾与撞击联合作用下的数值计算方法，分别对已有钢管混凝土构件的温度场试验、火灾下轴向撞击试验和常温下侧向撞击试验进行数值模拟，以验证本文方法的合理性。在此基础上建立了钢管混凝土构件在不同温度下的侧向撞击有限元模型，分别对不同温度下的挠度和撞击力时程曲线进行对比，采用极值后平均撞击力和吸能系数对高温作用下构件的抗侧向撞击性能进行量化分析，并分析了600 ℃下构件撞击全过程。结果表明:温度对钢管混凝土构件的侧向撞击性能影响明显，随着温度升高，构件跨中挠度大幅增加，撞击时程变长；高温下构件的撞击力时程曲线与常温下差异明显，高温下曲线可分为震荡阶段、下降阶段和卸载阶段；构件主要通过整体弯曲变形吸收落锤的动能，随着温度升高，极值后平均撞击力和吸能系数逐渐降低，表明构件的抗撞击性能逐渐降低，当温度超过400 ℃后，构件抗撞击性能损失严重。

The lateral impact performance of concrete-filled steel tubular (CFST) members at high temperatures

By coupling the implicit static analysis and the explicit dynamic analysis in ABAQUS, a numerical method to simulate the lateral impact process of concrete filled steel tubular (CFST) member in fire is presented. The tests about temperature field, the axial impact under fire and lateral impact at ambient temperature of CFST members are simulated to verify the feasibility of the method, respectively. Based on the proposed method, the finite element analysis (FEA) model of lateral impact of CFST members at different temperatures is developed. The time history curves of mid-span deflection and impact force at different temperatures are compared respectively. The post-extremumequal impact force (F_pe) and energy absorption capacity (μ) are used to quantitatively analyze the lateral impact resistance of the member. Finally, the impact process of the member at 600 °C is analyzed. The results show that the temperature has a significant influence on the lateral impact performance of the member. With the increase of temperature, the mid-span deflection increases and the impact duration is longer. The time history curve of impact force at high temperature is obviously different from that at ambient temperature. And the curve at high temperature can be divided into three stages, including the oscillating phase, the descending phase and the unloading phase. The kinetic energy of the drop hammer is mainly absorbed by the overall bending deformation of the member. The F_pe and μ decrease with the increase of temperature, indicating that the impact resistance of the member decreases. When the temperature of exceeds 400 °C, the impact resistance of the member is seriously lost.