冲击荷载下钢管混凝土柱模型力学性能试验研究

EXPERIMENTAL RESEARCH ON MECHANICAL BEHAVIOR OF CONCRETE FILLED STEEL TUBES MODEL UNDER IMPACT LOAD

为研究冲击荷载下钢管混凝土柱(CFT)的力学性能,采用φ57mm轻气炮实验装置和技术,进行了8个钢管混凝土柱模型的冲击试验及模拟分析计算。测得了不同弹体冲击速度下试件表面的应变时程曲线,获取了试件破坏形态及残余变形,比较了不同弹体冲击速度、试件装夹部位、试件外包约束等因素的影响。结果表明,冲击荷载作用下试件残余变形、应变变化直接与弹体冲击速度有关;受弹体碰撞后,试件冲击端的残余变形最大;装夹部位设在试件中部更能真实的模拟试件受力的真实情况;外包碳纤维对试件的抗冲击性能有一定的改善,尤其是在横向变形较大的部位;钢管混凝土柱模型试件的应变量级很大,环境噪声影响较大,可采用大阻值和大量程应变片提高应变准确度。

The experiments of 8 concrete filled steel tube (CFT) models under impact load were performed by means of 57mm diameter light gas cannon, and simulation analysis was made in order to explore the mechanical property of CFT model. The time-history curve of strain on the steel tube surface, its destructive behavior and permanent deformation were investigated. The affecting factors, such as impacting velocity of projectile body, constraint condition due to wrapping carbon fibers, etc. were considered. Experiment and calculation results prove, that the permanent deformation and strain variation are directly related to the impacting velocity of projectile body; the maximum permanent deformation of the model appears in the region near the impacted end; the position near middle part of the model is considered to be a rational assembly location to simulate the real state of the model, and constraining carbon fibers can improve the shock resistance of the model especially on the parts which are of larger lateral deformation. The wide range strain gauge with large electric resistance should be used to improve the test accuracy, because of the large strain in CFT model and the unfavorable influence of environment noise.