地震作用下同心钢管支撑的有限元建模
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摘要
如果使用不可靠的支撑系统,钢结构建筑在地震时易受到损害。地震活跃区域的钢结构建筑应使用同心支撑系统。同心支撑部件的失效多发生在中等长度的塑性铰处。建立一个精细的有限元模型来模拟包括断裂在内的循环荷载下支撑部件的滞回性能。模型所提供的滞回性能与之前的试验和最近两个试验所得到的滞回性能相近。试件所受的荷载模式不同。初始缺陷影响前屈曲和第一次屈曲循环,但对接下来的循环没有影响。方钢管的初始屈服应力越大,局部屈曲发生得越早。发生断裂的中等长度塑性铰的受压角-腹板的外表面累积塑性应变大于内表面。产生的明显局部转动可作为发生断裂构件的塑性应变。
Steel buildings are susceptible to damage during earthquakes if an unreliable bracing system is used.A welldesigned and detailed concentric bracing system is neededfor steel buildings in a seismically active area.Failure of a concentric bracing member occurs at the mid-length plastic hinge.A refined finite element model has been developed to simulate the hysteresis behavior of bracing members under cyclic loading including fracture.The model provides similar hysteresis behavior to previous(Shaback and Brown [1])and two new experiments(Tremblay et al.[2]).The specimens were subjected to different loading protocols.It was found that an initial imperfection affects the pre-buckling and first buckling cycles but has no effect on the following cycles.The greater the initial yield stress of the HSS,the earlier is the occurrence of local buckling.The cumulative plastic strain is greater at the outer surface than at the inner surface of the compressive corners/web of the mid-length plastic hinge where fracture initiates.Significant local rotation follows the same trend as the significant plastic strain of the same element where fracture initiates.
Steel buildings are susceptible to damage during earthquakes if an unreliable bracing system is used.A welldesigned and detailed concentric bracing system is neededfor steel buildings in a seismically active area.Failure of a concentric bracing member occurs at the mid-length plastic hinge.A refined finite element model has been developed to simulate the hysteresis behavior of bracing members under cyclic loading including fracture.The model provides similar hysteresis behavior to previous(Shaback and Brown [1])and two new experiments(Tremblay et al.[2]).The specimens were subjected to different loading protocols.It was found that an initial imperfection affects the pre-buckling and first buckling cycles but has no effect on the following cycles.The greater the initial yield stress of the HSS,the earlier is the occurrence of local buckling.The cumulative plastic strain is greater at the outer surface than at the inner surface of the compressive corners/web of the mid-length plastic hinge where fracture initiates.Significant local rotation follows the same trend as the significant plastic strain of the same element where fracture initiates.
引文
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