钢框架节点局部断裂冲击作用实验研究

对钢框架节点在强烈地震或极端荷载情况下因突然断裂引起的冲击作用进行了研究．讨论了断裂冲击值与断裂位置内力释放值的对应关系，通过单质点模型分析了冲击反应的量值范围，考察了冲击反应峰值与冲击作用时间和断裂发生后体系自振周期之比的关系．设计并实施了钢材单轴断裂和模型框架节点断裂两种实验，验证了采用具有高频采样能力的测试设备准确测取断裂过程中结构反应的可行性，揭示了节点瞬间断裂仍然包含渐进性和局部性两项特点．对节点瞬间断裂引起的冲击反应进行了初步的数值评估．

Tests on the Impact Effect of Partial Fracture at Steel Frame Connections

The paper presents a study of the impact effect of sudden fracture of steel frame connections due to severe earthquake or other extreme loads including a study of the relation of impulse caused by structural fracture to the release of inner force at the cracked location. The magnitude of the response to impact on the basis of the one, degree of freedom model, and the ratio of the peak value of response to natural period of system is investigated. Two types of fracture tests were designed and carried out both on uni-axial steel bar tensioned and moment resistant steel frame model. It is proved that by using device with the ability to collect testing data in high frequency the response during the fracture process can be measured quite well. It is also revealed that the instant fracture of structural connection is characterized by progressive and partial fracture. Numerical evaluation of the impact effect of connection fracture is carried out.