【摘要】 利用透射式动焦散线研究了冲击作用下梁柱节点的动态断裂特性。由焦散斑特征尺寸获得梁柱构件的动态裂纹起裂时间、应力强度因子、扩展速度和材料的断裂韧性。试验结果表明预置裂纹梁柱结构的裂纹尖端应力集中诱发裂纹扩展,梁端节点裂纹受到正应力和剪应力的共同作用,裂纹表现为复合型断裂,而柱端节点的开裂时间明显滞后于梁端节点裂纹开裂,为I型裂纹。研究工作对于梁柱构件的抗冲击性能评估具有科学研究意义和工程应用价值。更多还原

【Abstract】 Dynamic caustics method is introduced to study dynamic fracture behavior of a beam-column connection under impact.According to the shadow spot patterns around crack tip recorded while it propagates during the dynamic fracture process,the dynamic stress intensity factor,the crack growth velocity and the fracture toughness can be estimated to evaluate the fracture properties of the beam-column member.Dynamic stress singularities of the crack tip lead to propagation of prefabricated cracks.The results indicate the regularity of normal stress and shear stress of microcrack propagation at the beam connection is the mixed mode fracture.The mode of crack at the column connection is the mode-I fracture.The comprehensive analysis shows that the cracking time of crack at the column connection evidently behind that at the beam connection.These results can help to evaluate strength and predict service life for beam-column connections.更多还原