Q460钢基于微观机制的延性断裂判据研究

Study on micro mechanism-based ductile fracture criteria for Q460 steel

基于微观机制的断裂模型可用来预测钢结构的延性断裂.为校准Q460钢的微观断裂模型参数,进行了材料试验和对应的有限元分析,以及断口的扫描电镜试验.试件由Q460钢板焊接节点抽取的母材和熔敷金属圆棒制作而成.用自编的VUMAT子程序,分别以校准的应力修正临界应变模型(SMCS)和空穴扩张模型(VGM)为断裂判据,分析了18个圆周平滑槽口单向拉伸试件的开裂全过程,得到了裂后荷载位移曲线,其与试验结果吻合较好,验证了SMCS和VGM模型用于节点裂后路径分析的可行性.

Micromechanical facture models can be used to predict ductile fracture in steel structures. In order to calibrate theparameters in the micromechanical models for Q460 steel, material tests, their corresponding finite element analyses, and scanningelectron microscope tests were conducted. The test specimens were made from round bars of base metal and deposit metal extractedfrom welded connections of Q460 steel plates. The VUMAT subroutine edited by the author was employed. Taking the calibratedstress modified critical strain (SMCS) model and void growth model (VGM) as fracture criteria, the whole cracking processes ofeighteen circumferentially smooth-notched tensile specimens were simulated, the post-fracture load displacement curves wereobtained, which are close to the test results. The results verify the feasibility of using SMCS and VGM models in the post fracturepath analysis of connections.