基于微观机制圆钢管X型相贯节点焊缝延性断裂预测及Lode角参数分析  

Forecast of weld ductility fracture and analysis of Lode angle parameters based on micro-mechanism of round steel pipe X-type tubular joint

作　　者：夏义舒 黄政华[1] 石小龙 XIA Yi-shu;HUANG Zheng-hua;SHI Xiao-long(School of Civil Engineering,Guizhou University,Guiyang 550025,China)

机构地区：[1]贵州大学土木工程学院,贵州贵阳550025

出　　处：《空间结构》2020年第4期75-82,共8页Spatial Structures

基　　金：贵州省科技计划项目(黔科合LH字[2017]7257,黔科合基础[2018]1036);贵州大学2017年度学术新苗培养及创新探索专项(黔科合平台人才[2017]5788)。

摘　　要：运用Abaqus软件对3个不同尺寸的圆钢管X型相贯节点在单调荷载作用下的断裂行为进行了分析和预测.采用国产Q345钢材校准的微观断裂判据空穴扩张模型(VGM)对相贯节点进行断裂预测.分析结果显示,断裂起于相贯线鞍点焊缝内侧与支管相交处,与试验观察到的结果相符.计算断裂处的Lode角参数,结果表明该模型断裂前应力状态为拉伸-剪切复合应力状态,且剪切应力较大.由于VGM模型中韧性参数η是基于轴对称拉伸试验测得,而文中断裂预测值均大于实验值,因此建议在VGM模型中考虑Lode角参数对预测结果的影响,提高该模型在相贯节点断裂预测中的适用性.Abaqus software is used to analyze and predict the fracture behavior of three circular steel tube X-type tubular joints with different sizes under monotonic load. The fracture prediction of the intersecting joint was carried out by using the microfracture criterion cavitation expansion model(VGM) calibrated by domestic Q345 steel. Results show that the fracture occurs at the intersection of the inside seam of the saddle point and the branch pipe, which is consistent with results observed in the test. In addition, the stress state of the model before fracture is tensile and shear composite stress, and the shear stress is large. Since the toughness parameter in the VGM model is measured based on axisymmetric tensile test, the predicted value of fracture in this paper is greater than the experimental value. Therefore, it is suggested that the influence of Lode angle parameters on the prediction results should be considered in the VGM model to improve the applicability of the model in the fracture prediction of intersecting nodes.

关 键 词：相贯节点 极限承载力 微观断裂判据 Lode角 钢结构设计标准 

分 类 号：TU392.3[建筑科学—结构工程]