基于微观断裂机制外加劲肋X型圆钢管相贯节点承载力研究  

Research on Bearing Capacity of CHS X-joints of Externally Stiffeners Based on Microscopic Fracture Mechanism

作　　者：阳勇 黄政华[1] 何响 YANG Yong;HUANG Zhenghua;HE Xiang(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：《贵州大学学报（自然科学版）》2023年第4期90-98,共9页Journal of Guizhou University:Natural Sciences

基　　金：国家自然科学基金资助项目(51368009);贵州省科技计划资助项目(黔科合基础[2018]1036)。

摘　　要：为了研究外加劲肋X型圆钢管相贯节点的断裂行为,对本文设计的30个模型进行有限元分析,运用空穴扩张模型(void growth model,VGM)对节点进行断裂预测。分析加劲肋几何参数和支主管外径比对外加劲肋X型圆钢管相贯节点承载力的影响。运用VUSDFLD子程序分析节点断裂区域子模型开裂到完全断裂这一过程承载力的变化情况和裂纹扩展过程。结果表明:外加劲肋长度的增加会提高节点的承载能力,外加劲肋的厚度对节点的承载力影响不大。支主管外径比的改变会改变节点的破坏模式,随着支主管外径比的增加,节点刚度提高,节点的断裂出现在节点极限变形之前,外加劲肋对节点承载能力的提高效果会先增加后减小,当支主管外径比很大时,采用加劲肋加固的效果不再那么明显。无论是否设置外加劲肋,节点焊缝在开裂后,节点不会立即失去承载能力,节点从开裂到完全断裂过程中承载力会有所提高,随着相贯节点焊缝焊脚尺寸的增加,节点的承载能力逐渐提高,节点从开裂时刻到断裂时刻承载力提高的比率会逐渐增加。In order to study the fracture behavior of the circular hollow section(CHS)X-joints of externally stiffeners,the finite element analysis of the 30 models designed in this paper was carried out,and the void growth model(VGM)was used to predict the fracture of the joints.The influence of the geometric parameters of the stiffener and the ratio of the outer diameter of the branch to the main pipe is analyzed.The VUSDFLD subprogram is used to analyze the change of the bearing capacity and the crack propagation process from the cracking to the complete fracture of the submodel of the node fracture area.The results show that the increase of the length of the external stiffener will improve the bearing capacity of the joint,and the thickness of the external stiffener has little effect on the bearing capacity of the joint.The change of the outer diameter ratio of the branch pipe will change the failure mode of the joint;with the increase of the outer diameter ratio of the branch pipe,the stiffness of the joint increases,and the fracture of the joint occurs before the ultimate deformation of the joint.After the increasing,it decreases.When the ratio of the outer diameter of the branch to the main pipe is very large,the effect of stiffener reinforcement is not so obvious.No matter whether external stiffeners are installed or not,after the joint weld is cracked,the joint will not lose its bearing capacity immediately,and the bearing capacity of the joint will increase during the process from cracking to complete fracture.The bearing capacity of the node gradually increases,and the ratio of the bearing capacity improvement of the node from the moment of cracking to the moment of fracture will gradually increase.

关 键 词：加劲肋 相贯节点 子程序 断裂 裂纹扩展 

分 类 号：TU392.3[建筑科学—结构工程]