热镀锌钢板锌层表面浅裂纹扩展特性研究  

Propagation performance of shallow cracks on zinc layer of hot-dipped galvanized steel plate

作　　者：陈庭记 刘永生 陶欣 黄凤华[2] 张大长[2] CHEN Tingji;LIU Yongsheng;TAO Xin;HUANG Fenghua;ZHANG Dachang(Nanjing Electric Power Design&Research Institute Co.,Ltd.,Nanjing 210037,China;College of Civil Engineering,Nanjing Tech University,Nanjing 211816,China)

机构地区：[1]南京电力设计研究院有限公司,南京210037 [2]南京工业大学土木工程学院,南京211816

出　　处：《中国科技论文》2023年第12期1390-1396,共7页China Sciencepaper

基　　金：国网公司2022年南京电力设计研究院有限公司科学技术项目(SGTYHT/18-JS-206)。

摘　　要：为了研究锌层表面浅裂纹的扩展行为,在Q420热镀锌钢板锌层表面预制浅裂纹形成预裂试件,对预裂试件分别开展单轴拉伸和循环疲劳加载试验,采用扫描电子显微镜技术记录并分析浅裂纹的扩展特征;基于扩展有限元法对锌层表面浅裂纹扩展过程进行数值模拟,探讨浅裂纹尖端区域的应力强度因子,从断裂力学角度揭示锌层表面浅裂纹的扩展机理。结果表明:在静载、疲劳荷载作用下,当镀锌钢板未超过极限强度时,锌层表面浅裂纹均不会出现明显的扩展;在拉伸作用下,表面浅裂纹附近区域应力水平非常低,仅在裂纹尖端区域产生应力集中现象,且裂纹深处尖端的应力水平明显高于表面裂纹尖端;裂纹长度中心位置处的裂纹尖端应力强度因子最大,但均小于锌层的断裂韧性,说明锌层表面浅裂纹不会在长度或深度方向上发生扩展。To investigate the propagation behavior of shallow cracks on zinc layer,hot-dipped galvanized Q420 steel plates with shallow cracks were tested under uniaxial tension and cyclic fatigue loading,respectively.The crack propagation characteristics were recorded and analyzed by scanning electron microscope.The extended finite element analysis was further carried out to simulate the propagation of the shallow cracks on zinc layer,and the stress intensity factor at crack tips was investigated to revel the crack propagation mechanism from the perspective of fracture mechanics.The results reveal that,when the steel plate specimens do not reach the ultimate strength,the shallow cracks on zinc layer fail to propagate under both static and fatigue loads.The stress level close to the shallow crack is fairly low,the stress concentration occurs only near the crack tip region,and the stress level at the deep tip of crack is significantly higher than that at the surface tip.Furthermore,the stress intensity factor of the crack tip at the crack length center is the largest,but the value is actually smaller than the fracture toughness of zinc layer,indicating that the shallow cracks on the surface of the zinc layer do not propagate in the direction of length or depth.

关 键 词：热镀锌 表面浅裂纹 裂纹扩展行为 扩展有限元 应力强度因子 

分 类 号：TU513[建筑科学—建筑技术科学]