基于CTOD特征值的桥梁钢防脆断评价方法研究  

Research on Methods to Evaluate Brittle Fracture Resistance of Bridge Steel Based on CTOD Characteristic Value

作　　者：鞠晓臣 赵欣欣 张佳丹 彭洋[2] 左照坤 JU Xiao-chen;ZHAO Xin-xin;ZHANG Jia-dan;PENG Yang;ZUO Zhao-kun(Railway Engineering Research Institute,China Academy of Railway Sciences Co.,Ltd.,Beijing 100081,China;Nanjing Tech University,Nanjing 211816,China)

机构地区：[1]中国铁道科学研究院集团有限公司铁道建筑研究所,北京100081 [2]南京工业大学,江苏南京211816

出　　处：《桥梁建设》2022年第2期47-52,共6页Bridge Construction

基　　金：国家自然科学基金高铁联合基金资助项目(U193420108);中国国家铁路集团有限公司科技研究开发计划课题(P2019G002);中国铁道科学研究院集团有限公司国家创新平台开放基金项目(2020YJ088)。

摘　　要：为保证铁路钢桥中高强度桥梁钢在低温环境下的服役安全,提出基于裂纹尖端张开位移(CTOD)特征值的桥梁钢防脆断评价方法。首先建立基于CTOD的桥梁钢脆性断裂判据,再基于断裂力学理论推导典型桥梁钢构件断裂驱动力理论公式,依据断裂韧性CTOD特征值随温度和厚度的变化规律提出断裂抗力经验公式。以Q690qE桥梁钢为例,基于以上方法,分析钢构件工作应力水平以及裂纹尺寸得到断裂驱动力,通过回归Q690qE桥梁钢的CTOD试验数据得到断裂抗力,将断裂驱动力和断裂抗力代入脆性断裂判据,得到了Q690qE桥梁钢在不同温度下的容许厚度。In this paper,a method to evaluate the brittle fracture resistance of bridge steel that is based on the characteristic value of crack tip opening displacement(CTOD)is proposed,which can be referenced to evaluate the service safety of high-strength steel of steel railway bridge.First,the brittle fracture resistance criteria for bridge steel based on CTOD are developed.Then,the theoretical formula of fracture driving forces of the typical bridge components is derived on the basis of the theories of fracture mechanics.At last,the empirical formula of fracture resistance is put forward,taking into account the variation of characteristic value of fracture toughness CTOD along with variation of temperature and plate thickness.Taking the Q690qE steel as an example,the method is applied to analyze the stress level and crack dimension of the in-service steel components to obtain the fracture driving force,the CTOD test results of the fracture resistance of the Q690qE steel is regressed to gain the fracture resistance,and the fracture driving force and resistance are substituted into the formula to identify the brittle fracture,upon which,the allowable thicknesses of Q690qE steel suitable to different temperatures are gained.

关 键 词：铁路桥 钢桥 高性能桥梁钢 防脆断评价 裂纹尖端张开位移 容许厚度 断裂力学 

分 类 号：U448.13[建筑科学—桥梁与隧道工程] U441.6[交通运输工程—道路与铁道工程]