由裂纹尖端张开位移设计曲线确定X70钢裂纹长度临界值  

DETERMINATION OF X70 STEEL CRACK LENGTH CRITICAL VALUE BY CTOD DESIGN CURVE

作　　者：叶运勤[1] 苗张木[1] 孙洋洋[1] 

机构地区：[1]武汉理工大学交通学院,武汉430063

出　　处：《钢结构》2014年第2期24-27,47,共5页Steel Construction

摘　　要：裂纹长度临界值一直是结构安全性评估的重要指标,确定裂纹长度临界值的传统方法限于线弹性阶段且不适用于力学性能不均匀的焊接接头。在考虑焊接残余应力的情况下,使用有限元软件ANSYS计算出焊接残余应力的数值,依据英国BS 7448规范对X70钢断裂韧度裂纹尖端张开位移(CTOD)值进行测试,进而根据英国PD6493规范导出的CTOD设计曲线,对X70钢在ASME规范的设计应力下贯穿裂纹长度临界值进行确定。这种方法适用于弹塑性情况及力学性能不均匀的焊接接头。CTOD设计曲线在X70钢贯穿裂纹长度临界值中的应用科学严谨,兼顾了安全性与经济性,可供压力容器、管道生产和结构安全性评估时借鉴。The critical value of crack length is an important index of structural safety evaluation,the traditional method to determine the critical value of the crack length is limited to linear elastic stage and it is not applicable to the mechanical properties of non-uniform welded joints.Considering the welding residual stress condition,using the finite element software ANSYS the numerical welding residual stress was calculated;according to the BS 7448 specification,the fracture toughness CTOD values of X70 steel were tested,and then according to the CTOD design curve derived from PD 6493 specification,the critical value of crack length of X70 steel was determined under the design stress of ASME specification,This method is suitable for plastic and the welded joint whose mechanical properties are not uniform.The application of the CTOD design curve in determing the critical value of crack length of X70 steel is scientific and strict,it is both safety and economy and can be a reference for an enterprise which is engaged in production and structural safety assessment of pressure vessels and piping.

关 键 词：有限元 焊接残余应力 CTOD设计曲线 临界值 

分 类 号：TG407[金属学及工艺—焊接]