中文摘要：

对于含缺陷材料结构的强度,以裂纹为主要特征的断裂力学是其力学行为分析的有效途径,裂纹扩展过程区能被简化成具有黏聚力的裂纹段。为探讨带切口的铸铁裂纹发展规律及黏聚裂纹张开位移与黏聚应力的本构关系,对8种不同切口尺寸的铸铁梁进行三点弯曲加载实验,通过应变计电测跟踪测试,得到预制裂纹端部的张开位移随载荷变化曲线。由确定黏聚裂纹张开位移与黏聚应力分布的解析方法,计算得到该材料黏聚裂纹张开位移及与应力的本构关系。计算预制裂纹尖端张开位移与应变计测试结果基本符合。

英文摘要：

As for structure strength with fault material,fracture mechanics with main character of crack is an effective way in mechanical behavior analysis,the crack extended progress zone can be simplified for a crack segment with cohesive stress.In order to investigate the crack growth law and the constitutive relationship between crack opening displacement（COD） and cohesive stress in notched cast iron,the three-point bending experiments of 8 sized notched specimens were carried out,in which all specimens were measured with electrical strain gauges.Then the curves of COD with load were obtained in the crack growth zone.Using analytical method of cohesive crack model,the opening displacement and cohesive stress distribution,and the constitutive relationship between cohesive stress and COD were obtained.The calculated CODs of pre-crack top are in appropriate with tested results.