判定延性材料断裂行为和裂尖约束的无因次参量R  

AN NON DIMENSIONAL PARAMETER R FOR ESTIMATING FRACTURE BEHAVIOUR OF DUCTILE MATERIAL AND CONSTRAINT OF CRACK TIP

作　　者：刘元镛[1] 孙洪涛[1] 

机构地区：[1]西北工业大学飞机工程系

出　　处：《机械强度》1998年第3期171-174,共4页Journal of Mechanical Strength

基　　金：国家教委博士点基金

摘　　要：从应变能密度概念出发，运用无因次参量Ｒ讨论了裂尖附近处元素的三轴应力状态和裂尖约束程度。利用参量Ｒ估计了大尺寸三点弯曲试样在不同裂纹长度下的断裂行为，根据Ｒ的大小可以判定具有较好延性的材料是属于剪切断裂还是解理断裂，利用无因次参量Ｒ对判定延性材料的断裂行为和裂尖约束程度具有普遍意义。本文提出的方法简单、实用，在工程上有使用价值。Based on the concept of strain energy density,the triaxial stress state and constraint of the elements of the crack near by tip are discussed by using the nondimensional parameter R .The R is directly proportional to σ 2 e/ σ 2 m,and also is a function of the Poisson's ratio ν .In the paper,the fracture behaviour of three point bend specimen with different crack length is evaluated by R ,and an estimation is given for ductile material how to transform from shear fracture to cleavage fracture.It has universal meaning for ductile material to estimate the fracture behaviour and constraint of the crack tip using the parameter R .The method in the paper is simple and valuable in the engineering project.

关 键 词：断裂行为 解理断裂 应变能密度 延性材料 

分 类 号：O346.1[理学—固体力学]