基于约束参数的断裂韧性转化研究  

Transformation of fracture toughness based on constraint parameters

作　　者：刘志伟[1,2] 刘聪 薛启超 LIU Zhiwei;LIU Cong;XUE Qichao(Nuclear Power Institute of China,Chengdu 610213,China;College of Aerospace and Civil Engineering,Harbin Engineering University,Harbin 150001,China)

机构地区：[1]中国核动力研究设计院,四川成都610213 [2]哈尔滨工程大学航天与建筑工程学院,黑龙江哈尔滨150001

出　　处：《应用科技》2021年第1期98-102,共5页Applied Science and Technology

基　　金：国家自然科学基金项目(51409056);黑龙江省自然科学基金项目(LH2020E070)。

摘　　要：为解决材料在不同约束条件下断裂韧性转换的问题,基于三点弯曲试验过程的有限元模拟,对铁素体钢材的典型材料(低合金高强钢材Q345B)的断裂韧性进行了研究。针对不同约束水平(裂纹的深或浅)的三点弯曲试样建立ABAQUS有限元数值仿真模型,计算获得裂纹尖端断裂韧性J积分值,结合J-A_2方法计算不同裂纹深度的三点弯曲试样的约束参数A_2,研究了弹塑性断裂力学考虑约束效应的断裂韧性转化问题。结果表明,随裂纹长度的增加,约束参数A_2值逐渐增大,深裂纹试样的裂纹尖端处于高约束情况,更容易失效。运用J-A_2方法对不同裂纹深度三点弯曲试样的断裂韧性值进行了转化,转化结果与模拟值吻合良好,误差均在8%以内,验证了J-A_2法在断裂韧性转化中的可行性。In order to solve the problem of fracture toughness transformation of materials under different constraint condition,based on the three-point bending test process’s finite element simulation,we studied the fracture toughness of typical ferritic steel Q345B—a kind of low alloy high strength steel.The ABAQUS finite element numerical simulation model was established for three-point bending specimens with different constraint levels(deep or low crack)to calculate the J-integral value of fracture toughness at the crack tip.The constraint parameter A2 of a three-point bending specimen with different crack depth was calculated by the J-A2 method.The fracture toughness transformation problem was studied,considering the constraint effect in elastoplastic fracture mechanics.The results show that with the increase of crack length,the value of constraint parameter A2 increases gradually,and the crack tip of the deep crack specimen is in the high constraint condition,which is more likely to fail.The fracture toughness values of three-point bending specimens with different crack depths are transformed by the J-A2 method.The transformation results are in good agreement with the simulated values,and the errors are all within 8%,verifying the feasibility of the J-A2 method in fracture toughness transformation.

关 键 词：断裂韧性 三点弯曲 数值模拟 铁素体钢材 J积分 J-A_2方法 断裂韧性转化 约束效应 

分 类 号：O39[理学—工程力学]