铁磁试件缺口种类对磁记忆信号的影响研究  

Study on the influence of notch type of ferromagnetic specimen on magnetic memory signal

作　　者：王大鸾 任尚坤[1] 邓可郁 袁润冲 WANG Daluan;REN Shangkun;DENG Keyu;YUAN Runchong(Key Laboratory of Nondestructive Testing of Ministry of Education,Nanchang Hangkong University,Nanchang 330063,China)

机构地区：[1]南昌航空大学无损检测技术教育部重点实验室,江西南昌330063

出　　处：《中国测试》2023年第9期1-6,共6页China Measurement & Test

基　　金：国家自然科学基金(51865039)。

摘　　要：为研究铁磁试件不同缺口对磁记忆信号的影响,利用ANSYS有限元仿真软件,结合力磁耦合模型,在拉应力和地磁场的共同作用下对3种不同缺口的20#钢板进行仿真,分别提取磁记忆信号切向分量和法向分量。仿真结果表明:在地磁场作用下,随着拉应力的增大,3种试件在各自缺口处均出现应力集中现象,在拉应力大于120 MPa后应力集中现象愈发明显。受到同样大小的拉应力时,V形缺口试件倾向于裂纹的扩展,而U形缺口试件倾向于裂纹的形成,U形缺口的应力集中范围更大,因此双关联缺口试件在U形缺口处更易断裂。双关联缺口试件磁记忆信号法向分量约为检测路径上两个缺口处磁记忆信号值的叠加之和,故试件被近似磁化成一个磁铁。双关联缺口试件检测路径中间点的磁记忆信号切向分量并没有极值,因此用其判断双关联缺口试件的应力集中区不再适用。缺口试件在弹性阶段,磁记忆信号随拉应力变化幅度较小;缺口试件在塑性阶段,磁记忆信号值随拉应力变化幅度较大。因此可以利用试件弹、塑性阶段磁记忆信号变化,对工程试件的缺陷损伤进行早期识别。In order to study the influence of different notches on magnetic memory signal of ferromagnetic specimen,ANSYS finite element simulation software was used to simulate the 20#steel plate with three different notches under the joint action of tensile stress and geomagnetic field,and the tangential component and normal component of magnetic memory signal were extracted respectively.The simulation results show that:under the action of geomagnetic field,with the increase of tensile stress,the stress concentration phenomenon occurs in the three specimens at their respective openings,and becomes more obvious when the tensile stress is greater than 120 MPa.When subjected to the same amount of tensile stress,V-notch specimens tend to crack propagation,while U-notch specimens tend to crack formation.The stress concentration range of U-notch is larger,so the double-correlated notch specimens are more likely to fracture at the U-notch.The normal component of the magnetic memory signal of the double-correlated notch specimen is about the sum of the superposition of the magnetic memory signal values of the two holes on the detection path,so the specimen is magnetized into a magnet approximately.There is no extreme value of tangential component of magnetic memory signal at the middle point of the test path of double-correlated notch,so it is no longer applicable to judge the stress concentration area of double-correlated notch.At the elastic stage,the magnetic memory signal varies slightly with tensile stress.In the plastic stage,the magnetic memory signal value varies greatly with tensile stress.Therefore,the defect damage of engineering specimens can be identified early by using magnetic memory signal changes in elastic and plastic stages.

关 键 词：无损检测 不同缺口试件 ANSYS有限元仿真 磁记忆信号 

分 类 号：TG115.284[金属学及工艺—物理冶金]