摘要
利用ANSYS有限元模拟软件,结合力磁耦合关系,分别模拟三种放置方式下,试件沿轴转动时初始状态和屈服后的法向和切向磁信号。对比得出以下结论:首先,当地磁场与试件加载方向不平行或与检测面出现夹角时,法向磁信号相比切向磁信号更为准确.地磁场方向对屈服后试件的影响要比初始状态大,尤其在缺陷附近应力集中区域。其次,当试件不是正南正北放置,而是东西放置或者与地磁场存在一定夹角时,按原来方向的法向和切向信号判断试件应力集中将不再准确,因此找到此时磁场方向下试件表面的法向和切向磁信号是做出准确检测的前提条件。另外,当大地磁场完全垂直于试件表面时,无论切向还是法向磁信号都基本为一直线,只有在缺陷处有些许变化,原来过零点和极大值的现象都不再出现。所以在实际工程中,要尽可能避免试件检测面与大地磁场完全垂直,否则以法向信号过零点和切向信号极大值为依据的经验判断方法将不再适用。
The normal and tangential magnetic signals of the specimen at initial state and yield state have been simulated by using ANSYS finite element simulation software,combining with the relationship of magneto-mechanical coupling when placed at three ways as well as rotating along the axis.The conclusions are as follows by comparison.Firstly,when the geomagnetic field hasn t paralleled with the loading direction of specimen or has included angles with inspection face,normal magnetic signals are more accurate compared with tangential magnetic signals.The influence of geomagnetic field direction on specimen at yield state is bigger than that at initial state,especially at the stress concentration zone of defects.Secondly,when the specimen isn t placed in a south-north direction,whereas in a east-west direction it has included angles with the geomagnetic field,the normal and tangential magnetic signals of original direction cannot be used to judge the stress concentration of specimen accurately,so the precondition of accurate testing is finding the normal and tangential magnetic signals of the specimen at this direction of magnetic field.Finally,when the geomagnetic field is absolutely perpendicular to the surface of specimen,whether the normal or tangential magnetic signal is basically a line,or it only changes in defects,so the original phenomenon like zero crossing point(ZCP)and maximum value don t appear.Therefore,it should be avoided that the testing face of specimen is absolutely perpendicular to geomagnetic field in practical engineering,otherwise the experience judgment way based on ZCP of normal magnetic signal and maximum value of tangential magnetic signal cannot be used.
作者
苏三庆
马小平
王威
杨熠奕
SU Sanqing;MA Xiaoping;WANG Wei;YANG Yiyi(School of Civil Engineering,Xi'an Univ,of Arch.&Tech.,Xi'an 710055,China)
出处
《西安建筑科技大学学报(自然科学版)》
北大核心
2019年第4期463-470,共8页
Journal of Xi'an University of Architecture & Technology(Natural Science Edition)
基金
国家自然科学基金项目(51878548,51578449)
陕西省自然科学基础研究计划重点基金(2018JZ5013)
陕西省教育厅省级重点实验室科研计划项目(14JS044)
关键词
金属磁记忆检测
大地磁场
法向磁信号
切向磁信号
力-磁耦合
metal magnetic memory testing(MMMT)
geomagnetic field
normal magnetic signals
tangential mag netic signals
magneto-mechanical coupling