摘要
提出了通过直接分析瞬变涡流和感应磁场来研究被测试件脉冲涡流响应的方法.在实验验证的基础上,采用数值模拟的方法计算得到了有限厚铁磁性试件的脉冲涡流响应.研究了试件中涡流扩散规律并将脉冲涡流响应分为前后2个阶段,将相同时间点不同电阻率、磁导率模型的响应曲线及感应电压随时间变化的曲线进行拟合,得到了感应电压与电阻率、磁导率及时间的关系.结果表明:脉冲涡流前期感应电压按试件电阻率的0.5次幂、磁导率的0.5次幂进行衰减,按时间的1.5次幂进行衰减;后期感应电压随时间按照负指数规律衰减,指数衰减系数与试件电阻率成正比,与磁导率成反比.
Method for the pulsed eddy current （PEC） response to a specimen based on direct analysis of transient eddy currents and induced magnetic fields was presented. Based on the experimental verification, the PEC response to a ferromagnetic specimen of finite thickness was computed with numerical simulation method. The law of eddy current diffusion in specimen was studied, and thus the PEC response was divided into two stages. The relation between the response and resistivity or permeability of the specimen was obtained by fitting the response curves of different resistivity or permeability models at the same time points, and the relation between the response and time was obtained by fitting the response curves with time. The results show that early PEC response decays with 0.5 powers to the resistivity, 0.5 powers to the permeability, and 1.5 powers to the time. The latter response decays with negative exponent to time, and the exponential decay coefficient is proportional to the resistivity hut inversely proportional to the permeability.
出处
《华中科技大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2011年第6期91-95,共5页
Journal of Huazhong University of Science and Technology(Natural Science Edition)
基金
国家自然科学基金资助项目(51077059)
国家科技支撑计划资助项目(2006BAK02B02)
关键词
无损检测
脉冲涡流
涡流扩散
铁磁性试件
数值模拟
曲线拟合
nondestructive testing
pulsed eddy current
eddy current diffusion
ferromagnetic speci men
numerical simulation
curve fitting
