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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.
A method to study the pulse eddy current response of the test piece by direct analysis of transient eddy currents and induced magnetic fields is proposed. Based on the experimental verification, the pulse eddy current response of a finite thickness ferromagnetic test piece is obtained by numerical simulation. The eddy current diffusion law and the pulse eddy current response were divided into two stages before and after. The response curves of different resistivity and permeability model at the same time and the curves of the induced voltage with time were fitted. The induced voltage and Resistivity, permeability and time.The results show that the pre-pulse induced voltage is attenuated by 0.5 power of resistivity and 0.5 power of permeability, and attenuated by 1.5 power of time. The voltage decays according to the law of negative exponential with time. The exponential decay coefficient is proportional to the resistivity of the specimen and inversely proportional to the permeability.