Lorentz force evaluation: A new approximation method for defect reconstruction
Lorentz force evaluation: A new approximation method for defect reconstruction
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DOI：
10.1016/j.ndteint.2013.05.005
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发表时间：
2013-10-01
影响因子：
4.2
通讯作者：
Ziolkowski, M.
中科院分区：
文献类型：
--
作者：
Petkovic, B.;Haueisen, J.;Ziolkowski, M.
我们提出了一种新的非接触、无损评估移动层合导体的方法，即洛伦兹力评估（LFE）。测量了施加在相对于试样运动的永磁体上的洛伦兹力（LF）。我们提出了一种基于三维有限体积离散化试样和缺陷区域局部电流分布近似缺陷的新颖快速向前计算方法。将近似解与平行六面体次表面缺陷的详细有限元模型解进行了比较。我们得到的LF差异范围在1.7%到6.7%之间，表明我们的近似方法产生了足够的性能。在此基础上，提出了一种基于新颖正演方法的线性逆解。我们将从位于层压导电棒内的尺寸为2mm x 2mm x 12mm的地下缺陷中测量的实验数据进行了反演。重建方法得到了缺陷的正确位置，每个方向的精度为1mm。重构结果与相同裂纹形态的高分辨率有限元分析结果进行了比较。我们得到了正确的裂缝横向位置，尽管深度估计显示出轻微的偏差。(C) 2013 Elsevier Ltd.版权所有。
We propose a new method for contactless, nondestructive evaluation of moving laminated conductors, the so-called Lorentz force evaluation (LFE). The Lorentz force (LF) exerting on a permanent magnet moving relative to the specimen is measured. We propose a novel fast forward calculation of the LF based on a three-dimensional finite volume discretization of the specimen and an approximation of defects using local current distributions in the defect region. The approximate solution is compared with solutions from detailed finite element models developed for parallelepipedic subsurface defects. We obtain differences in LF that range between 1.7% and 6.7%, indicating that our approximation method yields sufficient performance. Furthermore, a linear inverse solution based on the novel forward method is presented. We invert the experimental data measured from a subsurface flaw with the dimensions of 2 mm x 2 mm x 12 mm located within a laminated conductive bar. The reconstruction method yields the correct position of the flaw with an accuracy of 1 mm in each direction. The reconstruction results are compared with high-resolution finite element analysis of the same crack configuration. We obtain correct lateral positions of the cracks, although the depth estimation shows a slight bias. (C) 2013 Elsevier Ltd. All rights reserved.