Analysis of a Nondestructive Evaluation Technique for Defect Characterization in Magnetic Materials Using Local Magnetic Measurements

Table 4

Results of the inverse problem for the measured data from Table 1, obtained from a sample with air gap at $\alpha =-0.001$ m and $\beta =0.010$ m. The results are similar for both methods. We obtain a very good prediction of the position of the air gap for the larger currents.

	Small perturbations			Sensitivity
$I_{\text{set}}$ (A)	${\alpha }_{\min \hspace{0.17em}}$ (m)	${\beta }_{\min \hspace{0.17em}}$ (m)	$F_{\min \hspace{0.17em}}$	${\alpha }_{\min \hspace{0.17em}}$ (m)	${\beta }_{\min \hspace{0.17em}}$ (m)	$F_{\min \hspace{0.17em}}$
3.0	0.000488	0.012293	1.24e-05	0.000522	0.012589	1.24e-05
2.5	0.001140	0.008886	1.26e-05	0.001217	0.008791	1.20e-05
2.0	0.000651	0.009374	2.38e-05	0.000739	0.009179	2.37e-05
1.5	0.000024	0.010203	4.42e-05	0.000153	0.009758	4.42e-05
1.0	0.001689	0.006316	8.37e-05	0.001623	0.006228	8.37e-05
0.5	0.006739	0.002781	2.81e-04	0.005553	0.002319	2.80e-04