TY - JOUR
T1 - Analysis of eddy currents in a bar containing an embedded defect
AU - Liaw, J. W.
AU - Chu, S. L.
AU - Yeh, C. S.
AU - Kuo, M. K.
PY - 1999/7
Y1 - 1999/7
N2 - The eddy current distribution is studied in a metal bar containing an embedded defect inserted within an encircling coil. Furthermore, the impedance change of the coil regarding the characteristics of the defect is determined. The defects investigated are nonmetallic inclusions and embedded cracks which may occur during the manufacturing processes of bars. To simulate these problems, a two-dimensional transverse-electric model is proposed, and then a set of coupled surface integral equations are formulated systematically. Since the magnetic field is unknown along the boundary of the defect, an additional boundary condition derived from Maxwell's equations is used. Using the boundary element method (BEM), these integral equations are solved in terms of nodal unknown-current density. After the current distribution is obtained, the impedance changes of the coil caused by the defects are calculated vs. the configuration of defect for various frequencies. If the inclusion is circular and located at the center of the bar, good agreements are found by comparing the BEM solutions with the analytical ones. An auxiliary surface integral equation is also derived to further determine the currents on both sides of the crack.
AB - The eddy current distribution is studied in a metal bar containing an embedded defect inserted within an encircling coil. Furthermore, the impedance change of the coil regarding the characteristics of the defect is determined. The defects investigated are nonmetallic inclusions and embedded cracks which may occur during the manufacturing processes of bars. To simulate these problems, a two-dimensional transverse-electric model is proposed, and then a set of coupled surface integral equations are formulated systematically. Since the magnetic field is unknown along the boundary of the defect, an additional boundary condition derived from Maxwell's equations is used. Using the boundary element method (BEM), these integral equations are solved in terms of nodal unknown-current density. After the current distribution is obtained, the impedance changes of the coil caused by the defects are calculated vs. the configuration of defect for various frequencies. If the inclusion is circular and located at the center of the bar, good agreements are found by comparing the BEM solutions with the analytical ones. An auxiliary surface integral equation is also derived to further determine the currents on both sides of the crack.
UR - https://www.scopus.com/pages/publications/0032681249
U2 - 10.1016/S0963-8695(98)00051-6
DO - 10.1016/S0963-8695(98)00051-6
M3 - 文章
AN - SCOPUS:0032681249
SN - 0963-8695
VL - 32
SP - 293
EP - 303
JO - NDT and E International
JF - NDT and E International
IS - 5
ER -
