342 2 0 1 2 3 Journal of Shenyang University of Technology Vo l 34 No 2 Mar 2 0 1 2 1000-1646 2012 02-0192 - 06 110870 ANSYS TB 552 A Three-dimensional finite element analysis on radiation sound field of electromagnetic ultrasonic surface wave GAO Song-wei ZHOU Jia-wei YANG Li-jian XING Yan-hao School of Information Science and Engineering Shenyang University of Technology Shenyang 110870 China Abstract In order to obtain the distribution of radiation acoustic field generated at both surface and inner of measured specimen for electromagnetic ultrasonic surface wave transducer ANSYS finite element simulation softw are w as applied to simulate the radiation sound field of electromagnetic ultrasonic transducer The three-dimensional 3D finite element model for electromagnetic ultrasonic transducer was established and the optimization w as performed And a quantitative relationship betw een the induced eddy current in the measured specimen and stimulating coil parameters of the transducer w as derived With the electromagnetic structural coupling method the displacement variation of particles w ith different orientations at both surface and inner of measured specimen w as obtained The distribution of radiation sound field generated inside the measured specimen was analyzed and the directionality rule of radiation sound field generated at the surface of measured specimen was given In addition an electromagnetic ultrasonic defect detection platform was established according to the simulation model The experimental results are basically consistent w ith the simulated results for the direction angle The results show that the finite element simulation on the radiation sound field of electromagnetic ultrasonic surface wave can provide the basis for the optimization of design determination of practical defect detecting range arrangement position of receiving coil as well as installation angle of sending and receiving devices wwwcameoorg Key words electromagnetic ultrasonic transducer ultrasonic surface wave finite element radiation sound field directivity stimulating coil Lorentz force eddy density 2010-12 - 09 60927004 1956 -
2 193 EMAT F a λ 1 a λ 1 /2 EMAT 8 9 EMAT H = J C 1 B = μh 2 2-3 EMAT E = - B 3 t J = γe 4 4-6 F = J B + B S 5 H J C B μ EMAT E EMAT EMAT γ J ANSYS B S F 5 F J B S B 1 EMAT 2 EMAT 2 1 EMAT EMAT 3 EMAT 4 7 EMAT 2 1 wwwcameoorg 2 EMAT Fig 2 3D physical model for EMAT 1 Fig 1 Principle diagram of energy transduction for electromagnetic ultrasonic surface wave 64 mm 60 mm 50 mm 880 ka/m J C 300 mm 300 mm 20 mm B J E 1 1 10-7 Ω /m
194 34 30 mm 0 5 mm 0 5 mm 8 0 1 mm 8 100 A 500 khz EMAT v J EMAT 2 950 m /s λ f f λ = v 6 λ 6 mm h 3 J 4 a λ EMAT a 3 0 mm EMAT 3 ~ 5 1 m 1 m 0 3 m 3 EMAT 3 Fig 3 EMAT 3D finite element model for EMAT without air field SOLID97 1 30 1 0 0 5 370 A x A y A z 2 CURR 3 40 50 1 0 1 0 0 5 0 5 361 353 4 60 1 0 0 5 348 5 30 0 5 0 5 373 6 30 1 5 0 5 369 7 30 2 0 0 5 367 2 2 EMAT 8 30 0 5 0 2 374 9 30 0 5 1 0 370 10 30 0 5 1 5 367 7 2 GPa 0 5 2 7 10 3 kg m - 3 l d h SOLID45 3 U x U y U z 1 5 J wwwcameoorg 3 EMAT l d EMAT d = 0 5 mm h = 0 2 mm EMAT EMAT 5 J Fig 4 4 EMAT 3D physical model for EMAT EMAT 3 l 30 ~ 60 mm d 0 5 ~ 2 0 mm h 0 2 ~ 1 5 mm J 3 1 Tab 1 1 EMAT Optimization test sheet for EMAT coil l /mm d /mm h /mm J / 10-6 A m - 2 5 l l = 30 mm
2 195 Fig 5 Change of eddy current density J with various factors of stimulating coil for measured specimens 4 EMAT 4 1 EMAT 7 8 ANSYS A 11 A 12 A 13 S T S A 21 A 22 A 23 B = T B A 31 A 32 A I T 33 I 7 S B I A ij S B I T S T B T I 7 x U x Fig 7 X-axis displacement U x curve of node 7 on surface of measured specimens A 11 0 0 S T珘 S 0 A 22 0 B = T珘 B 8 0 0 A I T珘 33 8 { A 11 S B I S = T珘 S S B I A 22 S B I B = T珘 B S B I 9 A 33 S B I I = T珘 I S B I I wwwcameoorg 9ANSYS 8 z U z Fig 8 Z-axis displacement U z curve of node on surface of measured specimens 7 8 U x 4 2 EMAT U z EMAT U x U z USUM 6 x 6 x x z x 6 USUM Fig 6 USUM distribution of total displacement of node for measured specimens EMAT EMAT x z U x U z
196 34 U y 4 3 1 9 U y 20 mm U x U y U z 3 2 127 10-10 m 1 232 10-9 m 6 440 10-11 m U y U x U z 6 mm 120 mm θ 0 ~ 12 20% EMAT lamb SV θ 10 λ l sin θ = λ /l 10 9 y U y lamb SV Fig 9 Y-axis displacement U y curve of node EMAT on surface of measured specimens 30 mm 6 mm 10 θ 11 5 4 3 2 11 20 mm 6 mm 30 5 mm 120 mm 12 4 3 EMAT EMAT EMAT EMAT 10 wwwcameoorg 10 Fig 10 11 Fig 11 EMAT Schematic distribution of radiation sound field of EMAT surface wave EMAT Test device for EMAT EMAT 12
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