Analysis of multiple wavelengths of Lamb waves generated by meander-line coil EMATs.
The electromagnetic acoustic transducers (EMATs) with a meander-line coil possess the capability of generating Lamb waves carrying multiple wavelengths, and the characteristics of multiple wavelengths is analyzed by developing a spatial transversal filter model for the EMAT. It is shown that the characteristics is due to the wavelength spectrum of the EMATs, which is a wavelength-domain representation of information about the wavelength components, and the magnitude of each components is modulated by an envelope which depends on the geometric pattern of the meander-line coil. The characteristics of multiple wavelengths might cause the multi-modes phenomenon, therefore a method for removing the effect of multiple wavelengths is proposed. It is shown that the effect can be removed by designing an EMAT which can produce a special envelop to suppress the harmonic wavelengths. Experiments are set up to study the characteristics of multiple wavelengths and verify the validity of the proposed method.
School of Electrical Engineering and Automation, Harbin Institute of Technology, Harbin 150001, China.
Guofu
G
Zhai
Tao
T
Jiang
Lei
L
Kang
D000162:Acoustics / Q000295:instrumentation*; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008280:Magnetics / Q000295:instrumentation*; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D008962:Models, Theoretical; D012542:Scattering, Radiation; D013016:Sound; D014159:Transducers
Electromagnetic acoustic transducers; Lamb waves; Meander-line coil; Multiple wavelengths excitation