Analysis of multiple wavelengths of Lamb waves generated by meander-line coil EMATs

作者：Zhai Guofu; Jiang Tao^*; Kang Lei

来源：Ultrasonics, 2014, 54(2): 632-636.

DOI：10.1016/j.ultras.2013.09.003

• Electromagnetic acoustic transducers
• Multiple wavelengths excitation
• Lamb waves
• Meander-line coil

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.

• 出版日期2014-2
• 单位哈尔滨工业大学