| Biography | |
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 Prof. Peter W. TSE City University of Hong Kong, Hong Kong., China |
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| Title: American Society of Mechanical Engineers | |
| Abstract:
This paper addresses the studies carried out on an I-beam to reveal the wave propagation characteristics and tackle the multi-mode propagation of Lamb waves. In general, the excitation and reception of the waves in the specimen can be facilitated using contact and non-contact methods. However, in the contact based methods the sensors like the piezoelectric and magnetostrictive need be physically mounted and cannot be employed to structures with high temperature, limited access and inspection in a hazardous environment. The non-contact methods on the other hand, like the laser-based system is a new and attractive inspection technique because it can be used where contactable sensors cannot be integrated with the specimens. The experimental setup consisted of a new 3D Scanning Laser Doppler Vibrometer manufactured by Polytec (3D-SLDV) and was used to acquire high resolution time-space Lamb waves that were propagating in the I-beam. A high power and pulsed Nd:YAG laser was used to emit the required Lamb waves. The emission and sensing of the waves were carried out simultaneously. The wave propagation data was recorded by scanning the surface of the I-beam in a sequential manner. The 3D-SLDV measured the in-plane and out-of-plane velocities across a user-defined grid with sufficient resolutions in x and y directions. The measured data was used to construct the wave patterns that were propagating in the I-beams at different time instants. Furthermore, as the waves in an I-Beam propagate with multiple modes even at low frequency range, filtering was carried out in the frequency-wavenumber domain in order to decompose the modes. The experimental mode having maximum correlation with the theoretical mode is extracted and time domain waveforms for this mode are reconstructed. The reconstructed waveforms bear single mode and can be interpreted easily as compared to the original data. The results presented thereby confirm that the new 3D-SLDV possesses tremendous capability in revealing the wave propagation characteristics and its interaction with defect. The results could be the first time that the waves propagating in a real I-beam can be visually observed, whilst in the past, it can only be visualized through simulation. The capability of using such totally laser-based 3D inspection system to reveal the characteristics of Lamb wave and its interaction with defects are substantial.
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| Biography:
Ir Prof. Peter W. TSE is a Fellow of the American Society of Mechanical Engineers (美国机械工程学会院士) and a Foundation Fellow and a Board Director of the International Society of Engineering Asset Management. He obtained his B.Eng. and M.Sc. from Canada and his Ph.D. from United Kingdom. He is currently the Deputy Director of the Centre for Systems Informatics Engineering (CSIE), the Director of Croucher Optical Nondestructive Testing (CNDT) Laboratory and the Smart Engineering Asset Management Laboratory (SEAM) at the City University of Hong Kong. He has been classified by the Council of Canadian Academies as the author of top 1% most highly cited papers in the related research field worldwide for year 2106 again. He is also the O-Committee Member of several International Standards Organization (ISO)’s (国际标准化组织) Technical Committees (TC): TC108、TC135 and TC199 (技术委员会会员). As of today, he has published more than 350 articles in various journals and proceedings obtained research fund/industrial doantions over $102 million dollars. Currently, his research outcomes have been applied to over 30 local and international companies.
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