A study on propagation characteristics of vibration waves in a mass eccentric Timoshenko beam when encounter discontinuities

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Journal of Vibration and Shock ›› 2022, Vol. 41 ›› Issue (20) : 37-45.

WANG Jian1,2，YUAN Xiufeng1，HU Yongbiao2

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Abstract

In engineering practice or considering low-frequency vibrations of ships, submarines, etc., sometimes the center of mass and the centroid do not coincide in the corresponding beam model, whereas this mass eccentricity will cause bending-longitudinal coupling effects. Concentrating on flexural propagation waves, flexural attenuation waves and longitudinal waves, the transmission and reflection matrices of these waves at the elastic support, change in cross-section, boundary and right-angle corners of the Timoshenko eccentric beam were derived, and the coupling and transition of waves were discussed in this paper. The results show that enhancement of eccentricity facilitates the transition from flexural attenuation waves to propagation ones. If the frequency or eccentricity is increased, or both, the contribution to longitudinal waves attributes to flexural waves will become greater. The coupling effects will not arise between the three types of waves at boundary. When there exists an abrupt variation of cross-section at the location where waves emit, the transition of flexural attenuation waves to propagation ones occurs at the cut-off frequency corresponding to the geometric size of this new cross-section.
Key words: wave transition; mass eccentricity; Timoshenko beam; bending-longitudinal coupling

Key words

wave transition / mass eccentricity / Timoshenko beam / bending-longitudinal coupling

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WANG Jian1,2，YUAN Xiufeng1，HU Yongbiao2. A study on propagation characteristics of vibration waves in a mass eccentric Timoshenko beam when encounter discontinuities[J]. Journal of Vibration and Shock, 2022, 41(20): 37-45

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