Dynamic behaviour of a rotating cracked beam

13th International Conference on Motion and Vibration Control; 12th International Conference on Recent Advances in Structural Dynamics

Yashar, Ahmed^1 ; Ghandchi-Tehrani, Maryam^1 ; Ferguson, Neil^1

Institute of Sound and Vibration Research, University of Southampton, Southampton

SO17 1BJ, United Kingdom^1

关键词: Dynamic behaviours;    Hamiltonian methods;    Modal assurance criterion;    Modal characteristics;    Rotating cantilever beams;    Slenderness ratios;    Three-dimensional designs;    Wind turbine blades;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/744/1/012057/pdf
DOI  :  10.1088/1742-6596/744/1/012057

来源: IOP

【 摘 要 】

This paper presents a new approach to investigate and analyse the vibrational behaviour of cracked rotating cantilever beams, which can for example represent helicopter or wind turbine blades. The analytical Hamiltonian method is used in modelling the rotating beam and two numerical methods, the Rayleigh-Ritz and FEM, are used to study the natural frequencies and the mode shapes of the intact rotating beams. Subsequently, a crack is introduced into the FE model and simulations are performed to identify the modal characteristics for an open cracked rotating beam. The effect of various parameters such as non-dimensional rotating speed, hub ratio and slenderness ratio are investigated for both the intact and the cracked rotating beam, and in both directions of chordwise and flapwise motion. The veering phenomena in the natural frequencies as a function of the rotational speed and the buckling speed are considered with respect to the slenderness ratio. In addition, the mode shapes obtained for the flapwise vibration are compared using the modal assurance criterion (MAC). Finally, a new three dimensional design chart is produced, showing the effect of crack location and depth on the natural frequencies of the rotating beam. This chart will be subsequently important in identifying crack defects in rotating blades.