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Date of Publication:2022-10-10

Journal:计算力学学报

Issue:5

Page Number:663-669,682

ISSN No.:1007-4708

Abstract:A method of crack identification is presented based on amplitude changing after analyzing the dynamic characteristics of cracked beams under harmonic excitation.Firstly,a breathing crack model was introduced to establish a 2-D finite element model of cantilever beam with a crack.It is pointed out that the amplitude is always a significant signal under any excitation and can be used to describe the dynamic characteristics of cracked beams.Secondly,it was found that the amplitudes change differently with crack parameters when the exciting frequency is a quarter of first-order and second-order nature frequency of beams with no cracks.So the amplitude is proposed to detect the crack parameters in beams.Then,the amplitude surface is plotted by adopting surface fitting technology.Through identification of a cracked beam with unknown parameters,the method is proved to be effective.Finally,considering that the nature frequency of a beam with no cracks is calculated inaccurately,the robustness of this method is analyzed. The result shows that this method can detect the crack parameters even though the max error is 10%.

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