Research on Aircraft Skin Microcrack Detection Method Based on Coda Wave Interference
The detection limit of conventional ultrasonic non-destructive testing methods is half of the wavelength of ultrasonic waves,making it difficult to detect early microcrack damage to the fuselage skin.The article explored the possibility of using the coda wave interference method in seismology for early detection of skin microcracks.Firstly,a theoretical model of the coda wave was established,and the propagation characteristics of the coda wave signal were explained by the random walk and impact process of particles in the Markov chain.A skin model was constructed using the finite element tool Abaqus to clarify the origin of the coda wave signal in the skin material.Secondly,a series of skin models with crack damage levels at the micrometer level was built,and the coda wave signal was associated with the micro crack damage characteristics of the skin.The simulation results show that as the size of microcracks and the deflection angle of microcracks increase,the corresponding relative variation of coda wave velocity also increases linearly,and the growth of microcrack size has a dominant impact on the variation of coda wave relative ve-locity.Finally,a coda wave experimental platform was built,and the experimental results verify that the coda wave method has higher detection accuracy than conventional ultrasonic testing methods.
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