Ultrasonics of non-linear contacts: propagation, reflection and NDE-applications
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Abstract The results of experimental investigation of acoustic non-linear phenomena on contact boundaries are presented. Simulation experiments demonstrated a threshold non-linear distortion due to ‘clapping’ and ‘kissing’ mechanisms, multiple bifurcations and chaos development for contact vibrations. Hertzian contact non-linearity was shown to increase with the decrease in contact load and to be predominated by a ‘clapping’ mechanism in a mixed mode of vibrations. Ultrasonic waves propagating on contact interfaces exhibited extremely efficient non-linear properties, unconventional higher harmonics ratio and non-linear waveform distortion. Non-linear sound reflection was accompanied by spectrum inversion, rectification and contact radiation broadening effects. Several modes of non-linear non-destructive evaluation (NDE) were proposed and shown to detect small fractured defects ‘invisible’ by linear NDE techniques.
[1] J. S. Wood,et al. Experimental observation of the influence of contact nonlinearity on the reflection of bulk acoustic waves and the propagation of surface acoustic waves , 1991 .
[2] S. Timoshenko,et al. Theory of elasticity , 1975 .
[3] J. S. Wood,et al. ``Popping'' nonlinearity and chaos in vibrations of a contact interface between solids , 1993 .
[4] J. S. Wood,et al. Nonlinear reflection of surface waves at a contact interface between two solids , 1993 .