A local defect resonance to enhance acoustic wave-defect interaction in ultrasonic nondestructive evaluation

It is experimentally shown that, to provide maximum acoustic wave-defect interaction, the concept of a local defect resonance should be applied. The model of a resonant defect is used for the selection of the wave frequency to enhance the excitation of the defect in nonlinear acoustics and ultrasonic thermography. An increase in nonlinear response of the defect at its local resonance exceeds substantially the one at natural frequencies of the specimen. The strong wave-defect interaction is confirmed by resonance induced rise of local temperature of the defect in the frequency band of its local resonance. (C) 2011 American Institute of Physics. [doi:10.1063/1.3663872]