Technique to minimize couplant-effect in acoustic nonlinearity measurements

A modified technique to measure acoustic nonlinearity in fatigued components is proposed in this paper. The advantage of the proposed technique is that it minimizes measurement errors due to the couplant between the transducers and the specimen. Measurements are performed on a fatigued steel 4340 specimen and the coefficients of variation of the nonlinearity parameter are calculated. It is shown that the coefficients of variation of the nonlinearity parameter obtained using the proposed technique are approximately half of that obtained using the conventional technique. (c) 2006 Acoustical Society of America.