Ultrasonic guided wave Modal Analysis Technique(UMAT) for defect detection

Abstract

A new ultrasonic vibration technique is presented to bridge the gap between ultrasonic wave propagation and modal analysis vibration methods, both used in Nondestructive Evaluation (NDE) and S tructural Health Monitoring (SHM). The technique is fast; only one sender and a f ew receiver locations are necessary; defect-detection potential sizes are somewhere between what is expected for the ultrasonic guided wave and modal analysis methods. Sections of an odd shaped test component can be completely hidden or covered. Only a small area must be accessible. It is shown that sensitivity is based on a carefully selected ultrasonic loading function in utilizing the principles of waves and vibrations. Phase velocity dispersion curves, wave structures, reflection factor analysis and classical modal analyses are essential in the work efforts. Sample FEM and experimental results are presented for isotropic metals and anisotropic composite materials to demonstrate the concept. Excellent results are obtained. Future directions are also discussed. ©2010 Society for Experimental Mechanics Inc.