AN APPROACH TO GUIDED-WAVE MODE SELECTION FOR INSPECTION OF LAMINATEDPLATE

Overall philosophy of composite material inspection is discussed with a sample problem presentation to illustrate the utility of guided wave analysis and the use of field distributions across the thickness of a specimen to predict its sensitivity to specific anomalies in the mate rial. Guided Lamb-type waves in a three-layered laminated composite pl ate with different anomaly content is studied in this article. Our wor k is focused primarily on the detection of interlaminar bond layer imp erfections and cracks normal to the interfaces. A Lamb wave mode selec tion criteria is discussed with respect to defect sensitivity analysis . Selection of appropriate modes and frequencies is suggested by an ap proach based on an analysis of the modal displacement and power distri bution across the multilayered structure as opposed to the previously utilized approach based on a numerical analysis of the dispersion rela tions for different boundary conditions and effective material propert ies.