Impact Induced Delamination Detection by Application of Full Wavefield Analysis

Abstract

Comprehensive numerical studies of elastic wave interaction with damage of various sizes and severities which resembles impact damage were performed. Full wavefield signal processing allowed to visualize damaged area and quantify its size by the thresholding damage maps. It was shown that the severity of damage can be quantified by relation of damage map energy in relation to Young’s modulus reduction. It enables to make a step towards damage prognosis. Experimental data of propagating waves in carbon/epoxy laminate acquired by a scanning laser vibrometer revealed that the wave attenuation is highly dependent on angle of propagation. Such behavior strongly affects damage visualization algorithms which are based on a wavenumber filtering. It was shown that this effect can be reduced by the proposed weighting method utilizing propagating elastic wave energy spread. It was also shown that the damage caused by the low impact energy is more difficult to detect and quantify than a delamination simulated by the Teflon insert.