Residual Strength of Damaged GFRP Specimens - Testing by Lamb Wave Analysis.
Restfestigkeit von impactgeschädigten Glasfaserverbundproben Untersuchungen mittels Impulswellenanalyse
Frank Berning, Klaus Eberle
ABSTRACT The lamb wave analysis is a non destructive test method (NDT) which is used to examine GFRP specimens damaged by impact. The reported test series aims to correlate NDT results and residual strength by means of samples being damaged on different energy levels. Applying such a correlation function to a part damaged by an impact of unknown energy, the loss of strength and safety can be estimated. The NDT method introduced here is based on ultrasonically induced Lamb waves and their distortion in damaged areas. Wave deflections in thin GFRP plates are recorded along a line parallel to the direction of the wave propagation. The wave fields around a series of damages with different sizes are each analysed and the change in wave amplitudes results in a single characteristic damage parameter. This parameter is plotted versus the damaging energy and provide a diagram which can be used to estimate the residual strength of a part with an impact of unknown energy.
Publication Source: Materialprüfung, ISSN: 0025-5300
Issue: 2003-4, pp 158-162
Publisher: Carl Hanser Verlag München
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