A Lamb-wave-based technique for damage detection in composite laminates

Abstract

This paper presents the application of Lamb waves to inspect damage in compositelaminates. The proposed methodology employs a network of transducers that are used tosequentially scan the structure before and after the presence of damage by transmittingand receiving Lamb wave pulses. A damage localization image is reconstructed byanalyzing the cross-correlation of the scatter signal envelope with the excitation pulseenvelope for each transducer pair. A potential damage area is then reconstructed bysuperimposing the image observed from each actuator and sensor signal path. Bothnumerical and experimental case studies are used to verify the proposed methodology forcomposite laminates. Three-dimensional finite element models with a transducer networkconsisting of four transducer elements are used in the numerical case studies. Theexperimental case studies employ a transducer network using four piezoelectrictransducers as transmitter elements and a laser vibrometer to measure the responsesignals at four locations close to the transducers. The results show that the methodenables the reliable detection of structural damage with locating inaccuracies ofthe order of a few millimeters inside as well as outside of an inspection area of100 × 100 mm2.