An adaptive time domain deconvolution technique to characterize planar flaws in highly attenuative composites

To identify planar heterogeneities or flaws inside a structure using ultrasonic tests, it is necessary to characterize reflections originating from the boundaries of the heterogeneities. However, for composite materials with high, frequency-dependent wave attenuation, it is often not possible to clearly identify the reflections with either A-scan signals or conventional deconvolution techniques due to the combined effect of signal distortion and overlap. To enable deconvolution of a distorted propagating wave, a new time domain deconvolution technique which includes the frequencydependent acoustic properties of the host material has been developed. This approach is shown to be superior to conventional time domain deconvolution with L1 norm minimization in resolving flaw reflections in highly attenuative glass fiber reinforced polyurethane composites.