Sparse signal model for ultrasonic nondestructive evaluation of CFRP composite plates

Signal processing has been proven to be an useful tool to characterize damaged materials under ultrasonic nondestructive evaluation. In this work, we hypothesize that the transfer function of multilayered materials for a through-transmission configuration can be represented as a classical all-pole model with sparse coefficients. To test this hypothesis, we propose an analysis-by-synthesis scheme which, by assuming an underlying sparse digital signal model of the specimen, infers the order and extent of the model parameters corresponding to a certain impact damage level. Then, we exploit the sparse structure of the obtained digital filter for practical NDE applications, with emphasis on impact damage identification of carbon-fiber reinforced polymer plates.