CFRP Barely Visible Impact Damage Inspection Based on Nonlinear Ultrasound Signal Sparse Reconstruction

In the whole life time of carbon fiber reinforced plastic (CFRP) component, it will inevitably suffer from low-energy impact (LEI) loads, which may lead to barely visible impact damage (BVID). Thus, non-destructive testing of impact damage has attracted more and more attention. In this paper, the detection of BVID in CFRP plates induced by LEI is investigated by means of nonlinear ultrasound with the help of signal sparse reconstruction with overcomplete dictionary obtained from the training of the acquired responses of the undamaged component. A damage inspection and structural health monitoring (SHM) framework for the CFRP component is proposed. The intact CFRP plate specimen and specimens with 12- and 16-J BVID were tested using the proposed method. Experimental results have shown that all the BVIDs could be detected effectively using a short segment of response signal. The proposed method has potential application in instrumentation design for unsupervised damage inspection and SHM during daily maintain in the service of the CFRP material.