An integrated modeling of barely visible impact damage imaging of CFRP laminates using pre-modulated waves and experimental validation

Nonlinear ultrasonic techniques have been broadly used for detecting barely visible impact damage (BVID) in carbon fiber reinforced plastic (CFRP) from both numerical and experimental approaches. However, the interaction between the BVID and nonlinear ultrasonic is not considered in the currently available numerical models and BVID needs to be more accurately modeled. This work presented an integrated three-dimensional (3D) finite element (FE) model for imaging BVID using pre-modulated wave (PMW) technique, in which the 3D Hashin damage criterion and energy-based damage evolution are introduced to predict intralaminar and interlaminar damage during the impact process. The non-contact PMW tests based on a laser scanning Doppler vibrometer (LSDV) are adopted to experimentally validated the proposed numerical methodology. The results show that the BVID predicted by the FE model agrees well with the experiments. Then, the damage contour images based on frequency spectra of modulation are illustrated to identify the presence of BVID, and damage severity is quantified based on the proposed maximum response amplitude (MRA). It is found that the location of BVID can be identified by the PMW approach numerically and experimentally and the sum of MRA of sidebands exhibits the best sensitivity of the variation of BVID with different energies.