Low-Velocity Impact Localization of CFRP Plates Based on Fiber Bragg Grating Using the Inverse Finite Element Method

The multimodal noise during the collision of carbon-fiber-reinforced polymer (CFRP) composite plates and the potential influence of traditional data-driven methods on the mechanical properties of the plates are a problem. This study proposes a low-velocity impact localization method for composite plates using the inverse finite element method (iFEM). The finite element analysis results were initially used as theoretical strain data to verify the effectiveness of the iFEM in low-velocity impact scenarios. The variational mode decomposition (VMD) algorithm was used to decompose the signal, and the Hilbert transform was used to obtain the signal envelope for accurate extraction of the time of arrival (TOA). Extracted strain values were then input into the iFEM to reconstruct the deformation and strain fields of the composite plate. Experimental results demonstrate high localization accuracy in multiple single-point impact tests, with an average error within 8.11 mm. Under certain conditions, the method also achieves correct localization for multipoint impact tests. This study provides a novel technical approach for structure health monitoring of CFRP composite plates.