Impact Force Identification on Carbon Fibre–Epoxy Honeycomb Composite Panel Based on Local Convex Curve Criterion

Abstract

Identification of impact force is essential for various engineering applications, such as performance evaluation, design optimisation, noise suppression, and vibration control. There are two categories available for impact force identification, namely, direct measurement and indirect acquisition. For actual engineering structures, direct measurement is often not feasible. Therefore, indirect acquisition, or force identification, is the only means to achieve this goal. Owing to the existence of noise, ill-posedness occurs during the inversion process of force identification, which is the decisive factor for the instability and inaccuracy of this method. The most popular among the existing methods for impact force identification is the Tikhonov regularisation method. The accuracy of this method depends on the determination of the regularisation parameters. This study proposes a new criterion, which is the local convex curve, for the selection of the regularisation parameter. This criterion is compared with the generalised cross validation, L-curve criterion, and other criteria. A carbon fibre–epoxy honeycomb composite panel is selected as the experimental research object, and three indicators, namely, peak relative error, relative error, and correlation coefficient, are used as the evaluation standards. The experimental results indicate that this new criterion can obtain a superior regularisation parameter in comparison with the other seven criteria. This new criterion can realise the accurate reconstruction of the impact force time history and be effective in suppressing the tail disturbance of the reconstructed impact force time history.