Abstract: Composite laminate structures are widely used, and damage identification is of great significance to ensure the safety of structures and prolong their service life. In this paper, the element-level damage indicator is introduced to describe the change of the in-plane and out-plane upward stiffness of laminates. Aiming at the damage index, a two-step damage identification method was established, that is, the damage element was screened by the damage location index, and then the damage degree was identified by the optimization method. The regularization method was used for quantitative damage recognition. Since the traditional regularization method adopts uniform regularization parameters for each damage parameter, which is not conducive to the convergence and stability of the identification results. In this paper, an adaptive regularization damage identification (ARDI) method based on weighting coefficient is proposed, which can improve the identification efficiency while considering the stability of identification results. The effectiveness of the proposed method is verified by numerical examples, and the influence of the number of measurement points and noise level on recognition results is analyzed. The results of the proposed method are compared with the direct method and the traditional regularization method, and it is found that the dispersion of calculation results and the efficiency of the proposed method have obvious advantages. Finally, an experimental work was conducted to verify the effectiveness of the proposed method.

Key words: composite, element-level damage indicator, damage location, adaptive regularization, damage quantification