Impact damage assessment in laminated composites using acoustic emission and finite element methods

Abstract

This study aims to quantify impact damage in laminated composites using acoustic emission (AE) and to verify the AE results with finite element (FE) method. Carbon fiber reinforced polymer (CFRP) composite specimens were subjected to quasi‐static out‐of‐plane indentation loading. A procedure, including feature extraction, feature selection, data dimensionality reduction, and data clustering using an evolutionary algorithm, that is, differential evolution (DE) optimization algorithm, was proposed to identify and quantify different damage mechanisms using AE. The AE results showed that the dominant damages were matrix cracking and delamination. For the quantitative evaluation of the AE results, the indentation test was simulated using the FE method. A FE model based on cohesive zone modeling and continuum damage mechanics was implemented to predict interlaminar and intralaminar damages. The quantity of the damaged elements associated with the matrix cracking and delamination was consistent with the AE results. This study showed the applicability of the AE for impact damage identification and quantification in composite structures.Highlights Indentation damage in CFRP is experimentally quantified using the AE method. The DE algorithm is used to cluster the AE data. CZM and CDM are used to numerically model the damage. The AE clustering results are compared with the numerical results.

Designing a 3D structure and a self‐healing technique for advanced polymer composites with outstanding mechanical properties and healing ability

“…The LM images of the cross-sections of GFBT after ILSS test show that the layers are obviously delaminated and most of fibers are intact, indicating the poor interaction between the matrix and fibers (Figure 2A 0 ). 71,72 For GFBT10%PPE and GFBT20%PPE, their cross-section images show broken fibers and weak delamination between laminated layers (Figure 2B 0 ,C 0 ), as compared to GFBT, and for GFBT30% PPE, its cross-section image shows some short cracks within composite (Figure 2D 0 ), and no delamination appears between layers, indicating that the addition of PPE can improve the loading force and the interlayer interaction. The LM and 3D images show that the fracture surfaces of GFBTnPPE after tensile test are more irregular than that of GFBT (Figure 2A 00 -D 00 ), indicating GFBTnPPE can consume more energy during the loading process.…”