Bending behavior and damage evolution of GLARE laminate using in‐situ AE technology and FEM

Abstract

AbstractGLARE laminate experiences multiple damage modes during bending failure, including fiber fracture, matrix cracking, interlayer delamination, and fracture of aluminum alloy. In most cases, two or more failure modes occur together, which makes the damage process complex and unpredictable. This paper proposes a combination of experimental testing and numerical simulation to investigate the influence of fiber lay‐up direction and center open‐hole on the bending failure behavior of GLARE laminate. Simultaneously, Acoustic Emission (AE) technology was used to monitor the bending process of GLARE laminates in real‐time, and a numerical simulation model for the three‐point bending of GLARE laminates was established. The experimental results showed that the bending strength of intact specimens decreased significantly with the increase of the fiber off‐axis angle, whereas the strength retention of open‐hole specimens increased significantly with the increase of the fiber off‐axis angle. Based on the K‐means++ clustering algorithm, the peak frequencies corresponding to different damage modes of GLARE laminates were identified as follows: aluminum alloy damage [1–70 kHz], matrix cracking [93–210 kHz], interlaminar delamination [211–304 kHz], and fiber breakage [304–516 kHz]. The simulation results agreed well with the experimental results, showing that the damage in intact specimens initiated at the laminate edges and propagated sequentially along the thickness direction, while the damage in open‐hole specimens initiated at the hole edges and then propagated towards the laminate edges.Highlights The present study investigated the effects of fiber lay‐up direction and central open‐hole on the bending performance and failure behavior of GLARE laminate. In‐situ monitoring of the GLARE laminate during three‐point bending was conducted using AE technology. A model for simulating the progressive damage of GLARE laminate was established and its accuracy was verified.