Interlaminar Fracture Toughness Evaluation in Glass/Epoxy Composites Using Acoustic Emission and Finite Element Methods

Saeedifar, Milad; Fotouhi, Mohamad; Najafabadi, Mehdi Ahmadi; Toudeshky, Hossein Hosseini

Abstract

© 2014, ASM International. Delamination is one of the most common modes of failure in laminated composites and it leads to the loss of structural strength and stiffness. In this paper, mode I, mode II, and mixed of these pure modes were investigated using mechanical data, Finite Element Method (FEM) and Acoustic Emission (AE) signals. Experimental data were obtained from insitu monitoring of glass/epoxy laminated composites with different lay-ups when subjected to different modes of failure. The main objective was to investigate the behavior of delamination propagation and to evaluate the critical value of the strain energy which is required for onset of the delamination (GC). For the identification of interlaminar fracture toughness of the specimens, four methods were used: (a) ASTM standard methods, (b) FEM analysis, (c) AE method, and (d) sentry function method which is a function of mechanical and AE behaviors of the specimens. The results showed that the GC values obtained by the sentry function method and FEM analysis were in a close agreement with the results of nonlinearity methods which is recommended in the ASTM standards. It was also found that the specimens under different loading conditions and various lay-up have different GC values. These differences are related to different stress components distribution in the specimens which induce various damage mechanisms. Accordingly, stress components distribution obtained from FEM analyses were in agreement with SEM observations of the damaged surfaces of the specimens.

• Journal Article Type: Article
• Acceptance Date: Nov 7, 2014
• Online Publication Date: Nov 7, 2014
• Publication Date: Jan 1, 2015
• Deposit Date: Oct 16, 2017
• Publicly Available Date: Oct 16, 2017
• Journal: Journal of Materials Engineering and Performance
• Print ISSN: 1059-9495
• Electronic ISSN: 1544-1024
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 24
• Issue: 1
• Pages: 373-384
• DOI: https://doi.org/10.1007/s11665-014-1291-2
• Keywords: acoustic emission delamination FEM analysis interlaminar fracture toughness sentry function
• Public URL: https://uwe-repository.worktribe.com/output/839212
• Publisher URL: http://dx.doi.org/10.1007/s11665-014-1291-2
• Additional Information: Additional Information : The final publication is available at Springer via http://dx.doi.org/10.1007/s11665-014-1291-2
• Contract Date: Oct 16, 2017