Interlaminar fracture toughness evaluation in glass/epoxy composites using Acoustic Emission and Finite Element Methods

Saeedifar, M., Fotouhi, M. , Najafabadi, M. A. and Toudeshky, H. H. (2014) Interlaminar fracture toughness evaluation in glass/epoxy composites using Acoustic Emission and Finite Element Methods. Journal of Materials Engineering and Performance, 24(1), pp. 373-384. (doi: 10.1007/s11665-014-1291-2)

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Abstract

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 in situ 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 (G C). 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 G C 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 G C 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.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Fotouhi, Dr Mohammad
Authors: Saeedifar, M., Fotouhi, M., Najafabadi, M. A., and Toudeshky, H. H.
College/School:College of Science and Engineering > School of Engineering > Aerospace Sciences
Journal Name:Journal of Materials Engineering and Performance
Publisher:Springer
ISSN:1059-9495
ISSN (Online):1544-1024

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