Analysis of the damage mechanisms in mixed-mode delamination of laminated composites using acoustic emission data clustering

Mohamad Fotouhi, Seyedali Sadeghi, Meisam Jalalvand, Mehdi Ahmadi

Research output: Contribution to journalArticle

  • 7 Citations

Abstract

In this study, acoustic emission (AE) technique is used to investigate different time-to-failure mechanisms of delamination in glass/epoxy composite laminates. Woven and unidirectional layups were subjected to the double cantilever beam, end notch flexure, and mixed-mode bending tests and the generated AE signals were captured. Discrimination of the AE events, caused by different types of the damage mechanisms, was performed using wavelet packet transform (WPT) and fuzzy clustering method (FCM) associated with a principal component analysis (PCA). The FCM and WPT analyses identified three dominant damage mechanisms. Furthermore, different interface layups and different GII/GT modal ratio values (ratio of mode II strain energy release rate per total strain energy release rate) indicated different time-to-failure mechanisms incidence. Additionally, the damaged mechanisms were observed using scanning electron microscopic (SEM) analysis. The results showed that the dominant damage mechanisms in all the specimens are matrix cracking and fiber-matrix debonding. Besides, some fiber breakage appeared during the tests, and the percentage of this damage mechanism in the unidirectional specimens and mode I condition was higher than those in the woven specimens and mode II. SEM observations were also in good agreement with the obtained results. It was found that the presented methods can be utilized to improve the characterization and discrimination of damage mechanisms in the actual occurring modes of delamination in composite structures.

LanguageEnglish
Pages318-340
Number of pages23
JournalJournal of Thermoplastic Composite Materials
Volume30
Issue number3
Early online date6 Aug 2015
DOIs
StatePublished - 1 Mar 2017

Fingerprint

Laminated composites
acoustic emission
Acoustic emissions
Delamination
Fuzzy clustering
Energy release rate
Strain energy
damage
composite materials
Scanning
Electrons
Fibers
Debonding
strain energy release rate
Bending tests
Cantilever beams
Composite structures
Principal component analysis
Laminates
discrimination

Keywords

  • acoustic emission
  • Damage mechanism
  • fuzzy c-means clustering
  • laminated composite material
  • wavelet packet transform

Cite this

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abstract = "In this study, acoustic emission (AE) technique is used to investigate different time-to-failure mechanisms of delamination in glass/epoxy composite laminates. Woven and unidirectional layups were subjected to the double cantilever beam, end notch flexure, and mixed-mode bending tests and the generated AE signals were captured. Discrimination of the AE events, caused by different types of the damage mechanisms, was performed using wavelet packet transform (WPT) and fuzzy clustering method (FCM) associated with a principal component analysis (PCA). The FCM and WPT analyses identified three dominant damage mechanisms. Furthermore, different interface layups and different GII/GT modal ratio values (ratio of mode II strain energy release rate per total strain energy release rate) indicated different time-to-failure mechanisms incidence. Additionally, the damaged mechanisms were observed using scanning electron microscopic (SEM) analysis. The results showed that the dominant damage mechanisms in all the specimens are matrix cracking and fiber-matrix debonding. Besides, some fiber breakage appeared during the tests, and the percentage of this damage mechanism in the unidirectional specimens and mode I condition was higher than those in the woven specimens and mode II. SEM observations were also in good agreement with the obtained results. It was found that the presented methods can be utilized to improve the characterization and discrimination of damage mechanisms in the actual occurring modes of delamination in composite structures.",
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Analysis of the damage mechanisms in mixed-mode delamination of laminated composites using acoustic emission data clustering. / Fotouhi, Mohamad; Sadeghi, Seyedali; Jalalvand, Meisam; Ahmadi, Mehdi.

In: Journal of Thermoplastic Composite Materials, Vol. 30, No. 3, 01.03.2017, p. 318-340.

Research output: Contribution to journalArticle

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