ISSN: 1945-7553
CODEN: JTEVAB
Published Online: 23 May 2011
Page Count: 13

A Global Method for the Identification of Failure Modes in Fiberglass Using Acoustic Emission

Arumugam, V.
Department of Aerospace Engineering, Anna University, Chennai,

Kumar, C. Suresh
Department of Aerospace Engineering, Anna University, Chennai,

Santulli, C.
Department of Chemical Engineering, Materials and Environment, Università La Sapienza, Rome,

Sarasini, F.
Department of Chemical Engineering, Materials and Environment, Università La Sapienza, Rome,

Stanley, A. Joseph
MIT Campus, Anna University, Chennai,

(Received 27 December 2010; accepted 20 April 2011)

Abstract

The various failure mechanisms in bidirectional glass/epoxy laminates loaded in tension are identified using acoustic emission (AE) analysis. AE data recorded during the tensile testing of a single layer specimen are used to identify matrix cracking and fiber failure, while delamination signals are characterized using a two-layer specimen with a pre-induced defect. Parametric studies using AE count rate and cumulative counts allowed damage discrimination at different levels of loading and Fuzzy C-means clustering associated with principal component analysis were used to discriminate between failure mechanisms. The two above methods led to AE waveform selection: On selected waveforms, Fast Fourier Transform (FFT) enabled calculating the frequency content of each damage mechanism. Continuous wavelet transform allowed identifying frequency range and time history for failure modes, whilst noise content associated with the different failure modes was calculated and removed by discrete wavelet transform. Short Time FFT finally highlighted the possible failure mechanism associated with each signal.

Keywords:
GFRP, failure modes, acoustic emission, pattern recognition, wavelet analysis

Paper ID: JTE103730
DOI: 10.1520/JTE103730
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