Detection of Different Defects in Carbon Fiber Reinforced Polymer Matrix Laminated Composite under Tension by Vibration Analysis

In this article, different defects in the carbon fiber reinforced polymer matrix laminated composite under tensile loading have been detected by the vibration analysis. For this objective, the tensile test on open-hole composite standard specimens was performed based on the ASTM-D5766 standard. The tensile loading was considered as 2 mm/min, based on the mentioned standard. Acceleration sensors was installed on standard specimens and vibration signals were acquired during tensile loading. In order to detect different defects, in addition to composite standard samples, pure resin and pure fiber specimens were also tested under tensile loading. Signals for pure resin and pure fiber samples were analyzed by the Fourier transform method and signals for open-hole composite standard specimens were analyzed by the wavelet transform approach. Obtained results from the signal analysis showed that the vibration analysis could be a proper method to detect three types of defects in the carbon fiber reinforced polymer matrix laminated composite, including the fiber breakage, matrix cracking and other failures. These other failures were debonding, the delamination and the pull-out. Then also, the maximum percentage of failure mechanisms in the open-hole composite standard samples was due to debonding of fibers from the matrix, the delamination and the pull-out failure. Such these results had an agreement with images from the scanning electron microscopy, which obtained from the fracture surface of standard specimens, after tensile testing.