Investigation of the effect of spirally stacked fiber reinforcement on the torsional behavior of a polymer composite rod by AE analysis

Abstract

Abstract The fiber orientation of composite materials has a major impact on the mechanical properties, especially the torsional ability of polymer composites. Automobile and aerospace industries are continually on the search for better polymer composite materials to replace rotating metal components. In this research work, spirally stacked basalt and glass fiber polymer composite solid rods are fabricated by Vacuum Assisted Resin Transfer Molding (VARTM) method to study the torsional behavior under static torsional loading conditions. In order to predict the different failure initiation in the composite materials like matrix cracking, de-bonding and fiber fracture, the Acoustic emission sensor and its signal analysis are used. Time domain, Frequency domain (Fast Fourier Transformation) and Discrete Wavelet Pocket Transformation methods are used to identify the approximate signal levels for different material failure modes. ‘k’-means cluster analysis is also carried out to identify frequency spectrum related to the various failure mechanisms. The observed frequency ranges for different failures are 0 to 100 kHz for matrix failure, 100 to 240 kHz for debonding and 240 to 500 kHz for fiber fractures. The time domain and FFT analysis results are observed to agree with the k-means clustering results and with fractrography of the tested samples.