Damping and resonance analysis of a composite cantilever beam

Abstract

This thesis was written in order to study the possibility of obtaining certain mechanical properties, more specifically damping coefficient and resonance frequency, of a material through a non destructive testing method. The testing method implemented was that of a cantilever composite beam, made of carbon fiber, vibrating after an initial displacement. A piezo electric transducer is attached to the beam and a computer’s sound card via a 2.5 mm audio jack, and used to collect vibrational data, which could then be analysed using a Fast Fourier Transform (FFT) and time data analysis through the use of MATLAB. In the case of this study it was found that for a light weight and stiff cantilever beam, the FFT method of analysis provides a resonance frequency with 10 times more certainty than the time domain analysis. The FFT method also provides a damping coefficient which has 10% less variance than that of the time domain analysis.