A vibration method for measuring mechanical properties of composite, theory and experiment

This paper presents a method for identifying elastic and damping properties of composite laminates by using vibration test data. The analysis model is established based on a finite element model which considers the effect of transverse shear deformation and hysteretic damping. The reduced elastic constants and material loss factors are selected as the updated parameters. Since the damping mainly causes a change of the imaginary part in eigenvalues and eigenvectors, the complex modal parameters are measured. The selected parameters are identified by minimizing an error function containing the deviations of eigenvalues and responses between experiment and analysis. The numerical study shows that satisfactory results including transverse shear moduli can be obtained by designing a suitable plate specimen. Experimental results demonstrate the efficiency of the proposed method. In principle, the present method allows all elastic constants and damping factors to be determined simultaneously.