Elastic constants of orthotropic composite materials using plate resonance frequencies, classical lamination theory and an optimized three-mode rayleigh formulation

Abstract

This paper shows how the four independent elastic constants (longitudinal and transverse Young's moduli, in-plane shear modulus and major Poisson's ratio) of an orthotropic material may be extracted from the modal resonance data of a freely-supported rectangular thin plate made from the material, using the classical lamination theory and an optimized three-mode Rayleigh formulation with a suitably formed least-squares objective function. Results are obtained for orthotropy ratios of unity (aluminum), about three (unidirectional E-glass/vinylester) and about 13 (graphite/epoxy), and plate aspect ratios of unity and about two. The results suggest that the method proposed has potential for rapid characterization of elastic properties of advanced composites.