Experimental Nonlinear Dynamics of Laminated Quasi-Isotropic Thin Composite Plates

Abstract

Composite panels and plates are increasingly used and continuously developed in diverse industrial domains such as aerospace, automobile, civil and naval structures. However, nonlinear dynamic behavior and failure mechanisms of these structures are still obscure in many respects. A representative example of this issue is nonlinear dynamic behavior of damaged curved composite plates, which is not well represented in the literature although the phenomena could have a detrimental effect on the safety of the aforementioned structures. In this work, free vibrations of (a) an isotropic flat plate (ASTM A36 steel) under fully clamped (CCCC) and cantilever (CFFF) boundary conditions, (b) a symmetrically laminated quasi-isotropic flat composite plate (unidirectional carbon/epoxy) under the same boundary conditions (CCCC and CFFF), and (c) a post-buckled symmetrically laminated quasi-isotropic flat composite plate (carbon fibers woven fabrics) under a clamped and free (CCFF) boundary condition are investigated. A single-point laser is used to capture the dynamic responses of the plates. The von Kármán strain-displacement relations and Rayleigh-Ritz method are employed based on the classical laminated plate theory (CLPT) to establish a theoretical model. This research will ultimately be extended to the nonlinear modeling of vibrations and damage of curved laminated composite plates subjected to large deformations.