Experimental and Numerical Free Vibration Analysis of Laminated Composite Plates with Arbitrary Cut-Outs

Cut-outs are the integral parts of laminated plate components in a variety of civil, aerospace and marine engineering applications. Cut-outs alter the dynamic behaviour of the structures by reducing mass and stiffness simultaneously. The glass epoxy laminates are fabricated by resin infusion method through vacuum bagging system in the laboratory. The experimental studies are carried out on composite plates with cut-out positioned at different locations in the laminate. A finite element formulation based on the first-order shear deformation theory is developed in the present study using nine noded isoparametric shallow shell elements. The effects of rotary inertial contribution of mass on the natural frequencies are studied in the present paper. The present finite element formulation is validated by comparing the solutions obtained in terms of natural frequencies with the relevant published results and also experimental data. The correlation between experimental and numerical mode shapes is established by using modal assurance criteria.