Free vibration studies on plates with central cut-out

The present work deals with the experimental and finite element free vibration studies on isotropic and laminated anti-symmetric angle-ply composite plates with central cut-out under clamped-free–clamped-free boundary condition. The natural frequencies were determined using the CQUAD8 finite element of MSC/NASTRAN and comparison made between the experimental values and the finite element solution. The effects of aspect ratio, cut-out size and cut-out shape on the natural frequencies of plates were studied. The experimental values of the first, second and third natural frequencies are in good agreement with those of the finite element solution in the case of both isotropic and laminated composite plates with and without cut-outs. The non-dimensional frequency coefficient Kf are found increases with increase in length-to-cut-out size ratio (d/a) irrespective of the cut-out shape. In case of laminated composite plates, the non-dimensional frequency coefficient Kf increases monotonically with an increase in the aspect ratio irrespective of hole size and shapes for all the three modes of vibration. © 2018, Deutsches Zentrum für Luft- und Raumfahrt e.V.