Stability of laminated composite curved panels with cutout using finite element method

Abstract

Cutouts are inevitable in structures due to practical consideration. The present study involves vibration and stability of laminated composite curved panels with cutouts using finite element method. The first order shear deformation (FSDT) is used to model the curved panels, considering the effects of transverse shear deformation and rotary inertia. Since the stress field is non-uniform due to cutout, plane stress analysis is carried out using the finite element method to determine the stresses and these are used to formulate the geometric stiffness matrix. The global matrices are obtained using skyline technique. The eigenvalues are obtained us ing subspace iteration scheme. The study reveals that the fundamental frequencies of vibration of an angle ply flat panel decrease with introduction of small cutouts but again rise with increase in size of cutout. However the higher frequencies of vibration continue to decrease up to a moderate size of cutout and then rise with further increase of size of cutout. The stability resistance decreases with increase in size of cutout in curved panels unlike the frequencies of vibration. The buckling loads of cross ply panels reduces drastically with increase in size of cutout compared to angle ply plates. The frequencies of vibration and the stability resistance increase with introduction of curvature in the flat panel with cutout. However, the effect of curvature is reduced with increase of size of cutout.