Stability analysis of variable stiffness composite laminated cylindrical panels containing delamination

A finite strip method is formulated in order to extract the stability characteristics of laminated composite cylindrical panels containing embedded square delamination region. The material properties are assumed to vary along the panel axial length of any lamina according to a linear fiber orientation variation. The effects of existence of a square delamination region are studied on the stability characteristics of the curved panel. The friction effects, contact conditions, and delamination growth phenomenon at delaminated interfaces and edges are overlooked. The natural frequencies of the panel have been investigated based on two composite micromechanical schemes. The dynamic behavior of the delaminated panel has been extracted through using an enhanced B-spline finite strip method formulated based on the principle of virtual work. A third-order Reddy-type shear deformation theory is utilized in order to bring the effects of moderately thick laminate in to account besides a Koiter-Sanders strain-displacement theory of shallow shells. The effects of material volume fractions, layup, micromechanical model, delamination size, and location on dynamic stability characteristics of the structure are studied. In order to demonstrate the capabilities of the developed method in predicting the structural dynamic behavior, some representing results are obtained and compared with those available in the literature.