New Nonlinear Buckling Analysis of Variable Angle Tow Composite Cylindrical Shells

It is well recognized that the nonlinear prebuckling state may significantly affect the buckling behavior of shells, but a quantitative theoretical study on this issue is challenging. For variable-angle tow (VAT) composite cylindrical shells, in which mechanical performance is enhanced by tailoring the fiber paths, the influence of the nonlinear prebuckling state on the buckling behavior has been scarcely studied. In this study, new numerical buckling solutions of VAT composite cylindrical shells are obtained by considering the nonlinear prebuckling state. The perturbation method is employed to decompose the governing equation into the nonlinear prebuckling governing equation and the buckling governing equation. Through the state-space method, the prebuckling and buckling governing equations are transformed into the state transition equations and assembled into a global matrix equation that can be solved by a quasi-linearization precise integral method, incorporating the boundary conditions (BCs), to derive the critical buckling load. The obtained solutions exhibit excellent agreement with both the finite element method and the literature results. A comprehensive discussion is performed on the effects of the modulus ratio, the number of layers, BCs, and the tow angle on the critical buckling load and prebuckling displacements. Some useful findings are revealed. For example, using a tow angle design, an accurate tailoring of circumferential deformation could be achieved for an axially compressed VAT laminated cylindrical shell. This study provides a theoretical approach for understanding the complex buckling behavior of VAT composite cylindrical shells in a quantitative way.