Thermo-mechanical post-buckling analysis of variable angle tow composite plate assemblies

The increasing use of composite materials for lightweight structural applications and the extended tailoring capabilities offered by variable stiffness laminates requires rapid and robust analysis tools that adequately describe the mechanical behaviour of such structures. In this work, a Rayleigh-Ritz solution for generally restrained multilayered stiffened variable angle tow plates in the post-buckling regime is presented. The plate model is based on first-order shear deformation theory and accounts for geometrical nonlinearity through von Kármán's assumptions. General symmetric and unsymmetric stacking sequences are considered and Legendre orthogonal polynomials are employed to approximate the unknown displacement field. Stiffened variable angle tow plates are modeled as an assembly of plate-like elements and penalty techniques are used to enforce the displacements continuity of the assembled multidomain structure and also to apply the kinematical boundary conditions. The developed postbuckling analysis is sufficiently versatile to model a wide range of configurations and load cases for multi-component, variable angle tow, composite structures, and provide the same accuracy level as finite element analysis. The proposed solution is validated by comparison with literature and finite elements analysis and original results are presented for the thermo-mechanical post-buckling solution of multilayered stiffened variable angle tow plates. The effectiveness of the developed analysis tool for both stiffened plates and a tapered stiffened wing box is shown, with a reduced number of unknowns and simplified data preparation compared to finite element analysis.