Effect of material nonlinearity on buckling and postbuckling of fiber composite laminated plates and cylindrical shells

摘要

An analytical study is presented in this paper on the effect of material nonlinearity on buckling and postbuckling of fiber composite laminate plates and shells subjected to general mechanical loading. The material nonlinearity of the composite is modelled by power-law type, nonlinear shear constitutive equations for each lamina. The nonlinear effective composite constitutive equations in an incremental form are incorporated into a geometrically nonlinear analysis for studying buckling and postbuckling deformations of composite laminate structures. A modified Riks' solution scheme with an updated Lagrangian formulation is used to construct the equilibrium path during composite postbuckling. Numerical examples are given to illustrate the effect of material nonlinearity on buckling load, postbuckling stiffness, and associated mode shape change of a composite structure under axial and pressure loading. Influences of lamination parameters, geometric imperfection, and loading mode on the postbuckling equilibrium path and load-bearing strength of the composite structure with the nonlinear material properties are also studied.