On accurate estimation of transverse stresses in multilayer laminates

Abstract

New numerical algorithms are proposed for the accurate evaluation of transverse stresses in general composite and sandwich laminates. A set of higher-order theories with C⁰ isoparameteric finite elements and exact three-dimensional equilibrium equations are used. The integration of the equilibrium equations is carried out through exact surface fitting method, direct integration method and forward and central direct finite difference methods. Sixteen- and nine-noded quadrilateral Lagrangian elements with selective numerical integration techniques based on Gauss-Legendre product rules are used in the analysis. Validity of the present numerical techniques and the higher-order theories are demonstrated by comparing the present results with the available elasticity and other closed-form solutions for cross-ply, angle-ply and sandwich laminates. The exact surface fitting method is seen to give accurate estimate of the transverse stresses compared to other methods.