Finite plate elements with variable kinematics based on sublaminate generalized unified formulation

Abstract

The Sublaminate Generalized Unified Formulation (SGUF) is extended for the first time to the framework of Finite Element Method (FEM) for both displacement-based and mixed (RMVT) formulation. The variable kinematics approach allows to choose different plate models according to the desired level of accuracy. Furthermore, the mixed ESL/LW approach of SGUF makes the model particularly convenient for sandwich structures analysis. A substitute interpolation for the first-order transverse shear strain field, referred to as QC4 interpolation, makes the developed four-node FE locking free and insensitive to mesh distortion. The complete expression of finite element matrices for the PVD-based and RMVT-based elements is provided. The possibility of exactly satisfying transverse stress boundary conditions for RMVT-based elements is also investigated for the first time. The flexibility and accuracy of the computational approach is demonstrated on linear static problems of sandwich plates and beams ranging from global bending response to local indentation problems. In particular, it is demonstrated that the proposed approach is capable of recovering full three-dimensional response with a 2D FE mesh and with less degrees of freedom than the conventional models available in commercial FE packages.