Robust TRIA3 and QUAD4 Finite Elements Based on the En-Rzt Kinematics for the Analysis of General Anisotropic Multilayered Composite Plates

A new set of robust finite elements for the analysis of general anisotropic multilayered composite plates was presented. Recently, the enhanced-refined zigzag theory (en-RZT) has shown its accuracy in predicting the structural response of laminated plates exhibiting a high transverse anisotropy. Moreover, the en-RZT requires only C⁰ -continuous shape functions to formulate accurate and efficient finite elements. The formulation of three-node triangular (TRIA3) and four-node quadrilateral (QUAD4) flat finite elements based on the en-RZT kinematics was focused. In order to eliminate the shear-locking effect that affects low-order C⁰ -based elements, the constrained anisoparametric interpolation strategy and an appropriate element shear correction (ESC) factor were implemented at the element level. Then, the variational consistent triangular (enRZT-T3c) and quadrilateral (enRZT-Q4c) element were obtained and numerically assessed. A detailed analysis has been performed to evaluate the convergence behavior of the newly formulated elements for bending and free-vibration problems. The influence of the mesh distortion, load configurations, and boundary conditions were finely addressed. The results provided and comparisons with 3D models demonstrate the accuracy and robustness of enRZT-T3c and enRZT-Q4c elements for a wide variety of problems and laminate configurations, including ultra-thin arbitrarily oriented multilayered plates.