An improved three-node hybrid-mixed element for Mindlin/Reissner plates

Based on the mixed shear projected (MiSP) approach [6], an enhanced bending approximation for homogeneous isotropic plates is presented. Some hard benchmark tests, as skew plate (30◦) problem for instance, have often shown poor convergence when low order elements (3- or 4-node element) are developed using linear approximations for kinematic variables. To put right this weakness, we propose a high-order interpolation for rotational dofs which results in more rich bending curvatures. The mid-side rotational nodes are eliminated using a combination of local discrete kinematic and constitutive Mindlin hypothesises. The derived 3-node triangular element, called MiSP3+, is free of shear locking and passes all patch-tests for thick and thin plates in an arbitrary mesh