Titolo

A simple locking free hybrid model, using unsymmetric stresses, for
Reissner-Mindlin plates.

Abstract

In the conference a simple mixed-hybrid element for linear analysis of
Reissner-Mindlin plates is presented. The element is derived from a modified
Reissner functional and standard bilinear (isoparametric ) interpolation for
displacement and rotations is assumed , whereas local stresses (rather than
stress resultants and moments) are explicitely modelled. It is assumed that
in plane shear stresses ar not a priori symmetric. This choice allows the
decoupling of equilibrium equations, and involves introducing an in plane
infinitesimal rotation field, corresponding to drilling dofs. The proposed
element does not exhibit locking effects at all: i.e., the shear deformation
energy is zero in the thin plate limit case. Details of the formulations
are provided, and the performances of the element are assessed with reference
to well-estabilished benchmark problems.