COMMUNICATIONS IN NUMERICAL METHODS IN ENGINEERING Commun. Numer. Meth. Engng 2007; 23:385–403 Published online 7 September 2006 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/cnm.914 A refined 5-node plate bending element based on Reissner–Mindlin theory Hasan Sofuoglu ∗, †, § and Hasan Gedikli ‡, ¶ Department of Mechanical Engineering, Karadeniz Technical University, Trabzon, Turkey SUMMARY In this study, a simple approach was proposed to develop a new 5-node plate bending element, named DRMP. This element formulation is based on the Reissner–Mindlin plate theory and can be used for the analysis of both thin and thick plate. The new element formulation was then coded into FEAP to develop 15-DOF DRMP element for the finite element analysis of plate problems as well as 4-node quadrilateral DRMQ element with 12 DOF. The convergence and usage of DRMP element along with DRMQ element were investigated and the results of the both elements were then compared with the exact solution and the other elements available in the literature. The numerical studies demonstrated that the proposed elements, DRMQ and DRMP, passed the patch test and possessed fast convergence and high accuracy while DRMP element showed the invariability to the fifth node’s position. Moreover, they were independent of the shear locking phenomenon for very thin plates. The presented results showed that 5-node DRMP element can be used along with 4-node quadrilateral DRMQ element where mesh refinement is necessary as a transition element. Copyright 2006 John Wiley & Sons, Ltd. Received 8 January 2006; Revised 10 July 2006; Accepted 26 July 2006 KEY WORDS: Reissner–Mindlin plate; plate bending; refined conforming 4-node element; refined conforming 5-node element 1. INTRODUCTION For the past 40 years, the finite element method has became the most powerful numerical method in the field of solid mechanics, especially for the analysis of plate bending problems since it found wide application in practical engineering. Kirchhoff theory was the first displacement-based ∗ Correspondence to: Hasan Sofuoglu, Department of Mechanical Engineering, Karadeniz Technical University, Trabzon, Turkey. † E-mail: sofuoglu@ktu.edu.tr ‡ E-mail: hgedikli@ktu.edu.tr § Associate Professor. ¶ Assistant Professor. Contract/grant sponsor: Karadeniz Technical University; contract/grant number: 2001.112.003.3 Copyright 2006 John Wiley & Sons, Ltd.