Issue 52

A. Ayadi et alii, Frattura ed Integrità Strutturale, 52 (2020) 148-162; DOI: 10.3221/IGF-ESIS.52.13 148 Elastoplastic analysis of plane structures using improved membrane finite element with rotational DOFs Ayadi Ayoub, Meftah Kamel University of Biskra, Laboratoire de Génie Energétique et Matériaux, LGEM, Faculty of Sciences and Technology, Biskra, 07000, Algeria a.ayadi@univ-biskra.dz k.meftah@univ-biskra.dz , http://orcid.org/0000-0002-5671-602X Sedira Lakhdar University of Biskra, Laboratoire de Génie Mécanique, LGM, Faculty of Sciences and Technology, Biskra, 07000, Algeria l.sedira@univ-biskra.dz, http://orcid.org/0000-0003-1735-2195 A BSTRACT . In this work, the small-strain elastoplastic behavior of structures is analyzed using an improved nonlinear finite element formulation. In this framework, an eight-node quadrilateral finite element denoted PFR8 (Plane Fiber Rotation) that belongs to the set of elements with rotational degrees of freedom is developed. Its formulation stems from the plane adaptation of the Space Fiber Rotation (SFR) concept that considers virtual rotations of nodal fiber within the element. This approach results in an enhancement of the displacement vector approximation. Von-Mises yield criteria have been applied for yielding of the materials along with the associated flow rule. Newton-Raphson method has been used to solve the nonlinear equations. To assess the performance of the proposed element, benchmark problems are addressed and the results are compared with some analytical and numerical solutions from the literature. K EYWORDS . Elasto-plasticity; Nonlinear analysis; Membrane finite element; Plane Fiber Rotation; Rotational DOFs. Citation: Ayadi, A., Meftah, K., Sedira, L., Elastoplastic analysis of plane structures using improved membrane finite element with rotational DOFs, Frattura ed Integrità Strutturale, 52 (2020) 148-162. Received: 22.11.2019 Accepted: 03.02.2020 Published: 01.04.2020 Copyright: © 2020 This is an open access article under the terms of the CC-BY 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. I NTRODUCTION onlinear problems arise in almost all disciplines of science and engineering practice. In structural mechanics, nonlinear analysis has emerged as a powerful platform for evaluation the performance of structural systems at the life safety and collapse prevention levels [1]. The literature on nonlinear structural behavior has highlighted several types of nonlinearities including geometric, material, kinematic and force nonlinearities [2]. In recent years, a large N