scholarly journals Development of shear locking-free shell elements using an enhanced assumed strain formulation

2001 ◽  
Vol 53 (7) ◽  
pp. 1721-1750 ◽  
Author(s):  
José M. A. César de Sá ◽  
Renato M. Natal Jorge ◽  
Robertt A. Fontes Valente ◽  
Pedro M. Almeida Areias
Keyword(s):  
Shear Locking ◽  
Shell Elements ◽  
Enhanced Assumed Strain ◽  
Assumed Strain ◽  
Strain Formulation

Further Studies of General Shells by Hybrid Strain Based Triangular Elements

1996 ◽  
Author(s):  
Meilan L. Liu ◽  
Cho W. S. To
Keyword(s):  
Lower Order ◽  
Element Formulation ◽  
Hybrid Strain ◽  
Linear Distribution ◽  
Shell Elements ◽  
Mesh Topology ◽  
Assumed Strain ◽  
Strain Formulation ◽  
Membrane Bending ◽  
Deep Shell

Abstract This paper presents a further study of various lower-order flat triangular shell elements that were based on the Hellinger-Reissner hybrid strain formulation and were developed previously by the authors. The present investigation is to examine the effects of including membrane-bending coupling feature in the shell element formulation on the performance of the lower-order shell elements. Several features are considered. These are, for example, the membrane-bending coupling, tue linear distribution of the assumed strain field of the membrane strain, and the hybrid strain formulation with linear assumed membrane strains and membrane-bending coupling. A study on mesh topology is also included. This relatively detailed study leads one to the conclusion that the hybrid strain based flat triangular shell elements previously developed by the authors are attractive and promising for economical analysis of general shells. It is also found that the inclusion of features such as membrane-bending coupling is unnecessary. Numerical results presented here seem to strongly substantiate the theoretical developments that flat triangular shell elements do converge to the correct solution of deep shell theory. Finally it is observed that for deep shell problems appropriate mesh topology becomes the key to an accurate finite element solution.

Evaluation of the Enhanced Assumed Strain and Assumed Natural Strain in the SSH3D and RESS3 Solid Shell Elements for Single Point Incremental Forming Simulation

2012 ◽  
Vol 504-506 ◽  
pp. 913-918 ◽  
Author(s):  
Carlos Felipe Guzmán ◽  
Amine Ben Bettaieb ◽  
José Ilídio Velosa de Sena ◽  
Ricardo J. Alves de Sousa ◽  
Anne Marie Habraken ◽  
...  
Keyword(s):  
Finite Element ◽  
Incremental Forming ◽  
Single Point ◽  
Single Point Incremental Forming ◽  
Solid Shell ◽  
Shell Elements ◽  
Enhanced Assumed Strain ◽  
Natural Strain ◽  
Assumed Strain ◽  
Assumed Natural Strain

Single Point Incremental Forming (SPIF) is a recent sheet forming process which can give a symmetrical or asymmetrical shape by using a small tool. Without the need of dies, the SPIF is capable to deal with rapid prototyping and small batch productions at low cost. Extensive research from both experimental and numerical sides has been carried out in the last years. Recent developments in the finite element simulations for sheet metal forming have allowed new modeling techniques, such as the Solid Shell elements, which combine the main features of shell hypothesis with a solid-brick element. In this article, two recently developed elements -SSH3D element [1, 2] and RESS3 element [3]- implemented in Lagamine (finite element code developed by the ArGEnCo department of the University of Liège) are explained and evaluated using the SPIF line test. To avoid locking problems, the well-known Enhanced Assumed Strain (EAS) and Assumed Natural Strain (ANS) techniques are used. The influence of the different EAS and ANS parameters are analized comparing the predicted tool forces and the shape of a transversal cut, at the end of the process. The results show a strong influence of the EAS in the forces prediction, proving that a correct choice is fundamental for an accurate simulation of the SPIF using Solid Shell elements.

A Parametric Study for Four Node Bilinear EAS Shell Elements

2010 ◽  
Vol 26 (4) ◽  
pp. 431-438
Author(s):  
Cengiz Polat
Keyword(s):  
Variational Principle ◽  
Transverse Shear ◽  
Strain Field ◽  
Shell Element ◽  
Shell Structures ◽  
Shear Locking ◽  
Shell Elements ◽  
Assumed Strain ◽  
Dependent Strain ◽  
Transverse Shear Locking

ABSTRACTA locking free formulation of 4-node bilinear shell element and its application to shell structures is demonstrated. The Enhanced Assumed Strain (EAS) method based on three-field variational principle of Hu-Washizu is used in the formulation. Transverse shear locking and membrane locking are circumvented by means of enhancing the displacement-dependent strain field with extra assumed strain field. Several benchmark shell problems are analyzed.

Enhanced assumed strain (EAS) and assumed natural strain (ANS) methods for one-point quadrature solid-shell elements

2007 ◽  
Vol 75 (2) ◽  
pp. 156-187 ◽  
Author(s):  
Rui P. R. Cardoso ◽  
Jeong Whan Yoon ◽  
M. Mahardika ◽  
S. Choudhry ◽  
R. J. Alves de Sousa ◽  
...  
Keyword(s):  
Solid Shell ◽  
Shell Elements ◽  
Enhanced Assumed Strain ◽  
Natural Strain ◽  
Assumed Strain ◽  
Assumed Natural Strain
Sign in / Sign up

Export Citation Format

Share Document