Analysis of Gossamer Space Structures Using Assumed Strain Formulation Solid Shell Elements

2002 ◽  
Author(s):  
Keejoo Lee ◽  
Sung Lee
Keyword(s):  
Space Structures ◽  
Solid Shell ◽  
Shell Elements ◽  
Assumed Strain ◽  
Strain Formulation

scholarly journals Efficient Solid–Shell Finite Elements for Quasi-Static and Dynamic Analyses and their Application to Sheet Metal Forming Simulation

2015 ◽  
Vol 651-653 ◽  
pp. 344-349 ◽  
Author(s):  
Peng Wang ◽  
Hocine Chalal ◽  
Farid Abed-Meraim
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Large Strain ◽  
Solid Shell ◽  
Forming Process ◽  
Thin Structures ◽  
Shell Elements ◽  
Assumed Strain ◽  
Dynamic Analyses

Thin structures are commonly designed and employed in engineering industries to save material, reduce weight and improve the overall performance of products. The finite element (FE) simulation of such thin structural components has become a powerful and useful tool in this field. For the last few decades, much attention and effort have been paid to establish accurate and efficient FE. In this regard, the solid–shell concept proved to be very attractive due to its multiple advantages. Several treatments are additionally applied to the formulation of solid–shell elements to avoid all locking phenomena and to guarantee the accuracy and efficiency during the simulation of thin structures. The current contribution presents a family of prismatic and hexahedral assumed-strain based solid–shell elements, in which an arbitrary number of integration points are distributed along the thickness direction. Both linear and quadratic formulations of the solid–shell family elements are implemented into ABAQUS static/implicit and dynamic/explicit software to model thin 3D problems with only a single layer through the thickness. Two popular benchmark tests are first conducted, in both static and dynamic analyses, for validation purposes. Then, attention is focused on a complex sheet metal forming process involving large strain, plasticity and contact.

scholarly journals Modeling of thin sheet forming processes by combining solid-shell finite element with isotropic elastoviscoplastic model. Application to magnetic pulse forming processes

2021 ◽  
Author(s):  
Mohamed Mahmoud ◽  
François Bay ◽  
Daniel Pino Mũnoz
Keyword(s):  
Sheet Metal ◽  
Thin Sheet ◽  
Magnetic Pulse ◽  
Solid Shell ◽  
Forming Process ◽  
Thin Structures ◽  
Shell Elements ◽  
Tetrahedral Element ◽  
Magnetic Pulse Forming ◽  
Assumed Strain

Sheet metal alloys are used in many industries to save material, reduce weight and improve the overall performance of products. For the last decades, many types of elements have been developed to resolve the locking problems encountered in the simulation of thin structures. Among these approaches, a family of assumed-strain solid-shell elements has proved to be very efficient and attractive in simulating thin 3D structures with various constitutive models. Furthermore, these elements are able to account for anisotropic behavior of thin structures since isotropic yield functions cannot capture the real physics of some forming processes. In this work, von Mises isotropic yield criterion with Johnson-cook hardening model are combined with a linear prismatic solid-shell element to simulate sheet metal forming processes. A new element assembly technique has been developed to permit the assembly of prismatic elements in a tetrahedral element-based software. This technique splits the prism into multiple tetrahedral elements in such a way that all the cross-terms are accounted for. Furthermore, a tetrahedral based partitioning code has been modified to account for the new prismatic element shape without changing the core structure of the code. More accurate results were obtained using low number of solid-shell elements compared to its counterpart tetrahedral element (MINI element). This reduction in the number of elements accelerated the simulation, especially in the coupled magnetic-structure simulation used for magnetic pulse forming process. The proposed element and criteria are implemented into FORGE (in-house code developed at CEMEF) for simulating magnetic pulse forming process.

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.

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

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.

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
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