Implementation of the Smoothed Finite Element Method using 10-node Tetrahedral Elements into a General Purpose Finite Element Software

2018 ◽  
Vol 2018.31 (0) ◽  
pp. 171
Author(s):  
Yuki ONISHI
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
General Purpose ◽  
Finite Element Software ◽  
Tetrahedral Elements ◽  
Smoothed Finite Element Method ◽  
Element Method

F-Bar Aided Edge-Based Smoothed Finite Element Method with 4-Node Tetrahedral Elements for Static Large Deformation Elastoplastic Problems

2019 ◽  
Vol 16 (05) ◽  
pp. 1840010 ◽  
Author(s):  
Yuki Onishi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Large Deformation ◽  
Element Formulation ◽  
Tetrahedral Elements ◽  
Smoothed Finite Element Method ◽  
New Type ◽  
Displacement Based ◽  
Edge Based ◽  
Element Method

A new type of smoothed finite element method (S-FEM), F-barES-FEM-T4, is demonstrated in static large deformation elastoplastic cases. F-barES-FEM-T4 combines the edge-based S-FEM (ES-FEM) and the node-based S-FEM (NS-FEM) for 4-node tetrahedral (T4) elements with the aid of the F-bar method in order to resolve the major issues of Selective ES/NS-FEM-T4. As well as most of the other S-FEMs, F-barES-FEM-T4 inherits pure displacement-based formulation and thus has no increase in DOF. Moreover, the cyclic smoothing procedure introduced in F-barES-FEM-T4 is effective to adjust the smoothing level so that pressure checkerboarding (oscillation) is suppressed reasonably. Some examples of static large deformation analyses for elastoplastic materials proof the excellent performance of F-barES-FEM-T4 in contrast to the conventional hybrid T4 element formulation.

Hexahedral-Based Smoothed Finite Element Method Using Volumetric-Deviatoric Split for Contact Problem

2018 ◽  
Vol 940 ◽  
pp. 84-88 ◽  
Author(s):  
Kai Oshiro ◽  
Hiroka Miyakubo ◽  
Masaki Fujikawa ◽  
Chobin Makabe
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Contact Problem ◽  
Large Strain ◽  
Deformation Gradient ◽  
Deformation Analysis ◽  
Tetrahedral Elements ◽  
Incompressible Materials ◽  
Smoothed Finite Element Method ◽  
Element Method

A first-order hexahedral (H8)-element-based smoothed finite element method (S-FEM) with a volumetric-deviatoric split for nearly incompressible materials was developed for highly accurate deformation analysis of large-strain problems. In the proposed method, the isovolumetric part of the deformation gradient at the integration point is derived from F based on the beta finite element method (i.e., an S-FEM), whereas the volumetric part of the deformation gradient is derived from F on the basis of the standard FEM with reduced integration elements. This method targets H8 elements that are automatically generated from tetrahedral elements, which makes it quite practical. This is because the FE mesh can be created automatically even if the targeted object has a complex shape. This method eliminates the phenomena of volumetric and shear locking, and reduces pressure oscillations. The proposed method was implemented in the commercial FE software Abaqus and applied to the large-deformation contact problem to verify its effectiveness.

An Efficient Finite Element Algorithm in Elastography

2016 ◽  
Vol 08 (03) ◽  
pp. 1650037 ◽  
Author(s):  
Eric Li ◽  
W. H. Liao
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Soft Tissues ◽  
Tetrahedral Mesh ◽  
Tetrahedral Elements ◽  
Time Harmonic ◽  
Smoothed Finite Element Method ◽  
Complicated Geometry ◽  
First Time ◽  
Element Method

Elastography is an imaging approach to measure the stiffness of tissues to provide diagnostic information. Currently, finite element method (FEM) has been widely used in elastography. However, FEM tends to an overly stiff model that sometimes gives unsatisfactory accuracy, particularly using triangular elements in 2D or tetrahedral elements in 3D. In general, it is difficult or even impossible to generate quadrilateral or brick elements to precisely capture the anatomic details for mechanobiologic modeling as the biologic system can be rather sophisticated. In addition, biologic soft tissues are often considered as “incompressible” materials, where conventional FEM could suffer from volumetric locking in numerical solution. On the other hand, linear triangular and tetrahedral mesh can be automatically generated for complicated geometry, which significantly saves the time for the creation of model. With these reasons, for the first time, smoothed finite element method (SFEM) is developed to analyze elastography problems. A range of numerical examples, including static, dynamic, viscoelastic and time harmonic cases have exemplified herein to validate that SFEM is able to provide more accurate and stable solutions using the same set of mesh compared with the standard FEM. Furthermore, SFEM is also effective to inversely compute the mechanical properties of abnormal tissue.

scholarly journals Development of User Element Routine (UEL) for Cell-Based Smoothed Finite Element Method (CSFEM) in Abaqus

2019 ◽  
Vol 17 (02) ◽  
pp. 1850128 ◽  
Author(s):  
Pramod Y. Kumbhar ◽  
A. Francis ◽  
N. Swaminathan ◽  
R. K. Annabattula ◽  
S. Natarajan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Salient Feature ◽  
Three Dimensions ◽  
Benchmark Problems ◽  
Element Analysis ◽  
Finite Element Software ◽  
Linear Elastostatics ◽  
Smoothed Finite Element Method ◽  
Element Method

In this paper, we discuss the implementation of a cell-based smoothed finite element method (CSFEM) within the commercial finite element software Abaqus. The salient feature of the CSFEM is that it does not require an explicit form of the derivative of the shape functions and there is no need for isoparametric mapping. This implementation is accomplished by employing the user element subroutine (UEL) feature in Abaqus. The details on the input data format together with the proposed user element subroutine, which forms the core of the finite element analysis are given. A few benchmark problems from linear elastostatics in both two and three dimensions are solved to validate the proposed implementation. The developed UELs and the associated input files can be downloaded from https://github.com/nsundar/SFEM_in_Abaqus .

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