A modified element-free Galerkin method with essential boundary conditions enforced by an extended partition of unity finite element weight function

2003 ◽  
Vol 57 (11) ◽  
pp. 1523-1552 ◽  
Author(s):  
Marcelo Krajnc Alves ◽  
Rodrigo Rossi
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Weight Function ◽  
Galerkin Method ◽  
Partition Of Unity ◽  
Element Free Galerkin Method ◽  
Element Free Galerkin ◽  
Element Free

scholarly journals Bernstein polynomials in element-free Galerkin method

2011 ◽  
Vol 225 (8) ◽  
pp. 1808-1815 ◽  
Author(s):  
O F Valencia ◽  
F J Gómez-Escalonilla ◽  
D Garijo ◽  
J L Díez
Keyword(s):  
Boundary Conditions ◽  
Galerkin Method ◽  
Bernstein Polynomials ◽  
Partition Of Unity ◽  
Particle Method ◽  
Moving Least Squares ◽  
Shape Functions ◽  
Element Free Galerkin Method ◽  
Element Free Galerkin ◽  
Element Free

In the recent decades, meshless methods (MMs), like the element-free Galerkin method (EFGM), have been widely studied and interesting results have been reached when solving partial differential equations. However, such solutions show a problem around boundary conditions, where the accuracy is not adequately achieved. This is caused by the use of moving least squares or residual kernel particle method methods to obtain the shape functions needed in MM, since such methods are good enough in the inner of the integration domains, but not so accurate in boundaries. This way, Bernstein curves, which are a partition of unity themselves, can solve this problem with the same accuracy in the inner area of the domain and at their boundaries.

Implementing of Displacement Boundary Conditions of Element-Free Galerkin Method and its Applications Used in Fracture Mechanics

2012 ◽  
Vol 629 ◽  
pp. 606-610
Author(s):  
Gang Cheng ◽  
Wei Dong Wang ◽  
Dun Fu Zhang
Keyword(s):  
Boundary Conditions ◽  
Galerkin Method ◽  
Reproducing Kernel ◽  
Particle Method ◽  
Transformation Method ◽  
Computational Method ◽  
Reproducing Kernel Particle Method ◽  
Element Free Galerkin Method ◽  
Element Free Galerkin ◽  
Element Free

The main draw back of the Moving Least Squares (MLS) approximate used in element free Galerkin method (EFGM) is its lack the property of the delta function. To alleviate difficulties in the treatment of essential boundary conditions in EFGM, the local transformation method and the boundary singular weight method, which are used in the reproducing kernel particle method, is combined with the element free Galerkin method. The computational method is given to analyze the stress intensity factors and the numerical simulation of crack propagation of two-dimentional problems of the elastic fracture analysis. The application examples reveal the effectiveness and feasibility of the present methods.

A Coupled Finite Element-Element Free Galerkin Method for Liquefiable Soil-Structure Interaction Analysis Under Earthquake Loading

2009 ◽  
Author(s):  
Xiaowei Tang ◽  
Ying Jie ◽  
Maotian Luan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Galerkin Method ◽  
Soil Structure ◽  
Soil Structure Interaction ◽  
Element Free Galerkin Method ◽  
Structure Interaction ◽  
Element Free Galerkin ◽  
Liquefiable Soil ◽  
Element Free

This study presents a numerical method for the seismic behavior assessment of liquefiable soil-structure interaction. In the method, the element-free Galerkin method (EFGM) is applied to simulate the behavior of the liquefiable sandy soil which will take place large permanent deformation under earthquake loading. The finite element method (FEM) is used to describe the behavior of the structure. Then, the EFGM and FEM are related by contact elements. The cyclic elasto-plastic constitutive model and updated Lagrangian large-deformation formulation are jointly adopted to establish the governing equations in order to take account for both physical and geometrical nonlinearities. The shape function is established by moving least squares method while hexahedral background cells are used. The essential boundary conditions are treated with the help of the penalty method. The coupled method can avoid the volumetric locking in the numerical computations using finite element method when non-uniform deformations happen. In order to assess the effectiveness and accuracy of the current procedure, numerical simulation of caisson-type quay wall subjected to earthquake motion is conducted.

Experimental and numerical comparisons between finite element method, element-free Galerkin method, and extended finite element method predicted stress intensity factor and energy release rate of cortical bone considering anisotropic bone modelling

2019 ◽  
Vol 233 (8) ◽  
pp. 823-838 ◽  
Author(s):  
Ajay Kumar ◽  
Pankaj Shitole ◽  
Rajesh Ghosh ◽  
Rajeev Kumar ◽  
Arpan Gupta
Keyword(s):  
Finite Element Method ◽  
Stress Intensity Factor ◽  
Finite Element ◽  
Galerkin Method ◽  
Extended Finite Element Method ◽  
Extended Finite Element ◽  
Element Free Galerkin Method ◽  
Element Free Galerkin ◽  
Element Free ◽  
Element Method

Stress intensity factor and energy release rate are important parameters to understand the fracture behaviour of bone. The objective of this study is to predict stress intensity factor and energy release rate using finite element method, element-free Galerkin method, and extended finite element method and compare these results with the experimentally determined values. For experimental purpose, 20 longitudinally and transversely fractured single-edge notched bend specimens were prepared and tested according to ASTM standard. All specimens were tested using the universal testing machine. For numerical simulations (finite element method, element-free Galerkin method, and extended finite element method), two-dimensional model of cortical bone was developed by assuming plane strain condition. Material properties of the cortical bone were considered as anisotropic and homogeneous. The values obtained through finite element method, element-free Galerkin method, and extended finite element method are well corroborated to experimentally determined values and earlier published data. However, element-free Galerkin method and extended finite element method predict more accurate results as compared to finite element method. In the case of the transversely fractured specimen, the values of stress intensity factor and energy release rate were found to be higher as compared to the longitudinally fractured specimen, which shows consistency with earlier published data. This study also indicates element-free Galerkin method and extended finite element method predicted stress intensity factor and energy release rate results are more close to experimental results as compared to finite element method, and therefore, these methods can be used in the different field of biomechanics, particularly to predict bone fracture.

Some Advantages of the Elliptic Weight Function for the Element Free Galerkin Method

2005 ◽  
Author(s):  
Reza Naghdabadi ◽  
Mohsen Asghari
Keyword(s):  
Weight Function ◽  
Galerkin Method ◽  
Computational Cost ◽  
Characteristic Parameter ◽  
Major Influence ◽  
Element Free Galerkin Method ◽  
Element Free Galerkin ◽  
Influence Radius ◽  
Anisotropic Weight ◽  
Element Free

In this paper, an anisotropic weight function in the elliptic form is introduced for the Element Free Galerkin Method (EFGM). In the circular (isotropic) weight function, each node has one characteristic parameter that determines its domain of influence. In the elliptic weight function, each node has three characteristic parameters that are major influence radius, minor influence radius and the direction of the major influence. Using the elliptic weight function each point of the domain may be affected by a less number of nodes in certain conditions. Thus, the computational cost of the method is decreased. In addition, the dependency of the solution on the method that is used for the enforcement of the essential boundary conditions, decreases. As an application of the proposed elliptic weight function, some examples of elastostatic problems are solved and the results are compared with those available in the literature.

Applying Element-Free Galerkin Method to Simulate Die Forging Problems

2010 ◽  
Vol 139-141 ◽  
pp. 1174-1177 ◽  
Author(s):  
Di Li ◽  
Jia Chuan Xu ◽  
Wen Qian Kang
Keyword(s):  
Finite Element ◽  
Galerkin Method ◽  
Friction Model ◽  
Deformation Analysis ◽  
Element Free Galerkin Method ◽  
Rigid Plastic ◽  
Element Free Galerkin ◽  
Die Forging ◽  
Point Subset ◽  
Element Free

The analysis for die forging forming problems with finite element method can lose considerable accuracy due to severely distortional meshes. The element-free Galerkin method is suitable for large deformation analysis and provides a higher rate of convergence than that of the conventional finite element methods. A rigid-plastic meshless method based on the element-free Galerkin method has been applied to die forging problems. The arc-tangent friction model is used to handle frictional contact and the penalty method is applied to impose the volumetric incompressibility conditions. By dividing all integration points set into the point subset of the rigid zones and the point subset of the plastic zones, nonsmoothness of the rigid-plastic constitutive relation can be eliminated. A die forging example has been analyzed to demonstrate the performance of the method.

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