scholarly journals Modelling of triaxial fracture processes in heterogeneous quasi-brittle materials using the Embedded Finite Element Method (E-FEM)

2021 ◽  
Author(s):  
Alejandro Ortega Laborin ◽  
Yann MALECOT ◽  
Emmanuel ROUBIN ◽  
Laurent DAUDEVILLE
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Spherical Inclusion ◽  
Brittle Materials ◽  
Three Dimensions ◽  
Strong Discontinuity ◽  
Homogeneous Material ◽  
Fem Model ◽  
Fracture Processes ◽  
Element Method

This paper studies the use of the Embedded Finite Element Method (E-FEM) for the numerical modelling of triaxial fracture processes in non-homogeneous quasi-brittle materials. The E-FEM framework used in this study combines two kinematics enhancements: a weak discontinuity allowing the model to account for material heterogeneities and a strong discontinuity allowing the model to represent local fractures. The strong discontinuity features enriched fracture kinematics that allow the modelling of all typical fracture modes in three dimensions. A brief review is done of past work using similar enriched finite element frameworks to approach this problem. The work continues by establishing the theoretical basis of each kind of discontinuity formulation and their superposition through the Hu-Washizu variational principle. Afterwards, two groups of simulations have been done for discussing the performance of this combined E-FEM model: homogeneous simulations and simple heterogeneous simulations. Simple homogeneous material simulations aim to test the capabilities of the strong discontinuity model featuring full 3-D kinematics. Simple heterogeneous simulations show numerical applications of the model to the problem of a single spherical inclusion embedded into a homogeneous matrix. Comparisons will be made with another E-FEM model considering a single local fracture mode approach to discuss the differences on the representation of fracture physics under all explored conditions. A concluding statement is made on the benefits and complications identified for the E-FEM framework in this kind of applications.

A Numerical Analysis of the Weak Galerkin Method for the Helmholtz Equation with High Wave Number

2017 ◽  
Vol 22 (1) ◽  
pp. 133-156 ◽  
Author(s):  
Yu Du ◽  
Zhimin Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Error Estimates ◽  
Phase Error ◽  
Three Dimensions ◽  
Wave Number ◽  
Weak Galerkin ◽  
High Wave Number ◽  
Large Wave ◽  
Element Method

AbstractWe study the error analysis of the weak Galerkin finite element method in [24, 38] (WG-FEM) for the Helmholtz problem with large wave number in two and three dimensions. Using a modified duality argument proposed by Zhu and Wu, we obtain the pre-asymptotic error estimates of the WG-FEM. In particular, the error estimates with explicit dependence on the wave numberkare derived. This shows that the pollution error in the brokenH1-norm is bounded byunder mesh conditionk7/2h2≤C0or (kh)2+k(kh)p+1≤C0, which coincides with the phase error of the finite element method obtained by existent dispersion analyses. Herehis the mesh size,pis the order of the approximation space andC0is a constant independent ofkandh. Furthermore, numerical tests are provided to verify the theoretical findings and to illustrate the great capability of the WG-FEM in reducing the pollution effect.

scholarly journals STUDI BANDING PERFORMA TIANG UTAMA BUS UNTUK MODEL TUNGGAL DAN MODEL GANDA DENGAN MENGGUNAKAN SIMULASI METODA ELEMEN HINGGA

2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Budi Setiyana
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fem Model ◽  
Element Method

Sehingga setiap komponen dari bus harus memiliki struktur rangka yang kuat terutama pada tiang utama. Masing-masing tiang utama umumnya dibuat dari sebuah baja profil tunggal (model tunggal). Tetapi tiang utama bus ini juga dapat dibuat dari gabungan dua buah baja profil dengan cara di las (model ganda) yang mempunyai dimensi luar yang sama dengan model tunggal. Penelitian ini bertujuan memodelkan dan membandingkan performa tiang utama sebuah bus untuk tiang model tunggal dan model ganda dengan menggunakan FEM (Finite Element Method). Hasil simulasi FEM adalah berupa tegangan dan displacement. Berdasarkan hasil analisis, didapatkan tegangan dan displacement pada tiang utama model tunggal yaitu berturut turut sebesar 1,287 x 106 N/m2 dan 6,448 x 10-1 mm. Sedangkan tegangan dan displacement pada tiang utama model ganda yaitu berturut turut sebesar 2,936 x 106 N/m2 dan 1,580 mm.  Dari hasil simulasi, bentuk rangka tiang utama yang terbaik adalah tiang utama model tunggal karena memiliki tingat keamanan yang tinggi dibandingkan dengan tiang model ganda baik dari sisi tegangan maupun displacement.Kata kunci: FEM, model tunggal, model ganda, tiang utama

A MSFEM to simulate the eddy current problem in laminated iron cores in 3D

2019 ◽  
Vol 38 (5) ◽  
pp. 1667-1682 ◽  
Author(s):  
Karl Hollaus
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Eddy Current ◽  
Eddy Currents ◽  
Three Dimensional ◽  
Harmonic Balance Method ◽  
Three Dimensions ◽  
Magnetic Vector Potential ◽  
Content Type ◽  
Element Method

Purpose The simulation of eddy currents in laminated iron cores by the finite element method (FEM) is of great interest in the design of electrical devices. Modeling each laminate by finite elements leads to extremely large nonlinear systems of equations impossible to solve with present computer resources reasonably. The purpose of this study is to show that the multiscale finite element method (MSFEM) overcomes this difficulty. Design/methodology/approach A new MSFEM approach for eddy currents of laminated nonlinear iron cores in three dimensions based on the magnetic vector potential is presented. How to construct the MSFEM approach in principal is shown. The MSFEM with the Biot–Savart field in the frequency domain, a higher-order approach, the time stepping method and with the harmonic balance method are introduced and studied. Findings Various simulations demonstrate the feasibility, efficiency and versatility of the new MSFEM. Originality/value The novel MSFEM solves true three-dimensional eddy current problems in laminated iron cores taking into account of the edge effect.

Pipeline On-Bottom Stability Analysis Based on FEM Model

2011 ◽  
Author(s):  
Yong Bai ◽  
Zhimeng Yu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Design Procedure ◽  
Element Model ◽  
The Finite Element Method ◽  
Fem Model ◽  
Engineering Software ◽  
Calculation Results ◽  
Pipeline Design ◽  
Element Method

Pipeline on-bottom stability is one of the sophisticated problems in subsea pipeline design procedure. Due to the uncertainty of the pipe-soil interaction and environment loads, including wave, current, or earthquake, etc., it is classified as the typical nonlinear problem. The Finite Element Method is introduced into pipeline engineering several years ago. More and more special engineering software such as AGA, PONDUS are available in market. However, when doing a project, some abnormal data was found when compared the DnV calculation results and AGA. In order to know the behavior of pipeline on seabed under wave and current load, finite element method – ABAQUS is introduced to do this analysis. The ABAQUS/explicit is used to simulate 600s pipeline dynamic response. The pipeline is supposed to be exposed on seabed and the selected seabed model is large enough to avoid the edge effect. ABAQUS calculation results are compared with the requirements in DnV rules to verify the validity of finite element model.

Coupled Analysis of Structural–Acoustic Problems Using the Cell-Based Smoothed Three-Node Mindlin Plate Element

2016 ◽  
Vol 13 (02) ◽  
pp. 1640007 ◽  
Author(s):  
Z. X. Gong ◽  
Y. B. Chai ◽  
W. Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Solid Mechanics ◽  
Mindlin Plate ◽  
Coupled Analysis ◽  
Plate Element ◽  
Fem Model ◽  
The Face ◽  
Smoothed Finite Element Method ◽  
Element Method

The cell-based smoothed finite element method (CS-FEM) using the original three-node Mindlin plate element (MIN3) has recently established competitive advantages for analysis of solid mechanics problems. The three-node configuration of the MIN3 is achieved from the initial, complete quadratic deflection via ‘continuous’ shear edge constraints. In this paper, the proposed CS-FEM-MIN3 is firstly combined with the face-based smoothed finite element method (FS-FEM) to extend the range of application to analyze acoustic fluid–structure interaction problems. As both the CS-FEM and FS-FEM are based on the linear equations, the coupled method is only effective for linear problems. The cell-based smoothed operations are implemented over the two-dimensional (2D) structure domain discretized by triangular elements, while the face-based operations are implemented over the three-dimensional (3D) fluid domain discretized by tetrahedral elements. The gradient smoothing technique can properly soften the stiffness which is overly stiff in the standard FEM model. As a result, the solution accuracy of the coupled system can be significantly improved. Several superior properties of the coupled CS-FEM-MIN3/FS-FEM model are illustrated through a number of numerical examples.

New Development of the P and H-P Version Finite Element Method with Quasi-Uniform Meshes for Elliptic Problems

2013 ◽  
Vol 444-445 ◽  
pp. 671-675
Author(s):  
Jian Ming Zhang ◽  
Yong He
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Automobile Industry ◽  
Large Scale ◽  
Elliptic Problems ◽  
Three Dimensions ◽  
The Finite Element Method ◽  
New Development ◽  
Engineering Problems ◽  
Element Method

In recent three decades, the finite element method (FEM) has rapidly developed as an important numerical method and used widely to solve large-scale scientific and engineering problems. In the fields of structural mechanics such as civil engineering , automobile industry and aerospace industry, the finite element method has successfully solved many engineering practical problems, and it has penetrated almost every field of today's sciences and engineering, such as material science, electricmagnetic fields, fluid dynamics, biology, etc. In this paper, we will overview and summarize the development of the p and h-p version finite element method, and introduce some recent new development and our newest research results of the p and h-p version finite element method with quasi-uniform meshes in three dimensions for elliptic problems.

The Elasticity-Plasticity Analysis of Composite Foundation with Lime-Soil Pile by FEM

2012 ◽  
Vol 170-173 ◽  
pp. 762-765
Author(s):  
Ying Cui ◽  
Guang Wei Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Carrying Capacity ◽  
Stress Ratio ◽  
Composite Foundation ◽  
The Finite Element Method ◽  
Fem Model ◽  
The Status ◽  
As Stress ◽  
Element Method

With a certain actual lime-soil pile composite foundation project for background, the Finite Element Method (FEM) model of composite foundation was carried out by using the Drucker-Prager theory and ANSYS FEM procedure. By imitating the status of composite foundation under the construction load and analyzing the factors such as stress, settlement, stress ratio between pile and soil, carrying capacity of composite foundation with lime-soil pile has been gained. The conclusions offer some beneficial references to design and construction of actual projects.

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