Fractality of Simulated Fracture

2009 ◽  
Vol 409 ◽  
pp. 154-160 ◽  
Author(s):  
Petr Frantík ◽  
Zbyněk Keršner ◽  
Václav Veselý ◽  
Ladislav Řoutil
Keyword(s):  
Numerical Model ◽  
Elastic Plate ◽  
Model Simulation ◽  
Element Model ◽  
The Other ◽  
Particle Model ◽  
Discrete Element Model ◽  
Fractal Nature ◽  
Discrete Elements ◽  
The Impact

The paper is focussed on numerical simulations of the fracture of a quasi-brittle specimen due to its impact onto a fixed rigid elastic plate. The failure of the specimen after the impact is modelled in two ways based on the physical discretization of continuum: via physical discrete elements and pseudo-particles. Advantages and drawbacks of both used methods are discussed. The size distribution of the fragments of the broken specimen resulting from physical discrete element model simulation follows a power law, which indicates the ability of the numerical model to identify the fractal nature of the fracture. The pseudo-particle model, on the other side, can successfully predict the kinematics of the fragments of the specimen under impact failure.

A CUBIC ARRANGED SPHERICAL DISCRETE ELEMENT MODEL

2014 ◽  
Vol 11 (05) ◽  
pp. 1350102 ◽  
Author(s):  
WEI GAO ◽  
YUANQIANG TAN ◽  
MENGYAN ZANG
Keyword(s):  
Strain Energy ◽  
Element Model ◽  
Discrete Element ◽  
Discrete Element Model ◽  
Laminated Plate ◽  
Discrete Elements ◽  
Elastic Continuum ◽  
Vibration Process ◽  
Spring Constants ◽  
Dem Model

A 3D discrete element model (DEM model) named cubic arranged discrete element model is proposed. The model treats the interaction between two connective discrete elements as an equivalent "beam" element. The spring constants between two connective elements are obtained based on the equivalence of strain energy stored in a unit volume of elastic continuum. Following that, the discrete element model proposed and its algorithm are implemented into the in-house developed code. To test the accuracy of the DEM model and its algorithm, the vibration process of the block, a homogeneous plate and laminated plate under impact loading are simulated in elastic range. By comparing the results with that calculated by using LS-DYNA, it is found that they agree with each other very well. The accuracy of the DEM model and its algorithm proposed in this paper is proved.

scholarly journals Modelling the impact of microbial contamination of fuel filtration efficiency

2017 ◽  
Vol 169 (2) ◽  
pp. 133-136
Author(s):  
Rafał KRAKOWSKI
Keyword(s):  
Numerical Model ◽  
Microbial Contamination ◽  
Petroleum Products ◽  
Filtration Efficiency ◽  
The Other ◽  
Entire System ◽  
Factors Influencing ◽  
Three Stages ◽  
The Impact ◽  
Growth Of Bacteria

In this paper the concept of filtration and the problem of microbial contamination occurring in the fuels and oils was presented. Then the factors influencing the growth of bacteria in petroleum products were described in detail. In the next part of the article modeling of the impact of fuel microbial contamination on filtration efficiency was performed. The modeling presented in the article is an example showing how undesirable phenomenon is the microbial contamination and how pollution affects the other elements of the entire system. As part of the modeling, numerical model of filtration with the solution was presented. Then analysis results on the basis of the impurities concentration characteristics in the fuel as a function of the fouling thickness in the partition of the filter is performed. The development of impurities was divided into three stages. In the article for one case the trend line was presented. The article was completed conclusions.

FE Modeling of the Three-Layer Human Carotid Artery Under Impact Loadings

2007 ◽  
Author(s):  
Aihong Zhao ◽  
Ken Digges ◽  
Mark Field ◽  
David Richens
Keyword(s):  
Finite Element ◽  
Carotid Artery ◽  
Model Simulation ◽  
Material Model ◽  
Element Model ◽  
Traumatic Rupture ◽  
Aortic Tissue ◽  
Fe Model ◽  
Arbitrary Lagrangian Eulerian ◽  
The Impact

Blunt traumatic rupture of the carotid artery is a rare but life threatening injury. The histology of the artery is key to understanding the aetiology of this injury. The carotid artery is composed of three layers known as the tunica intima, media, and adventitia, with distinct biomechanical properties. In order to examine the behaviour of the carotid artery under external load we have developed a three layer finite element model of this vessel. A rubber-like material model from LS-DYNA was selected for the FE model. The Arbitrary-Lagrangian Eulerian (ALE) approach was adopted to simulate the interaction between the fluid (blood) and the structure (carotid). To verify the FE model, the impact bending tests are simulated using this FE model. Simulation results agree with tests results well. Furthermore, the mechanical behaviour of carotid artery tissues under impact loading were revealed by the simulations. The results provide a basis for a more in-depth investigation of the carotid artery in vehicle crashes. In addition, it provides a basis for further work on aortic tissue finite element modeling.

Coupled Discrete Element/Finite Element Method for the Analysis of Large Reinforced Concrete Structures Submitted to an Impact

2011 ◽  
Vol 82 ◽  
pp. 284-289
Author(s):  
Laurent Daudeville ◽  
Jessica Haelewyn ◽  
Philippe Marin ◽  
Serguei Potapov
Keyword(s):  
Reinforced Concrete ◽  
Finite Elements ◽  
Heterogeneous Media ◽  
Concrete Slab ◽  
Element Model ◽  
Discrete Element ◽  
Discrete Elements ◽  
Reinforced Concrete Slab ◽  
The Impact ◽  
Element Method

The efficiency of the discrete element method for studying the fracture of heterogeneous media has been demonstrated, but it is limited by the size of the computational model. A coupling between the discrete elements (DEM) and the finite elements (FEM) methods is proposed to handle the simulation of impacts on large structures. The structure is split into two subdomains in each of which the method is adapted to the behavior of the structure under impact. The DEM takes naturally into account the discontinuities and is used to model the media in the impact zone. The remaining structure is modeled by the FEM. We propose an adaptation of the coupling procedure to connect Discrete Element model to shell-type Finite Elements. Finally, the efficiency of this approach is shown on the simulation of a reinforced concrete slab impacted by a tubular impactor.

Discrete Element Simulation of Powder Sintering for Spherical Particles

2020 ◽  
Vol 854 ◽  
pp. 164-171
Author(s):  
Ilia I. Beloglazov ◽  
Aleksei V. Boikov ◽  
Pavel A. Petrov
Keyword(s):  
Numerical Model ◽  
Model Simulation ◽  
Bulk Material ◽  
Experimental Studies ◽  
Spherical Shape ◽  
Discrete Element ◽  
Spherical Particles ◽  
Large Set ◽  
Discrete Elements ◽  
Powder Sintering

This paper presents a numerical simulation of powder sintering. The numerical model presented in this paper uses the discrete element method, which suggests that the material can be modeled by a large set of discrete elements (particles) of a spherical shape that interact with each other. A methodology has been developed to determine the DEM parameters of bulk materials based on machine vision and a neural network algorithm. The approach is suitable for obtaining the exact values of the DEM parameters of the investigated bulk material by comparing the visual images of the material’s behavior at the experimental stand in reality and in the model. Simulation of sintering requires an introduction of cohesive interaction between particles representing interparticle sintering forces. Numerical sintering studies were supplemented with experimental studies that provided data for calibration and model validation. The experimental results have shown a significant capability of the designed numerical model in modeling sintering processes. Evolution of microstructure and density during sintering have been studied under the laboratory conditions.

Dynamic Response of Hammer Impacting Pile under Gravity Field

2014 ◽  
Vol 610 ◽  
pp. 65-69
Author(s):  
Dong Hua Chen ◽  
Li Quan Wang
Keyword(s):  
Numerical Model ◽  
Dynamic Response ◽  
Gravity Field ◽  
Impact Energy ◽  
Model Simulation ◽  
Gravitational Potential Energy ◽  
Impact System ◽  
Pile Cap ◽  
Hammer Impact ◽  
The Impact

Pile hammer impact system is composed of hammer, pile cap and pile. Gravity field will produce uneven stress in the pile which is placed on a fixed rigid plane, and gravitational potential energy will increase the impact energy which is inputted to the pile during the impact process. These will influence dynamic response of collision process between pile hammer and pile. In this paper, a gravity field factor was added in the Simth difference equations which are based on One-dimensional Wave Equation. The numerical model of pile hammer impact system was established. A program was written to implement the numerical model. Simulation results indicated that the duration of collision, the peak and stable value of impact force and the effective impact energy would be affected by the gravity field.

Dynamics of Large Membrane for Solar Sail-Craft

2007 ◽  
Author(s):  
Koji Nakaya ◽  
Shuhei Nishimaki ◽  
Osamu Mori ◽  
Jun’Ichiro Kawaguchi
Keyword(s):  
Numerical Model ◽  
Numerical Simulations ◽  
Particle Method ◽  
Solar Sail ◽  
The Other ◽  
Particle Model ◽  
Balloon Experiment ◽  
Japan Aerospace Exploration Agency

This paper discusses dynamics of large membrane for achieving spinning solar sail-craft proposed by the Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA). For comprehending the dynamics, firstly, two types of grand-scale experiments were conducted. One was an ice rink experiment. The other was a balloon experiment. In the both experiments, we succeeded in deploying 10m and 20m diameter membrane and observing the motion. Secondly, we constructed a numerical model using a multi-particle method, and numerical simulations were conducted. We drew a comparison between results of experiments and numerical simulations. The effectively of the multi-particle model was then indicated in this paper.

A Global Simulation Model for Hermetic Reciprocating Compressors

1991 ◽  
Vol 113 (3) ◽  
pp. 395-400 ◽  
Author(s):  
M. A. de los Santos ◽  
S. Cardona ◽  
J. Sa´nchez-Reyes
Keyword(s):  
Theoretical Model ◽  
Simulation Model ◽  
Modal Analysis ◽  
Degrees Of Freedom ◽  
Element Model ◽  
Discrete Element Model ◽  
Lagrange Equations ◽  
The Impact ◽  
Three Degrees Of Freedom ◽  
Elastic Elements

This article presents a simulation model for reciprocating hermetic compressors. The acoustical behavior of both admission and discharge circuits is analyzed by invoking the discrete element model. Cavities are considered as elastic elements and ducts as rigid elements with inertia according to this model. Reed valves are modeled as systems of three degrees of freedom, and are studied by using modal analysis. The percussive version of Lagrange equations is used to describe the impact between valves and stops or seats. Results from the theoretical model are checked with those experimentally obtained for a real compressor.

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