scholarly journals Discrete element model for crack propagation in brittle materials

2015 ◽  
Vol 40 (4) ◽  
pp. 583-595 ◽  
Author(s):  
Ba Danh Le ◽  
Georg Koval ◽  
Cyrille Chazallon
Keyword(s):  
Crack Propagation ◽  
Brittle Materials ◽  
Element Model ◽  
Discrete Element ◽  
Discrete Element Model

scholarly journals Identification of the Discrete Element Model Parameters for Rock-Like Brittle Materials

2020 ◽  
Vol 123 (2) ◽  
pp. 717-737 ◽  
Author(s):  
Rui Chen ◽  
Yong Wang ◽  
Ruitao Peng ◽  
Shengqiang Jiang ◽  
Congfang Hu and Ziheng Zhao
Keyword(s):  
Brittle Materials ◽  
Element Model ◽  
Discrete Element ◽  
Model Parameters ◽  
Discrete Element Model

scholarly journals A Discrete Element Model for Damage and Fatigue Crack Growth of Quasi-Brittle Materials

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Xiaofeng Gao ◽  
Georg Koval ◽  
Cyrille Chazallon
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Damage Model ◽  
Brittle Materials ◽  
Element Model ◽  
Discrete Element ◽  
Discrete Element Model ◽  
Single Model ◽  
Stress Intensity Range

The repeatedly applied low-intensity loads would lead to the damage and fatigue crack growth of mechanical structures made of quasi-brittle materials. In numerical modelling, these two mechanisms are normally treated differently and separately; the damage is usually associated with nonlocal approaches, while the fatigue crack growth is related to the local stress intensity range at the crack tip. In this study, a discrete element model for damage and fatigue crack growth of quasi-brittle materials is proposed, which is able to model the damage and fatigue crack growth simultaneously in one single model. The proposed model achieves the implementation of a continuum damage model in a discrete element code, which is a helpful enrichment of this numerical method. The evaluation method of the stress intensity range during the damage evolution provides a way to couple both failure mechanisms. This feature allows crack initiation to be induced by localized damage and a progressive transition to a fracture behaviour with the crack propagation. Independent parameters for the fatigue damage model and fatigue crack growth model are admitted without any previous calibration. The numerical results are in good agreement with the theoretical predictions of damage and fracture mechanics, and intact and precracked samples are analysed under fatigue loading to show the consistent coexistence of fractured and damaged zones in a single model.

scholarly journals Discrete element model for general polyhedra

2021 ◽  
Author(s):  
Alfredo Gay Neto ◽  
Peter Wriggers
Keyword(s):  
Frictional Contact ◽  
Virtual Work ◽  
Particle Surface ◽  
Element Model ◽  
Discrete Element ◽  
Discrete Element Model ◽  
Principle Of Virtual Work ◽  
Dynamics Model ◽  
Railway Ballast ◽  
Multibody Dynamics Model

AbstractWe present a version of the Discrete Element Method considering the particles as rigid polyhedra. The Principle of Virtual Work is employed as basis for a multibody dynamics model. Each particle surface is split into sub-regions, which are tracked for contact with other sub-regions of neighboring particles. Contact interactions are modeled pointwise, considering vertex-face, edge-edge, vertex-edge and vertex-vertex interactions. General polyhedra with triangular faces are considered as particles, permitting multiple pointwise interactions which are automatically detected along the model evolution. We propose a combined interface law composed of a penalty and a barrier approach, to fulfill the contact constraints. Numerical examples demonstrate that the model can handle normal and frictional contact effects in a robust manner. These include simulations of convex and non-convex particles, showing the potential of applicability to materials with complex shaped particles such as sand and railway ballast.

A discrete-element model for viscoelastic deformation and fracture of glacial ice

2015 ◽  
Vol 195 ◽  
pp. 14-22 ◽  
Author(s):  
T.I. Riikilä ◽  
T. Tallinen ◽  
J. Åström ◽  
J. Timonen
Keyword(s):  
Element Model ◽  
Discrete Element ◽  
Discrete Element Model ◽  
Viscoelastic Deformation ◽  
Glacial Ice ◽  
Deformation And Fracture

Study on Machining Mechanism of Glass Using Discrete Element Method

2014 ◽  
Vol 577 ◽  
pp. 108-111 ◽  
Author(s):  
Ying Qiu ◽  
Mei Lin Gu ◽  
Feng Guang Zhang ◽  
Zhi Wei
Keyword(s):  
Discrete Element Method ◽  
Element Model ◽  
Discrete Element ◽  
Rake Angle ◽  
Milling Process ◽  
Micro Milling ◽  
Discrete Element Model ◽  
Machined Surface ◽  
Damage Depth ◽  
Element Method

The discrete element method (DEM) is applied to glass micromachining in this study. By three standard tests the discrete element model is established to match the main mechanical properties of glass. Then, indentating, cutting, micro milling process are simulated. Results show that the vertical damage depth is prevented from reaching the final machined surface in cutting process. Tool rake angle is the most remarkable factor influencing on the chip deformation and cutting force. The final machined surface is determined by the minimum cutting thickness per edge. Different cutting thickness, cutter shape and spindle speed largely effect on the mechanism of glass.

Reduced Rough-Surface Parametrization for Use With the Discrete-Element Model

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Stephen T. McClain ◽  
Jason M. Brown
Keyword(s):  
Heat Transfer ◽  
Rough Surface ◽  
Surface Characterization ◽  
Rough Surfaces ◽  
Roughness Element ◽  
Three Dimensional ◽  
Element Model ◽  
Discrete Element ◽  
Diameter Distribution ◽  
Discrete Element Model

The discrete-element model for flows over rough surfaces was recently modified to predict drag and heat transfer for flow over randomly rough surfaces. However, the current form of the discrete-element model requires a blockage fraction and a roughness-element diameter distribution as a function of height to predict the drag and heat transfer of flow over a randomly rough surface. The requirement for a roughness-element diameter distribution at each height from the reference elevation has hindered the usefulness of the discrete-element model and inhibited its incorporation into a computational fluid dynamics (CFD) solver. To incorporate the discrete-element model into a CFD solver and to enable the discrete-element model to become a more useful engineering tool, the randomly rough surface characterization must be simplified. Methods for determining characteristic diameters for drag and heat transfer using complete three-dimensional surface measurements are presented. Drag and heat transfer predictions made using the model simplifications are compared to predictions made using the complete surface characterization and to experimental measurements for two randomly rough surfaces. Methods to use statistical surface information, as opposed to the complete three-dimensional surface measurements, to evaluate the characteristic dimensions of the roughness are also explored.

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.

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