Application of discrete element method for validity evaluation of rock dynamic fracture toughness measured by semi-circular bend technique

2011 ◽  
pp. 1213-1216
Author(s):  
T Kazerani ◽  
J Zhao
Keyword(s):  
Fracture Toughness ◽  
Discrete Element Method ◽  
Dynamic Fracture ◽  
Discrete Element ◽  
Dynamic Fracture Toughness ◽  
Element Method ◽  
Validity Evaluation

Exploring the Fracture Toughness of Tessellated Materials With the Discrete-Element Method

2019 ◽  
Vol 86 (11) ◽  
Author(s):  
Najmul Abid ◽  
Florent Hannard ◽  
J. William Pro ◽  
Francois Barthelat
Keyword(s):  
Fracture Toughness ◽  
Discrete Element Method ◽  
Process Zone ◽  
Building Blocks ◽  
Discrete Element ◽  
Polycrystalline Materials ◽  
Intergranular Cracking ◽  
Brick And Mortar ◽  
Architectured Materials ◽  
Element Method

Abstract Architectured materials contain highly controlled structures and morphological features at length scales intermediate between the microscale and the size of the component. In dense architectured materials, stiff building blocks of well-defined size and shape are periodically arranged and bonded by weak but deformable interfaces. The interplay between the architecture of the materials and the interfaces between the blocks can be tailored to control the propagation of cracks while maintaining high stiffness. Interestingly, natural materials such as seashells, bones, or teeth make extensive use of this strategy. While their architecture can serve as inspiration for the design of new synthetic materials, a systematic exploration of architecture-property relationships in architectured materials is still lacking. In this study, we used the discrete element method (DEM) to explore the fracture mechanics of several hundreds of 2D tessellations composed of rigid “tiles” bonded by weaker interfaces. We explored crack propagation and fracture toughness in Voronoi-based tessellations (to represent intergranular cracking in polycrystalline materials), tessellations based on regular polygons, and tessellations based on brick-and-mortar. We identified several toughening mechanisms including crack deflection, crack tortuosity, crack pinning, and process zone toughening. These models show that periodic architectures can achieve higher toughness when compared with random microstructures, the toughest architectures are also the most anisotropic, and tessellations based on brick and mortar are the toughest. These findings are size independent and can serve as initial guidelines in the development of new architectured materials for toughness.

scholarly journals Combined Finite-Discrete Element Modelling of Dynamic Rock Fracture and Fragmentation during Mining Production Process by Blast

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Huaming An ◽  
Yushan Song ◽  
Hongyuan Liu ◽  
Haoyu Han
Keyword(s):  
Discrete Element Method ◽  
Dynamic Fracture ◽  
Rock Fracture ◽  
Fracture Initiation ◽  
Discrete Element ◽  
Underground Mine ◽  
Fragmentation Process ◽  
Discrete Element Modelling ◽  
Sublevel Caving ◽  
Element Method

A combined finite-discrete element method (FDEM) is proposed to model the dynamic fracture, fragmentation, and resultant muck-piling process during mining production by blast in underground mine. The key component of the proposed method, that is, transition from continuum to discontinuum through fracture and fragmentation, is introduced in detail, which makes the proposed method superior to the continuum-based finite element method and discontinuum-based discrete element method. The FDEM is calibrated by modelling the crater formation process by blast. The FDEM has well modelled the stress and fracture propagation and resultant fragmentation process. In addition, the proposed method has well captured the crushed zone, cracked zone, and the radial long crack zone. After that, the FDEM is employed to model the dynamic fracture and resultant fragmentation process by blast during sublevel caving process in an underground mine. Then the FDEM has well modelled the stress propagation process, as well as the fracture initiation and fragmenting process. Finally, the effects of borehole spacing and initial gas pressure are discussed. It is concluded that the FDEM is a value numerical approach to study the dynamic rock fracture process by blast.

Study on Mechanical Properties and Size Effect of Si3N4 Using Discrete Element Method

2009 ◽  
Vol 76-78 ◽  
pp. 719-724 ◽  
Author(s):  
Yuan Qiang Tan ◽  
Sheng Qiang Jiang ◽  
Cai Li ◽  
Dong Min Yang ◽  
Gao Feng Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Compressive Strength ◽  
Size Effect ◽  
Discrete Element Method ◽  
Bending Strength ◽  
Discrete Element ◽  
Poisson's Ratio ◽  
Simulation Results ◽  
Element Method

The mechanical models formed by packed circular discrete elements were used to investigate the mechanical properties of Si3N4. In these models, the distribution of elements is random in the specified region, and the average radius of elements is 6m. The main mechanical properties investigated here are Young’s modulus, compressive strength, Poisson’s ratio, fracture toughness and bending strength. Some numerical simulation analysis of the size effect of the mechanical properties in these discrete element models were carried out. The simulation results suggest that there is no obvious size effect for Young’s modulus, compressive strength and Poisson’s ratio in these discrete element models. However, for bending strength, when the number of elements in model is less than about 9000, there exists obvious size effect, with the increasing of the number of the elements, the size effect will become less and less until disappeared. The value of fracture toughness decreases with the increasing of the number of the model elements. The classical continuum fracture mechanics model about material fracture under tensile stress is also established by discrete element method. The simulation results are just the same as the simulation results of single edge notched bending (SENB) and the experimental values reported in other literatures. The results provide a more reliable foundation for the application of DEM in simulating the mechanical behaviors of advance ceramics.

Discrete element method to model cracking for two layer systems

TAPPI Journal ◽  
2019 ◽  
Vol 18 (2) ◽  
pp. 101-108
Author(s):  
Daniel Varney ◽  
Douglas Bousfield
Keyword(s):  
Discrete Element Method ◽  
Flexural Modulus ◽  
Single Layer ◽  
Discrete Element ◽  
Flexural Stress ◽  
Layer System ◽  
Three Point Bending ◽  
Moving Force ◽  
Coating Layers ◽  
Element Method

Cracking at the fold is a serious issue for many grades of coated paper and coated board. Some recent work has suggested methods to minimize this problem by using two or more coating layers of different properties. A discrete element method (DEM) has been used to model deformation events for single layer coating systems such as in-plain and out-of-plain tension, three-point bending, and a novel moving force picking simulation, but nothing has been reported related to multiple coating layers. In this paper, a DEM model has been expanded to predict the three-point bending response of a two-layer system. The main factors evaluated include the use of different binder systems in each layer and the ratio of the bottom and top layer weights. As in the past, the properties of the binder and the binder concentration are input parameters. The model can predict crack formation that is a function of these two sets of factors. In addition, the model can predict the flexural modulus, the maximum flexural stress, and the strain-at-failure. The predictions are qualitatively compared with experimental results reported in the literature.

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