Hybrid Finite-Discrete Element Modelling of Various Rock Fracture Modes during Three Conventional Bending Tests

2022 ◽  
Vol 14 (2) ◽  
pp. 592
Author(s):  
Huaming An ◽  
Shunchuan Wu ◽  
Hongyuan Liu ◽  
Xuguang Wang
Keyword(s):  
Strain Rate ◽  
Rock Fracture ◽  
Discrete Element ◽  
Discrete Element Modelling ◽  
Bending Tests ◽  
Main Fracture ◽  
Rock Mechanism ◽  
Fracture Types ◽  
Force Displacement ◽  
Fracture Processes

The numerical techniques for modelling the rock fracture have been briefly reviewed. A hybrid finite-discrete element method (HFDEM) is proposed to simulate various fracture types of rock. A fracture model is implemented in the HFDEM for simulation of the three main fracture types. In addition, the influence of the strain rate is considered during the HFDEM modelling rock behavior. Then, two typical rock mechanism tests are employed to calibrate the HFDEM. The proposed method has well modelled the rock fracture processes and can obtain reasonable stress distribution and force–displacement curves. After that, the HFDEM is used to model three convention bending tests. The obtained rock fracture processes indicates that the HFDEM can simulate various fracture types. The obtained rock strengths and fracture toughness indicate that the HFDEM can reflect the influence of the strain rate. It is concluded that the HFDEM can model the entire and complete rock fracture process during the three convention bending tests, and it also can capture the rock’s behavior on the strain rate.

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.

scholarly journals Impact Fracture and Fragmentation of Glass via the 3D Combined Finite-Discrete Element Method

2021 ◽  
Vol 11 (6) ◽  
pp. 2484
Author(s):  
Zhou Lei ◽  
Esteban Rougier ◽  
Earl E. Knight ◽  
Mengyan Zang ◽  
Antonio Munjiza
Keyword(s):  
Discrete Element Method ◽  
Automobile Industry ◽  
Glass Plate ◽  
Discrete Element ◽  
Impact Fracture ◽  
Constitutive Relationship ◽  
Laminated Glass ◽  
Fracture Patterns ◽  
Fracture Processes ◽  
Element Method

A driving technical concern for the automobile industry is their assurance that developed windshield products meet Federal safety standards. Besides conducting innumerable glass breakage experiments, product developers also have the option of utilizing numerical approaches that can provide further insight into glass impact breakage, fracture, and fragmentation. The combined finite-discrete element method (FDEM) is one such tool and was used in this study to investigate 3D impact glass fracture processes. To enable this analysis, a generalized traction-separation model, which defines the constitutive relationship between the traction and separation in FDEM cohesive zone models, was introduced. The mechanical responses of a laminated glass and a glass plate under impact were then analyzed. For laminated glass, an impact fracture process was investigated and results were compared against corresponding experiments. Correspondingly, two glass plate impact fracture patterns, i.e., concentric fractures and radial fractures, were simulated. The results show that for both cases, FDEM simulated fracture processes and fracture patterns are in good agreement with the experimental observations. The work demonstrates that FDEM is an effective tool for modeling of fracture and fragmentation in glass.

scholarly journals A new time-delayed periodic boundary condition for discrete element modelling of railway track under moving wheel loads

2021 ◽  
Vol 23 (4) ◽  
Author(s):  
Huiqi Li ◽  
Glenn McDowell ◽  
John de Bono
Keyword(s):  
Boundary Condition ◽  
Periodic Boundary Condition ◽  
Periodic Boundary ◽  
Discrete Element ◽  
Contact Forces ◽  
Railway Track ◽  
Discrete Element Modelling ◽  
Fixed Boundary ◽  
Element Modelling ◽  
New Time

Abstract A new time-delayed periodic boundary condition (PBC) has been proposed for discrete element modelling (DEM) of periodic structures subject to moving loads such as railway track based on a box test which is normally used as an element testing model. The new proposed time-delayed PBC is approached by predicting forces acting on ghost particles with the consideration of different loading phases for adjacent sleepers whereas a normal PBC simply gives the ghost particles the same contact forces as the original particles. By comparing the sleeper in a single sleeper test with a fixed boundary, a normal periodic boundary and the newly proposed time-delayed PBC (TDPBC), the new TDPBC was found to produce the closest settlement to that of the middle sleeper in a three-sleeper test which was assumed to be free of boundary effects. It appears that the new TDPBC can eliminate the boundary effect more effectively than either a fixed boundary or a normal periodic cell. Graphic abstract

Discrete element modelling of track ballast capturing the true shape of ballast stones

2021 ◽  
Vol 386 ◽  
pp. 144-153
Author(s):  
Jacob Mortensen ◽  
Joachim Faldt Faurholt ◽  
Emil Hovad ◽  
Jens Honoré Walther
Keyword(s):  
Discrete Element ◽  
Discrete Element Modelling ◽  
Element Modelling ◽  
True Shape
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