scholarly journals Slope Failure of Noncohesive Media Modelled with the Combined Finite–Discrete Element Method

2019 ◽  
Vol 9 (3) ◽  
pp. 579 ◽  
Author(s):  
Xudong Chen ◽  
Hongfan Wang
Keyword(s):  
Discrete Element Method ◽  
Large Scale ◽  
Slope Failure ◽  
Discrete Element ◽  
Material Point ◽  
Contact Forces ◽  
Discrete Elements ◽  
Failure Behaviour ◽  
Particle Hydrodynamics ◽  
Element Method

Slope failure behaviour of noncohesive media with the consideration of gravity and ground excitations is examined using the two-dimensional combined finite–discrete element method (FDEM). The FDEM aims at solving large-scale transient dynamics and is particularly suitable for this problem. The method discretises an entity into a couple of individual discrete elements. Within each discrete element, the finite element method (FEM) formulation is embedded so that contact forces and deformation between and of these discrete elements can be predicted more accurately. Noncohesive media is simply modelled with assembly of individual discrete elements without cohesion, that is, no joint elements need to be defined. To validate the effectiveness of the FDEM modelling, two examples are presented and compared with results from other sources. The FDEM results on gravitational collapse of rectangular soil heap and landslide triggered by the Chi-Chi earthquake show that the method is applicable and reliable for the analysis of slope failure behaviour of noncohesive media through comparison with results from other known methods such as the smoothed particle hydrodynamics (SPH), the discrete element method (DEM) and the material point method (MPM).

Smooth particle hydrodynamics and discrete element method coupling scheme for the simulation of debris flows

2020 ◽  
Vol 125 ◽  
pp. 103669 ◽  
Author(s):  
Mario Germán Trujillo-Vela ◽  
Sergio Andrés Galindo-Torres ◽  
Xue Zhang ◽  
Alfonso Mariano Ramos-Cañón ◽  
Jorge Alberto Escobar-Vargas
Keyword(s):  
Discrete Element Method ◽  
Debris Flows ◽  
Discrete Element ◽  
Coupling Scheme ◽  
Smooth Particle Hydrodynamics ◽  
Particle Hydrodynamics ◽  
Element Method

scholarly journals A Numerical Study of Railway Ballast Subjected to Direct Shearing Using the Discrete Element Method

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Hongyi Zhao ◽  
Jing Chen
Keyword(s):  
Discrete Element Method ◽  
Mechanical Performance ◽  
Numerical Study ◽  
Discrete Element ◽  
Contact Forces ◽  
Angle Of Repose ◽  
Particle Rotation ◽  
Railway Ballast ◽  
Depth Analysis ◽  
Element Method

Railway ballast is a coarse granular material used to carry train loads and provide drainage for the rail tracks. This study presents numerical explorations of the mechanical performance of ballast aggregates subjected to direct shear tests. The discrete element method (DEM) was used to investigate the microscopic characteristics of ballast aggregates during shearing while considering contact distribution, particle rotation, and particle displacement. By testing the angle of repose of ballast aggregates, the parameters for the DEM contact model could be calibrated. Four specimens were prepared and then subjected to different normal pressures. The results show that the contact between ballast particles intensifies in terms of the amount and magnitude as the normal pressure increases. A Fourier analysis was applied to investigate the anisotropy of contact normal and the contact forces for ballast aggregates at different shearing phases. The rotational and translational movements of ballast particles were investigated, and this investigation revealed that particle rotation gradually increased as the shearing propagated. Four regions in the aggregates were identified according to the translational pattern of ballast particles. The results of this research provide an in-depth analysis of microscopic characteristics from a particulate scale.

Study on the Particle Behavior in a Screw Conveyer System by the Discrete Element Method

2011 ◽  
Author(s):  
Yusuke Shigeto ◽  
Mikio Sakai ◽  
Shin Mizutani ◽  
Seiichi Koshizuka ◽  
Shuji Matsusaka
Keyword(s):  
Discrete Element Method ◽  
Large Scale ◽  
Discrete Element ◽  
Dem Simulation ◽  
Memory Space ◽  
Industrial Systems ◽  
Simulation Techniques ◽  
Conveyer System ◽  
Grain Model ◽  
Element Method

Large amount of particles are used in the industrial systems. Numerical analyses of these systems are expected to reduce designing cost. However the numerical analysis of powder is not used practically, because it requires high calculation cost which grows up with the number of particles. Besides, there are memory consumption problem which is required for calculation space. In this paper, the parallel simulation techniques of the Discrete Element Method (DEM) on multi-core processors are described. In the present study, it is shown that the algorithm enables all the processes of the DEM to be executed parallel. Moreover, a new algorithm which makes the memory space usage effectively and accelerates the calculation speed is proposed for multi-thread parallel computing of the DEM. In the present study, the memory space usage is shown to be reduced drastically by introducing this algorithm. In addition, the coarse grain model which emulates original particles with less calculation particles is applied in order to reduce calculation cost. For the practical usage of the DEM in industries, the simulation is performed in a large-scale powder system which possesses a complicated drive unit. In the current study, it is shown that the large scale DEM simulation of practical systems is enabled to be executed by our proposing algorithms.

Simulation of Failure of a Fixed Beam Subjected to Impact Load Using Quadrilateral Discrete Element Method

2012 ◽  
Author(s):  
Rajesh P. Nair ◽  
C. Lakshmana Rao
Keyword(s):  
Discrete Element Method ◽  
Impact Analysis ◽  
Mechanical Response ◽  
Impact Load ◽  
Discrete Element ◽  
Failure Criteria ◽  
Discrete Elements ◽  
The Impact ◽  
Fixed Beam ◽  
Element Method

Discrete Element Method (DEM) is an explicit numerical scheme to model the mechanical response of solid and particulate media. In our paper, we are introducing Quadrilateral Discrete Element Method (QDEM) for the simulation of the separation of elements in fixed beam subjected to impact load. QDEM results are compared with other DEM results available in literature. Impact loads include two cases: (a) a half sine wave and (b) a penetrator hitting the fixed beam. Separation criteria used for the discrete elements is maximum principal stress failure criteria. In QDEM, convergence study for the response of fixed beam is obtained using MATLAB platform. Validation of quadrilateral elements in fixed beam is being carried out by comparing the results with empirical formula available in literature for the impact analysis.

scholarly journals ВПЛИВ КОНСТРУКЦІЙ ВІДЦЕНТРОВИХ ЗМІШУВАЧІВ НА ЇХ ЗГЛАДЖУВАЛЬНУ ЗДАТНІСТЬ

2020 ◽  
Vol 142 (1) ◽  
pp. 11-18
Author(s):  
В. В. Стаценко ◽  
О. П. Бурмістенков ◽  
Т. Я. Біла
Keyword(s):  
Discrete Element Method ◽  
Residence Time ◽  
Mixing Time ◽  
Discrete Element ◽  
Point Of View ◽  
Design Parameters ◽  
Discrete Elements ◽  
Bulk Materials ◽  
Design Features ◽  
Element Method

Studying the influence of continuous centrifugal mixers design features on their smoothing ability. The methods used are discrete elements, mathematical modeling and regression analysis. The paper considers five continuous centrifugal mixers designs with conical and parabolic rotors. The mixers design features are determined, allowing to change their smoothing ability. Mathematical models of the bulk materials particles movement inside each mixer have been developed based on the discrete element method. The considered mixers reaction to a step change of the key component amount is investigated. The transients parameters are calculated and the particles average residence time in the mixer is determined. It is established that the introduction of turbulizers in the mixers design increases the particles kinetic energy, which leads to a decrease in their residence time in the mixer. Moreover, the absence of a turbulizer leads to a decrease in the mixing intensity. It was also found that the most effective way to increase the mixer smoothing ability is the introduction of additional rotors. In terms of the technological and design parameters combination, the use of mixers with a conical rotor and a turbulizer is the most effective from the point of view for increasing the smoothing ability. On the discrete element method basis, the bulk materials particles movement models in continuous centrifugal mixers of five designs have been developed. The influence of the mixers design features on their smoothing ability and average mixing time is determined. The results obtained allow us to select the appropriate mixer design according to the specified requirements for smoothing ability.

scholarly journals Complex Failure Simulation of Underinclined Shale Slope Based on Discrete Element Method

2020 ◽  
Vol 24 (1) ◽  
pp. 83-89
Author(s):  
Bin Li ◽  
Da Huang
Keyword(s):  
Discrete Element Method ◽  
Slope Failure ◽  
Slope Angle ◽  
Soft Rock ◽  
Discrete Element ◽  
Failure Patterns ◽  
Site Investigations ◽  
Dip Angle ◽  
Different Parts ◽  
Element Method

A landslide occurred in the cut slope located in Chongqing west railway station, this slope belongs to a under-dip shale slope, which means that its bedding dip angle is larger than slope angle and it is comprised of soft rock. Some on-site investigations have been made to explore the deformation characteristics of this slope, the outcome suggested that sliding, buckling and toppling deformation existed at its different parts. To elucidate the complex failure mechanism exhibited by the under-dip slope under the long-term influence of gravity and material deterioration, the discrete element method has been employed in simulations. The simulated failure patterns have proven to be in strong agreement with the actual slope failure. This study suggests that sliding, buckling and toppling occur at different parts of the studied slope in sequence.

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