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.

The transporting efficiency and mechanical behavior analysis of scraper conveyor

2017 ◽  
Vol 232 (18) ◽  
pp. 3315-3324 ◽  
Author(s):  
Xuewen Wang ◽  
Bo Li ◽  
Shaowei Wang ◽  
Zhaojian Yang ◽  
Liu Cai
Keyword(s):  
Particle Size ◽  
Discrete Element Method ◽  
Contact Area ◽  
High Efficiency ◽  
Impact Load ◽  
Frictional Coefficient ◽  
Discrete Element ◽  
Scraper Conveyor ◽  
The Impact ◽  
Element Method

Scraper conveyor is the main equipment for underground coal transportation, and its high-efficiency and smooth operation is of great significance to safety production. This study simulated the process of transporting bulk coal by the scraper conveyor using the discrete element method. Transporting efficiency of scraper conveyor affected by the chain speed, static frictional coefficient, particle size, and laying angle was studied. Then the relationship between the chain speed, static frictional coefficient and the chute wear was explored. The stress and deformation characteristics of the chute during the transportation were studied by coupling the discrete element method and finite element method. Results showed that the mass flow rate changed significantly with the chain speed and static frictional coefficient, while it varied slightly with the change of particle size and laying angle; the higher chain speed and larger bulk coal led to more serious wear of the chute, and large stress mainly concentrated at the direct contact area and the area under the impact load from the bulk coal. Therefore, when designing the chute structure, it is necessary to ensure the wear resistance and strength of the contact area on the chute. The results could provide a theoretical basis for structural optimization of scraper conveyor.

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.

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.

Continuum theory for rapid cohesive-particle flows: general balance equations and discrete-element-method-based closure of cohesion-specific quantities

2017 ◽  
Vol 832 ◽  
pp. 345-382 ◽  
Author(s):  
Kevin M. Kellogg ◽  
Peiyuan Liu ◽  
Casey Q. LaMarche ◽  
Christine M. Hrenya
Keyword(s):  
Kinetic Theory ◽  
Discrete Element Method ◽  
Impact Velocity ◽  
Normal Component ◽  
Discrete Element ◽  
Granular Temperature ◽  
Success Factor ◽  
Particle Flows ◽  
The Impact ◽  
Element Method

The continuum description of rapid cohesive-particle flows comprises the population balance, which tracks various agglomerate sizes in space and time, and kinetic-theory-based balances for momentum and granular energy. Here, fundamental closures are provided in their most general form. In previous population balances, the probability (‘success factor’) that a given collision results in agglomeration or breakage has been set to a constant even though it is well established that the outcome of a collision depends on the impact (relative) velocity. Here, physically based closures that relate the success factors to the granular temperature, a (continuum) measure of the impact velocity, are derived. A key aspect of this derivation is the recognition that the normal component of the impact velocity dictates whether agglomeration occurs. With regard to the kinetic-theory balances, cohesion between particles makes the collisions more dissipative, thereby decreasing the granular temperature. The extra dissipation due to cohesion is accounted for using an effective coefficient of restitution, again determined using the derived distribution of normal impact velocities. This collective treatment of the population and kinetic-theory balances results in a general set of equations that contain several parameters (e.g. critical velocities of agglomeration) that are cohesion-specific (van der Waals, liquid bridging, etc.). The determination of these cohesion-specific quantities using simple discrete element method simulations, as well as validation of the resulting theory, is also presented.

scholarly journals Evaluating the Seismic Capacity of Dry-Joint Masonry Arch Structures via the Combined Finite-Discrete Element Method

2021 ◽  
Vol 11 (18) ◽  
pp. 8725
Author(s):  
Wangpeng Li ◽  
Xudong Chen ◽  
Hongfan Wang ◽  
Andrew H. C. Chan ◽  
Yingyao Cheng
Keyword(s):  
Finite Element ◽  
Discrete Element Method ◽  
Discrete Element ◽  
Element Formulation ◽  
Discrete Elements ◽  
Seismic Capacity ◽  
Masonry Arch ◽  
Highly Nonlinear ◽  
Arch Structures ◽  
Element Method

The behaviour of dry-joint masonry arch structures is highly nonlinear and discontinuous since they are composed of individual discrete blocks. These structures are vulnerable to seismic excitations. It is difficult for traditional methods like the standard finite element method (FEM) to simulate masonry failure due to their intrinsic limitations. An advanced computational approach, i.e., the combined finite-discrete element method (FDEM), was employed in this study to examine the first-order seismic capacity of masonry arches and buttressed arches with different shapes subjected to gravity and constant horizontal acceleration. Within the framework of the FDEM, masonry blocks are discretised into discrete elements. A finite element formulation is implemented into each discrete element, providing accurate predictions of the deformation of each block and contact interactions between blocks. Numerical examples are presented and validated with results from the existing literature, demonstrating that the FDEM is capable of capturing the seismic capacities and hinge locations of masonry arch structures. Further simulations on geometric parameters and friction coefficient of masonry buttressed arches were conducted, and their influences on the seismic capacities are revealed.

scholarly journals Music of grain crushing with the Discrete Element Method

2021 ◽  
Vol 249 ◽  
pp. 07009
Author(s):  
Li Zeng ◽  
Andres Alfonso Peña Olarte ◽  
Roberto Cudmani
Keyword(s):  
Discrete Element Method ◽  
3D Visualization ◽  
Acoustic Emissions ◽  
Discrete Element ◽  
Compression Tests ◽  
Compression Process ◽  
Practical Applications ◽  
Grain Crushing ◽  
The Impact ◽  
Element Method

A series of compression tests on agglomerates of microspheres representing a single grain are conducted to investigate the impact of heterogeneity on the acoustic emissions (AE) generation. The grain heterogeneity is realized by using a Weibull shape parameter-augmented traditional discrete element method (DEM). During the compression process the development of the micro-cracks, and the magnitude and location of the AE events are tracked and recorded. Through a 3D visualization of the AE events, their location and the clustered broken bonds are identified. The current study demonstrates the potential of AE measurements to track changes in the fabric and structure of granular materials. The results of this DEM study will contribute to clarify the mechanism of particle breakage and its consideration in practical applications.

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