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A discrete element study on the deformation and degradation of coal-fo by Jing Chen, Jayan S Vinod et al

This paper presents the results of Discrete Element Modelling (DEM) which quantitively examine the effect of coal fouling on the deformation and degradation of ballast upon cyclic loading. The degradation model described herein considers the Weibull distribution effects in tandem with a granular medium hardening law that incorporates the maximum contact criterion to capture surface abrasion and corner breakage of angular ballast. The DEM model had been calibrated initially with laboratory data obtained from large-scale direct shear testing. Subsequently, a series of cubical shear test simulations have been carried out using DEM to understand the behaviour of fouled ballast whereby the numerical particle degradation modelling could simulate the experimental response of the ballast assembly at various fouling levels. The results show that the increased level of fouling exacerbates the sleeper settlement, while decreasing the resilient modulus and the particle breakage. Ballast beneath th

Discrete element modellingBallast degradationDiscrete element methodDynamic responsesLeeper settlement

DEM numerical study on mechanical behaviour of coal with different wat by Lihai Tan, Xin Cai et al

The mechanical behaviour and stability of coal mining engineering underground is significantly affected by ground water. In this study, nuclear magnetic resonance imaging (NMRI) technique was employed to determine the water distribution characteristics in coal specimens during saturation process, based on which the functional rule for water distribution was proposed. Then, using discrete element method (DEM), an innovative numerical modelling method was developed to simulate water-weakening effect on coal behaviour considering moisture content and water distribution. Three water distribution numerical models, namely surface-wetting model, core-wetting model and uniform-wetting model, were established to explore the water distribution influences. The feasibility and validity of the surface-wetting model were further demonstrated by comparing the simulation results with laboratory results. The investigation reveals that coal mechanical properties are affected by both water saturation coe

Coal mechanical behaviourDiscrete element methodNuclear magnetic resonance imagingAter distribution modelAterweakening effect

Stress-dilatancy behaviour of fouled ballast: experiments and DEM mode by Jing Chen, Buddhima Indraratna et al

This paper presents a study of the mechanical behaviour of ballast contaminated by different fouling agents such as coal and subgrade clay. Large-scale direct shear tests were carried out to examine the strength and deformation properties for coal-fouled and clay-fouled ballast. The experimental results show that fouled ballast (both clay and coal) exhibits a lower peak shear strength and decreased dilation during shearing. The clay-fouled ballast shows higher shear strength and smaller dilation compared to coal-fouled ballast. The relationship between shear stress and dilatancy of ballast under different fouling conditions is reported in this paper, where the numerical predictions are made using the discrete element method (DEM). The DEM simulations show that with the increase of fouling level, the coordination number, the average contact force, the particle rotation and the velocity decrease for ballast aggregates. The results indicate that coal-fouled ballast exhibits a smaller aver

Clay finesDirect shear testDiscrete element methodTress dilatancy relationship

MODELLING SUBGRADE FLUIDISATION UNDER RAIL TRACKS BASED ON LBM-DEM COU by Minh Nghi Phan

MODELLING SUBGRADE FLUIDISATION UNDER RAIL TRACKS BASED ON LBM-DEM COU by Minh Nghi Phan
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Lattice boltzmann methodDiscrete element methodComputational fluid dynamics

Nuclear power, nuclear accidents meltdown, radiation risks | Homeland Security Newswire

Nuclear power, nuclear accidents meltdown, radiation risks | Homeland Security Newswire
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United statesJean ragusaNuclear technologyMauricio eduardo tano retamalesNuclear engineeringComputational fluid dynamicsDiscrete element method studyBypass flowsPebble bed reactorDiscrete element methodஒன்றுபட்டது மாநிலங்களில்அணு தொழில்நுட்பம்அணு பொறியியல்கணக்கீட்டு திரவம் இயக்கவியல்கூழாங்கல் படுக்கை ரியாக்டர்தனித்தனி உறுப்பு முறை