Download or read book The Material Point Modeling of Granular Flow in a Silo written by Zdzislaw Wiȩckowski and published by . This book was released on 2006 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Confined Granular Flow in Silos written by Jacek Tejchman and published by Springer Science & Business Media. This book was released on 2013-05-15 with total page 503 pages. Available in PDF, EPUB and Kindle. Book excerpt: During confined flow of bulk solids in silos some characteristic phenomena can be created, such as: sudden and significant increase of wall stresses, different flow patterns, formation and propagation of wall and interior shear zones, fluctuation of pressures and, strong autogenous dynamic effects. These phenomena have not been described or explained in detail yet. The main intention of the experimental and theoretical research presented in this book is to explain the above mentioned phenomena in granular bulk solids and to describe them with numerical FE models verified by experimental results.
Download or read book A Nonlocal Dense Granular Flow Model Implemented in the Material Point Method written by Sachith Anurudde Dunatunga and published by . This book was released on 2014 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: A nonlocal model for dense granular flow is implemented in the material point method (MPM), an extension of the finite element method (FEM) for solid mechanics. The nonlocal model used has shown great predictive capability for dense flows when implemented in the finite element framework, but limitations of FEM prevent application of the model to truly large scale, inhomogeneous deformations. We show that these FEM results may be replicated in the MPM framework through the solution of a vertical chute flow, and allows for future work utilizing the strengths of MPM for larger and more complex flows.
Download or read book Discrete Dynamic Modelling of Granular Flows in Silos written by Michael G. Remias and published by . This book was released on 1998 with total page 150 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis develops and tests a two-dimensional discrete dynamic model for the simulation of granular flows in silos and hoppers. The granular material considered is assumed to be an assembly of viscoelastic discs and the motion of such a particle system is shown to be governed by a set of nonlinear first order ordinary differential equations. This system of equations is then solved numerically using the centered finite difference scheme. Based on the model presented, a computer program has been developed and used to analyse the flow behaviour of granular materials during filling and emptying of a silo. The results show that the discrete dynamic model developed is capable of modelling granular flows in silos, particularly predicting wall pressures and analysing flow blockage.
Download or read book Simulation of Granular Flows with the Material Point Method written by Philip Alsop and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The primary objective of this thesis is to investigate the particle and pressure distribution of granular transitional flows using the Material Point Method (MPM). Additionally, the role of the fluid phase in submerged flows will be examined in the granular column collapse problem. Simulations of dry granular column collapse are carried out and compared to existing experimental and simulation references on the basis of runout distance and total collapse time. Model and material parameters are calibrated to match 2D plane-strain experiments of granular column collapse performed at Uniandes. A novel two phase two point fully coupled MPM formulation is developed considering an incompressible fluid phase, that allows for soil-water and free-water interactions with free-surface effects.
Download or read book Granular Flow Models Analysis and Numerical Simulations written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We study elastoplastic transitions in solutions of the antiplane shear model of granular flow, and describe a time-periodic solution that arises when the antiplane shear model is discretized in space. The antiplane shear model is a simplification of the continuum equations representing the flow of granular materials. The modeling of granular flow has many applications, from agricultural silos to geomechanics: improved accuracy in modeling will lead to safer and more economical designs for silos and industrial hoppers, and make oil drilling a more efficient process. We construct approximate solutions to the antiplane shear model with piecewise linear initial data, which feature transitions between elastic and plastic states. These transitions travel with fixed speed. Numerical simulations demonstrate that the same elastoplastic transitions are the prominent features of the numerical solution. The periodic solution of discretized antiplane shear appears at a critical value of the elasticity parameter for antiplane shear. The bifurcation to a periodic solution appears to be a Hopf bifurcation. The periodic solution contains elastoplastic transitions, as well as a shear band that appears over part of the period. Away from the shear band, the periodic solution has four distinct regions, three elastic and one plastic. Refinement of the spatial discretization further resolves these states.
Download or read book Computer Simulations for a Scholastic Theory of Granular Drainage written by Richard Camilo Guáqueta and published by . This book was released on 2003 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Optical Coherence Tomography in Cardiovascular Research written by Evelyn Regar and published by CRC Press. This book was released on 2007-03-06 with total page 776 pages. Available in PDF, EPUB and Kindle. Book excerpt: Given that for centuries, the standard tool to understand diseases in tissues was the microscope and that its major limitation was that only excised tissue could be used, recent technology now permits the examination of diseased tissue in vivo. Optical coherence tomography (OCT) has promising potential when applied to coronary artery disease. OCT has the capability to identify coronary plaque and to distinguish between plaques that are stable and unstable. If the plaques are stable then OCT can direct percutaneous intervention (angioplasty or stenting). Optical coherence tomography is a light-based imaging technology that allows for very high resolution imaging in biological tissues. It has been first applied in ophthalmology, where it soon became the golden standard for the assessment of (epi-) retinal processes. The unique imaging capabilities have raised the interest of researchers and clinicians in the field of cardiovascular disease, since OCT offers unique possibilities to study atherosclerosis pathophysiology in vivo. With over 1.1M Americans having a heart attack this year because of unstable plaque rupture, OCT may have an increasingly important role in the early diagnosis of coronary artery disease. This unique publication offers the reader the basic background to OCT and its role in the diagnosis and management of coronary artery disease. The Handbook of Optical Coherence Tomography in Cardiovascular Research introduces the cardiovascular application of this technology. Clinicians, biologists, engineers and physicist are discussing different aspects of cardiovascular OCT application in a multidisciplinary approach. The handbook offers the readership a concise overview on the current state of the art of vascular OCT imaging and sheds light on a variety of exciting new developments. The physics, technical principles of OCT and its application in a broad spectrum of cardiovascular research areas are summarized by highly recognized specialists. The potential of OCT in peripheral and coronary arteries and in developmental cardiology are described. Each research area is introduced by a clinical expert in the field followed by discussion of different aspects from an engineering, biomedical and clinical perspective. Specifically, the current capabilities for plaque characterization, detection of vulnerable plaque, guidance of interventional procedures, Doppler-assessment, and molecular contrast imaging are being described. The Handbook of Optical Coherence Tomography in Cardiovascular Research targets researchers and clinicians involved in the field of atherosclerosis. The summary of basic physics, engineering solutions, pre-clinical and clinical application covers all relevant aspects and will be a valuable reference source.
Download or read book Small strain Stiffness of Soils and Its Numerical Consequences written by Thomas Benz and published by . This book was released on 2007 with total page 187 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Powders and Grains 2005 Two Volume Set written by R. Garcia-Rojo and published by CRC Press. This book was released on 2005-07-01 with total page 1510 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the proceedings of the Fifth International Conference on the Micromechanics of Granular Media, Powders and Grains 2005. Powders and Grains is an international scientific conference held every 4 years that brings together engineers and physicists interested in the micromechanics of granular media.The book is a guide to the hotte
Download or read book Advances in Applied Mechanics written by Stéphane P.A. Bordas and published by Academic Press. This book was released on 2021-11-23 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Applied Mechanics, Volume 54 in this ongoing series, highlights new advances in the field, with this new volume presenting interesting chapters on Advanced geometry representations and tools for microstructural and multiscale modelling, Material Point Method: overview and challenges ahead, From Experimental Modeling of Shotcrete to Numerical Simulations of Tunneling, Mechanics of Hydrogel-Based Bioprinting: From 3D to 4D, and more. - Provides the authority and expertise of leading contributors from an international board of authors - Presents the latest release in the Advances in Applied Mechanics series
Download or read book The Mechanics and Thermodynamics of Continua written by Morton E. Gurtin and published by Cambridge University Press. This book was released on 2010-04-19 with total page 721 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Mechanics and Thermodynamics of Continua presents a unified treatment of continuum mechanics and thermodynamics that emphasises the universal status of the basic balances and the entropy imbalance. These laws are viewed as fundamental building blocks on which to frame theories of material behaviour. As a valuable reference source, this book presents a detailed and complete treatment of continuum mechanics and thermodynamics for graduates and advanced undergraduates in engineering, physics and mathematics. The chapters on plasticity discuss the standard isotropic theories and, in addition, crystal plasticity and gradient plasticity.
Download or read book A Framework for Continuum Simulation of Granular Flow written by Sachith Anurudde Dunatunga and published by . This book was released on 2017 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Granular materials have eluded continuum modeling attempts for centuries. A significant chunk of the complexity lies in the trans-phase behavior of granular media; while the material has a yield stress and can therefore act as a solid body, grains may also flow quickly much like a liquid. At low pressures and high velocities, the grains may even become disconnected from each other, resulting in a gas-like state where the only stresses are essentially due to occasional collisions between grains. Moreover, all three states are commonly found simultaneously in many industrial and natural processes, and individual grains may switch between these phases readily. A further complication is that typically the grain size is large compared to the geometries in which we are interested; these size effects can lead to mispredictions when purely local models (without an intrinsic length scale) are used. Due to these complexities, a highly favored technique is the discrete element method, which tracks each grain individually and updates the forces and displacements when grains contact each other. While extremely accurate, discrete methods require incredible amounts of computational power, severely restricting the sizes of problems that can be simulated. Continuum techniques can potentially scale better, as individual grain-grain interactions are no longer tracked, but require a constitutive model. Recent continuum models, such as in Jop, Forterre, and Pouliquen (2006) and Kamrin and Koval (2012) show promise in capturing many observed phenomena, yet current numerical techniques limit the applicability of these models due to computational or numerical issues. In this thesis, we explore a continuum framework for simulation of granular materials in the context of the material point method, which allows us to test these material models further than many existing continuum techniques and pave the way for efficient simulation of large-scale processes involving granular media.
Download or read book Simulation of Granular Media with the Material Point Method written by Gergely Klar and published by . This book was released on 2016 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: We propose an extension to the Material Point Method for the simulation of granular media. We model the dynamics with an elastoplastic, continuum assumption. The behavior of the granular media is captured by the Drucker-Prager yield criterion that naturally represents the frictional relationship between shear and normal stresses. We develop a stress projection algorithm that is well suited for both explicit and implicit time integration, and uses a non-associative flow rule to ensure volume preservation. Our approach is able to recreate the dynamics of granular media undergoing large deformations, topological changes, and collisions.
Download or read book Powders and Bulk Solids written by Dietmar Schulze and published by Springer Nature. This book was released on 2021-09-02 with total page 625 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book concentrates on powder flow properties, their measurement and applications. These topics are explained starting from the interactions between individual particles up to the design of silos. A wide range of problems are discussed – such as flow obstructions, segregation, and vibrations. The goal is to provide a deeper understanding of the powder flow, and to show practical solutions.
Download or read book Traffic and Granular Flow 07 written by Cécile Appert-Rolland and published by Springer Science & Business Media. This book was released on 2009-05-19 with total page 758 pages. Available in PDF, EPUB and Kindle. Book excerpt: Covers several research fields dealing with transport. This work covers three main topics including road traffic, granular matter, and biological transport. It considers different points of views including modelling, simulations, experiments, and phenomenological observations.
Download or read book A Fully Implicit Particle in cell Method for Granular Flows written by and published by . This book was released on 2001 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wide variety of numerical models have been used to capture the complexities of granular flow. Examples include Monte Carlo models, lattice gas models and numerical models to resolve the grains. The latter is the subject of this paper. In particular, an implicit formulation of the material point method (MPM) is considered in the modeling of granular materials. MPM combines a Lagrangian treatment, using material points, with an Eulerian grid. These material points describe the grain dynamics, they resolve edges and allow history dependent effects to be recorded. The Eulerian grid allows for efficient computation of interactions between grains. Contacts between grains are computed with a model based on the immersed boundary method; interpenetration is prevented but grain separation, sliding and bonding are allowed. Previous versions of the MPM algorithm advance the solution in time using a leapfrog algorithm. These work well for relatively high strain rates but implicit methods have the potential to be more robust, stable and efficient for low strain rate calculations. In this paper, a Newton-Krylov (NK) algorithm is applied to the solution of the implicit MPM equations. The implementation is matrix-free, requiring only the evaluation of the residual error at each iterative step - ideal in the solution of the non-linear and non-analytic implicit MPM formulation. In this paper, the granular flow model is presented and the implicit MPM formulation described. Next, the implementation of the Newton-Krylov technique is discussed and the results of numerical experiments for a single grain and an assembly of compressed grains presented. An implicit-in-time method for granular materials is described. The method combines the Material Point Method (MPM), and a Newton-Krylov equation solver to give improved energy conservation and stabilization.
