3d Multi Scale Behavior Of Granular Materials Using Experimental And Numerical Techniques PDF Download
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Author | : Andrew Druckrey |
Publisher | : |
Total Pages | : 335 |
Release | : 2016 |
Genre | : Granular materials |
ISBN | : |
Download 3D Multi-scale Behavior of Granular Materials Using Experimental and Numerical Techniques Book in PDF, ePub and Kindle
Constitutive modeling of granular material behavior has generally been based on global response of laboratory-size specimens or larger models with little understanding of the fundamental mechanics that drive the global response. Many studies have acknowledged the importance of micro-scale and meso-scale mechanics on the constitutive behavior of granular materials. However, much knowledge is still missing to develop and improve robust micromechanical constitutive models. The research in this dissertation contributes to this knowledge gap for many potential applications using novel experimental techniques to investigate the three-dimensional (3D) behavior of granular materials. Critical micromechanics measurements at multiple scales are investigated by combining 3D synchrotron micro-computed tomography (SMT), 3D image analysis, and finite element analysis (FEA). At the single particle level (micro-scale), particle fracture was examined at strain rates of 0.2 mm/min and 2 m/s using quasi-static unconfined compression, unconfined mini-Kolsky bar, and x-ray imaging techniques. Surface reconstructions of particles were generated and exported to Abaqus FEA software, where quasi-static and higher rate loading curves and crack propagation were simulated with good accuracy. Stress concentrations in oddly shaped particles during FEA simulations resulted in more realistic fracture stresses than theoretical models. A nonlinear multivariable statistical model was developed to predict force required to fracture individual particles with known internal structure and loading geometry. At the meso-scale, 3D SMT imaging during in-situ triaxial testing of granular materials were used to identify particle morphology, contacts, kinematics and interparticle behavior. Micro shear bands (MSB) were exposed during pre-peak stress using a new relative particle displacement concept developed in this dissertation. MSB for spherical particles (glass beads) had larger thickness (3d50 to 5d50) than that of angular sands (such as F35 Ottawa sand, MSB thickness of 1d50 to 3d50). Particle morphology also plays a significant role in the onset and growth of shear bands and global fabric evolution of granular materials. More spherical particles typically exhibit more homogeneous internal anisotropy. Fabric of particles within the shear band (at higher densities and confining pressures) exhibits a peak and decrease into steady-state. Also, experimental fabric produces more accurate strength and deformation predictions in constitutive models that incorporate fabric evolution.
Author | : Andrew J. Van Vooren |
Publisher | : |
Total Pages | : |
Release | : 2013 |
Genre | : Compacting |
ISBN | : |
Download A Multi-scale Approach to a Greater Understanding of the Behavior of Heterogeneous Materials Under Dynamic Loading Book in PDF, ePub and Kindle
The penetration of granular materials is of interest to a variety of different fields, and is an active area of research. The objective of this project is to gain understanding of the dynamics of a projectile penetrating into a granular material. To do this, experiments were run and a numerical model was created. A dart gun was used to accelerate an aluminum dart to velocities around 100 m/s, which then impacted a target tank filled with Ottawa sand. The dart flew along a view window, which allowed for a recording of the penetration event using a high speed camera. Pressure gauges inserted into the target tank measured the timing and magnitude of the compaction wave created by the dart. In these penetration events a two wave structure was discovered; a compaction wave and a fracture wave. The fracture wave is characterized by a white cone around the nose of the dart, which is created by increased reflectance from the newly created fracture surfaces in the grains of sand. An experiment was conducted in which single grain of sand was crushed. From this experiment it was discovered that the phenomenon that creates increased reflectivity is the creation of fractures faces in the sand, and is not triboluminescence. Stress-strain data for the sand was also gathered, to be used in the numerical simulation. An ultrasonic pulser/receiver was used to gather data on the longitudinal and shear wave sound speeds through "as poured" Ottawa sand; 263 m/s and 209 m/s respectively. It was determined that the compaction and damage wave speeds were not related to either the longitudinal or shear wave speeds. A numerical model was created using an EMU Peridynamic code. This code utilizes integral rather than differential equations, which allows for the modeling of crack propagation and fracture. The numerical simulations run were two-dimensional and on a smaller scale than the penetration experiments. The numerical simulation showed evidence of a compaction wave, force chain creation, and grain fracture, all of which were also observed in the penetration experiments.
Author | : Hans-Georg Matuttis |
Publisher | : John Wiley & Sons |
Total Pages | : 484 |
Release | : 2014-06-23 |
Genre | : Science |
ISBN | : 111856720X |
Download Understanding the Discrete Element Method Book in PDF, ePub and Kindle
Gives readers a more thorough understanding of DEM and equips researchers for independent work and an ability to judge methods related to simulation of polygonal particles Introduces DEM from the fundamental concepts (theoretical mechanics and solidstate physics), with 2D and 3D simulation methods for polygonal particles Provides the fundamentals of coding discrete element method (DEM) requiring little advance knowledge of granular matter or numerical simulation Highlights the numerical tricks and pitfalls that are usually only realized after years of experience, with relevant simple experiments as applications Presents a logical approach starting withthe mechanical and physical bases,followed by a description of the techniques and finally their applications Written by a key author presenting ideas on how to model the dynamics of angular particles using polygons and polyhedral Accompanying website includes MATLAB-Programs providing the simulation code for two-dimensional polygons Recommended for researchers and graduate students who deal with particle models in areas such as fluid dynamics, multi-body engineering, finite-element methods, the geosciences, and multi-scale physics.
Author | : Francois Nicot |
Publisher | : Elsevier |
Total Pages | : 388 |
Release | : 2017-11-20 |
Genre | : Technology & Engineering |
ISBN | : 0081025963 |
Download Advances in Multi-Physics and Multi-Scale Couplings in Geo-Environmental Mechanics Book in PDF, ePub and Kindle
Advances in Multi-Physics and Multi-Scale Couplings in Geo-Environmental Mechanics reunites some of the most recent work from the French research group MeGe GDR (National Research Group on Multiscale and Multiphysics Couplings in Geo-Environmental Mechanics) on the theme of multi-scale and multi-physics modeling of geomaterials, with a special focus on micromechanical aspects. Its offers readers a glimpse into the current state of scientific knowledge in the field, together with the most up-to-date tools and methods of analysis available. Each chapter represents a study with a different viewpoint, alternating between phenomenological/micro-mechanically enriched and purely micromechanical approaches. Throughout the book, contributing authors will highlight advances in geomaterials modeling, while also pointing out practical implications for engineers. Topics discussed include multi-scale modeling of cohesive-less geomaterials, including multi-physical processes, but also the effects of particle breakage, large deformations on the response of the material at the specimen scale and concrete materials, together with clays as cohesive geomaterials. The book concludes by looking at some engineering problems involving larger scales. Identifies contributions in the field of geomechanics Focuses on multi-scale linkages at small scales Presents numerical simulations by discrete elements and tools of homogenization or change of scale
Author | : Elena Ferretti |
Publisher | : Momentum Press |
Total Pages | : 282 |
Release | : 2014-02-02 |
Genre | : Technology & Engineering |
ISBN | : 1606506064 |
Download The Cell Method Book in PDF, ePub and Kindle
The Cell Method (CM) is a computational tool that maintains critical multidimensional attributes of physical phenomena in analysis. This information is neglected in the differential formulations of the classical approaches of finite element, boundary element, finite volume, and finite difference analysis, often leading to numerical instabilities and spurious results. This book highlights the central theoretical concepts of the CM that preserve a more accurate and precise representation of the geometric and topological features of variables for practical problem solving. Important applications occur in fields such as electromagnetics, electrodynamics, solid mechanics and fluids. CM addresses non-locality in continuum mechanics, an especially important circumstance in modeling heterogeneous materials. Professional engineers and scientists, as well as graduate students, are offered: • A general overview of physics and its mathematical descriptions; • Guidance on how to build direct, discrete formulations; • Coverage of the governing equations of the CM, including nonlocality; • Explanations of the use of Tonti diagrams; and • References for further reading.
Author | : Bernard Cambou |
Publisher | : Springer Science & Business Media |
Total Pages | : 416 |
Release | : 1998-08-12 |
Genre | : Science |
ISBN | : 9783211829202 |
Download Behaviour of Granular Materials Book in PDF, ePub and Kindle
This book presents a complete and comprehensive analysis of the behaviour of granular materials including the description of experimental results, the different ways to define the global behaviour from local phenomena at the particle scale, the various modellings which can be used for a D.E.M. analysis to solve practical problems and finally the analysis of strain localisation. The concepts developed in this book are applicable to many kinds of granular materials considered in civil, mechanical or chemical engineering.
Author | : Pasquale Giovine |
Publisher | : Springer Nature |
Total Pages | : 288 |
Release | : 2020-11-09 |
Genre | : Mathematics |
ISBN | : 3030492672 |
Download Views on Microstructures in Granular Materials Book in PDF, ePub and Kindle
This contributed volume provides an up-to-date overview of the mechanics of granular materials, ranging from sparse media to soils. With chapters exploring state-of-the-art theoretical, experimental, and applied trends in the study of granular matter in various states, readers will be motivated to learn about the current challenges and potential avenues of exploration in this active area of research. Including a variety of perspectives, this volume will be a valuable reference for audiences in a number of fields. Specific topics covered include: X-ray tomography techniques for analyzing sand Evaluation of effective stress in unsaturated soils Hyper-plasticity Wave propagation in granular systems Partly saturated porous media Multi-scale approaches to the dynamics of sparse media Views on Microstructures in Granular Materials is an ideal resource for PhD students and researchers in applied mathematics, solid-state physics, civil engineering, and mechanical engineering.
Author | : Bernard Cambou |
Publisher | : Elsevier |
Total Pages | : 198 |
Release | : 2016-08-19 |
Genre | : Technology & Engineering |
ISBN | : 008101077X |
Download Granular Materials at Meso-scale Book in PDF, ePub and Kindle
Granular Materials at Meso-scale: Towards a Change of Scale Approach proposes a new way for developing an efficient change of scale—considering a meso-scale defined at the level of local arrays of particles. The change of scale is known to be a very interesting way to improve the modelling of mechanical behavior granular materials. In the past, studies have been proposed using a micro-scale at the grain level to perform change of scale, but limitations have been proven for these approaches. Definition and analysis of the phases are detailed, constituted by sets of meso-domains sharing the same texture characteristics. The authors propose a local constitutive model for the phases, allowing the constitutive model of the representative elementary volume to be definied from a change-of-scale approach and, finally, presenting the validation of obtained modeling on cyclic loadings. Proposes a new way for developing an efficient change of scale—considering a meso-scale Explores local meso-domains and texture characteristics Defines meso-strain and stress Analyzes the evolution of these variables and texture characteristics in relation to the applied loading
Author | : Jagan Mohan Padbidri |
Publisher | : |
Total Pages | : 73 |
Release | : 2010 |
Genre | : Granular materials |
ISBN | : |
Download A Network-cell Based Framework for Multiscale Analysis of Granular Materials Book in PDF, ePub and Kindle
Author | : Mohamed Jebahi |
Publisher | : John Wiley & Sons |
Total Pages | : 196 |
Release | : 2015-03-30 |
Genre | : Technology & Engineering |
ISBN | : 1848217706 |
Download Discrete Element Method to Model 3D Continuous Materials Book in PDF, ePub and Kindle
Complex behavior models (plasticity, cracks, visco elascticity) face some theoretical difficulties for the determination of the behavior law at the continuous scale. When homogenization fails to give the right behavior law, a solution is to simulate the material at a meso scale in order to simulate directly a set of discrete properties that are responsible of the macroscopic behavior. The discrete element model has been developed for granular material. The proposed set shows how this method is capable to solve the problem of complex behavior that are linked to discrete meso scale effects.