Instability and Plastic Flow of Soils
Materials should according to Drucker's postulate become unstable when the second increment of plastic work is negative. Experimental observations however show otherwise....
Modeling of Successive Impacts in Sand
The principal aspects of numerical modeling of successive, high energy impacts in sand are discussed in this paper. These include the numerical formulation used for solution of the equations...
A Micromechanics Model for Rough Interfaces
A new constitutive model for transfer of interfacial tractions along rough cracks in strain softening composites is presented. The model relates the normal and shearing stresses on the...
Comparison of a Microscopic Model and a Macroscopic Model Predictions on the Stress-Strain Behavior of a Soil
The stress-strain behavior of a soil under drained triaxial conditions was simulated using the Microscopic constitutive model TRUBAL. The model parameters for the Macroscopic constitutive...
Constitutive Relations for Granular Solids Accounting for Heterogeneous Deformation Fields
Under high deviatoric stress levels corresponding to large strains, the deformation of granular media is highly heterogeneous. A micro-mechanical approach is developed here to model the...
An Ellipse-based Micromechanical Model for Angular Granular Materials
An ellipse-based two-dimensional Discrete Element algorithm for numerically modeling angular granular materials is developed and presented. Interparticle contact computations require the...
Geometry of Yield Surfaces for Frictional Flow of Granular Materials
In the frictional flow regime, the discrete particles which compose of granular material roll or slide over one another, maintaining essentially continuous contact. Many theorists, including...
A Time-Dependent Microplane Model for Creep of Cohesive Soils
The microplane model is used in this paper to describe the time-dependent (creep) behavior of cohesive soils (clays). The constitutive equations are defined on each of a set of microplanes...
Numerical Undrained Cyclic Loading Simulations Using the Discrete Element Method
Three dimensional numerical experiments on random arrays of rough spheres were performed using the discrete element method to study the behavior of granular soil and the results were compared...
Numerical Experiments for Anisotropic Behavior of Granular Materials
A three dimensional discrete element computer code 'TRUBAL' is used to investigate the effect of initial anisotropy on stress-strain and volume change characteristics...
Instability in Granular Chute Flows
Numerical simulations showed that granular flows in a vertical chute can flow as a steady, uniform stream or as an intermittent slug flow. In numerical experiments slugs or grouping of...
Computer Simulations of Rapid Granular Flows Interacting with a Flat, Frictional Boundary
This paper compares the results of numerical simulations for the rapid, steady flow of identical spheres colliding with a flat frictional boundary with the recent predictions of Jenkins...
Simulations of Gravity-Driven Channel Flows of Disks Floating on the Flowing Viscous Fluid
A two-dimensional discrete element model has been applied to the problem of gravity-driven channel flow of uniform disks. The particles are floating on the surface of the flowing fluid...
Simulation of the Quasi-Static Deformation of 2D Assemblages of Rigid Discs
Although the importance of dilatancy in the constitutive behaviour of granular materials has been recognized for some time, conclusions about its evolution and dependence on different...
Numerical Simulation of Localization in Granular Materials
The structure of persistent shear bands in granular materials is investigated by numerically simulating an idealized assembly of two-dimensional particles. Flexible stress-controlled boundaries...
Interparticle Sliding and Rolling
Numerical experiments are done with a continuum plasticity program in order to study the initiation and evolution of shear bands. Many elements are used in order to resolve families of...
Pipeline Crossings
This proceedings of the Pipeline Crossings Conference, held on March 25-27, 1991 in Denver, Colorado, presents information on aspects of various pipeline crossings. It covers such broad...
Inspection Goes High Tech
Many believe that rehabilitation of the existing infrastructure�not net construction�will dominate the 1990s. Therefore, accurate condition assessment is crucial, since public works agencies...
Hurricane Retrofit
Houston's Sheraton Hotel and Convention Center has been retrofitted to protect it from panel pop-out (separation from building curtain walls) and curtain-wall separation from...
State Legislative Concerns Relative to Federal Hazardous Materials Transportation Regulation
States have increasingly asserted their authority to regulate hazardous materials transportation, in the face of inadequate and declining federal efforts. Areas of state interest include...
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