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....

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...

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...

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...

Dangerous Goods Emergency Response?The Western Australian Experience
A general overview of the State of Western Australia including: the legal framework of the Dangerous Goods and Emergency response management scenarios; particular problems unique to the...

Developing High-Risk Scenarios and Countermeasure Ideas for Mitigation of Hazardous Materials Incidents
Kansas State University (KSU) conducted a comprehensive study of the development of a set of prioritized, extreme-risk scenarios, the development of a set of feasible, practical and implementable...

Hazardous Materials Data: A Federal Perspective
This paper discusses the evolution and current status of the Hazardous Materials Incident Report System (HMIRS) maintained by the Research and Special Programs Administration (RSPA) of...

Issues in Developing Arizona's Hazmat Incident Reporting Program
The Arizona Division of Emergency Services (ADES), in cooperation with Arizona State University (ASU) - Center for Advanced Research in Transportation, and the Arizona Department of Transportation...

 

 

 

 

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