scholarly journals Theoretical description of laser melt pool dynamics, Task order number B239634, Quarter 3 report

1995 ◽  
Author(s):  
A. Dykhne
Keyword(s):  
Theoretical Description ◽  
Order Number ◽  
Melt Pool ◽  
Task Order

Potential Task Order Effects in Computer Test Batteries (Summary)

1997 ◽  
Author(s):  
Mark Czarnolewski ◽  
John Eliot ◽  
Jennifer Rinehart
Keyword(s):  
Order Effects ◽  
Task Order

Analysis of shear bands in slow granular flows using a frictional Cosserat model

2000 ◽  
Vol 627 ◽  
Author(s):  
Prabhu R. Nott ◽  
K. Kesava Rao ◽  
L. Srinivasa Mohan
Keyword(s):  
Scaling Laws ◽  
Shear Bands ◽  
Shear Layers ◽  
Theoretical Description ◽  
Field Variable ◽  
Cosserat Continuum ◽  
Momentum Balance ◽  
Rigid Plastic ◽  
Independent Field ◽  
Cosserat Model

ABSTRACTThe slow flow of granular materials is often marked by the existence of narrow shear layers, adjacent to large regions that suffer little or no deformation. This behaviour, in the regime where shear stress is generated primarily by the frictional interactions between grains, has so far eluded theoretical description. In this paper, we present a rigid-plastic frictional Cosserat model that captures thin shear layers by incorporating a microscopic length scale. We treat the granular medium as a Cosserat continuum, which allows the existence of localised couple stresses and, therefore, the possibility of an asymmetric stress tensor. In addition, the local rotation is an independent field variable and is not necessarily equal to the vorticity. The angular momentum balance, which is implicitly satisfied for a classical continuum, must now be solved in conjunction with the linear momentum balances. We extend the critical state model, used in soil plasticity, for a Cosserat continuum and obtain predictions for flow in plane and cylindrical Couette devices. The velocity profile predicted by our model is in qualitative agreement with available experimental data. In addition, our model can predict scaling laws for the shear layer thickness as a function of the Couette gap, which must be verified in future experiments. Most significantly, our model can determine the velocity field in viscometric flows, which classical plasticity-based model cannot.

Set-Theoretical Description of the System for Control of the State of Technical Information Protection

2005 ◽  
Vol 64 (3) ◽  
pp. 227-237
Author(s):  
A. V. Zhizhelev ◽  
S. V. Zhilinskii ◽  
A. V. Klyshevskii ◽  
S. A. Golovin
Keyword(s):  
Technical Information ◽  
Theoretical Description ◽  
The State ◽  
Information Protection
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