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Mechanics of Granular Materials (MGM)The constitutive behavior of uncemented granular materials such as strength, stiffness, and localization of deformations are to a large extend derived from interparticle friction transmitted between solid particles and particle groups. Interparticle forces are highly dependent on gravitational body forces. At very low effective confining pressures, the true nature of the Mohr envelope, which defines the Mohr-Coulomb failure criterion for soils, as well as the relative contribution of each of non-frictional components to soil's shear strength cannot be evaluated in terrestrial laboratories. Because of the impossibility of eliminating gravitational body forces on earth, the weight of soil grains develops interparticle compressive stresses which mask true soil constitutive behavior even in the smallest samples of models. Therefore the microgravity environment induced by near-earth orbits of spacecraft provides unique experimental opportunities for testing theories related to the mechanical behavior of terrestrial granular materials. Such materials may include cohesionless soils, industrial powders, crushed coal, etc. This paper will describe the microgravity experiment, 'Mechanics of Granular Materials (MGM)', scheduled to be flown on Space Shuttle-MIR missions. The paper will describe the experiment's hardware, instrumentation, specimen preparation procedures, testing procedures in flight, as well as a brief summary of the post-mission analysis. It is expected that the experimental results will significantly improve the understanding of the behavior of granular materials under very low effective stress levels.
Document ID
19970022141
Acquisition Source
Marshall Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Alshibli, Khalid A.
(Colorado Univ. Boulder, CO United States)
Costes, Nicholas C.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Porter, Ronald F.
(NASA Marshall Space Flight Center Huntsville, AL United States)
Date Acquired
September 6, 2013
Publication Date
August 5, 1996
Publication Information
Publication: SPIE Proceedings Series
Publisher: Society of Photo-Optical Instrumentation Engineers
Volume: 2809
ISBN: 0-8194-2197-9
Subject Category
Materials Processing
Report/Patent Number
NAS 1.26:204613
NASA-CR-204613
Meeting Information
Meeting: Space Processing Materials
Location: Denver, CO
Country: United States
Start Date: August 4, 1996
End Date: August 5, 1996
Sponsors: International Society for Optical Engineering
Accession Number
97N22745
Funding Number(s)
CONTRACT_GRANT: NAS8-38779
Distribution Limits
Public
Copyright
Public Use Permitted.
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