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作者 Lips, John Anthony
書名 Deployment rate prediction model for elastic memory composites
說明 252 p
附註 Source: Dissertation Abstracts International, Volume: 68-01, Section: B, page: 0475
Adviser: Arup K. Maji
Thesis (Ph.D.)--The University of New Mexico, 2007
The focus of this work is on the development of an analytic model to be used as a prediction tool for the deployment rate of Elastic Memory Composites (EMC). EMC's show promise as a structural material, which when subjected to a specific thermal cycle, are capable of providing their own inherent deployment actuation. This actuation produces a shape memory effect similar to that of other shape memory materials. However, the mechanics of this process are significantly different
EMC's combine a conventional fiber phase with a proprietary partially cross-linked thermoset epoxy resin phase. This resin phase softens with elevated temperature allowing for local deformations of the fibers within the matrix. These microbuckles are held captive within the polymer matrix as it is brought back to room temperature. Upon reheating the stored strain energy in these microbuckles is released enabling deployment
Two deployment variations were characterized experimentally and subsequently modeled. The ramped temperature deployment was controlled via a experimentally prescribed ambient linear temperature profile. This linear profile raised the temperature from 80 to 180°F over roughly eight minutes. The stowed specimen, which was previously bent into a 180° three inch diameter arc, was held fixed at one end while the other was free to deploy as the resin softened with temperature
The constant temperature deployment consisted of a specimen stowed in the same fashion, but restrained from deployment until the prescribed temperature was obtained throughout the specimen. At this point, the constraint was rapidly released allowing the specimen to deploy. These constant temperature deployments were conducted at 110, 130, 150, and 170°F. The rate of deployment and the degree of angular recovery increased dramatically with temperature
The controlling phenomenon behind the deployment rate of this EMC is the viscoelastic character of the polymer resin phase. An experimental characterization of the creep behavior of this polymer matrix was performed at sample temperatures from 80 to 175°F. Toward this end, a number of strain and load measurement devices were evaluated for their suitability to this demanding type of experiment
School code: 0142
Host Item Dissertation Abstracts International 68-01B
主題 Engineering, Civil
Alt Author The University of New Mexico
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