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A Micromechanics Finite Element Model for Studying the Mechanical Behavior of Spray-On Foam Insulation (SOFI)A micromechanics model has been constructed to study the mechanical behavior of spray-on foam insulation (SOFI) for the external tank. The model was constructed using finite elements representing the fundamental repeating unit of the SOFI microstructure. The details of the micromechanics model were based on cell observations and measured average cell dimensions discerned from photomicrographs. The unit cell model is an elongated Kelvin model (fourteen-sided polyhedron with 8 hexagonal and six quadrilateral faces), which will pack to a 100% density. The cell faces and cell edges are modeled using three-dimensional 20-node brick elements. Only one-eighth of the cell is modeled due to symmetry. By exercising the model and correlating the results with the macro-mechanical foam behavior obtained through material characterization testing, the intrinsic stiffness and Poisson s Ratio of the polymeric cell walls and edges are determined as a function of temperature. The model is then exercised to study the unique and complex temperature-dependent mechanical behavior as well as the fracture initiation and propagation at the microscopic unit cell level.
Document ID
20070007333
Acquisition Source
Glenn Research Center
Document Type
Conference Paper
Authors
Ghosn, Louis J.
(Ohio Aerospace Inst. Brook Park, OH, United States)
Sullivan, Roy M.
(NASA Glenn Research Center Cleveland, OH, United States)
Lerch, Bradley A.
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
August 24, 2013
Publication Date
January 1, 2006
Subject Category
Spacecraft Design, Testing And Performance
Meeting Information
Meeting: 43rd Annual Technical Meeting of the Society of Engineering Science
Location: PA
Country: United States
Start Date: August 13, 2006
End Date: August 16, 2006
Sponsors: Society of Engineering Science
Funding Number(s)
WBS: WBS 524238.08.02.03.04
Distribution Limits
Public
Copyright
Public Use Permitted.
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