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An Experimental Investigation of Silicone-to-Metal Bond Strength in Composite Space Docking System SealsThe National Aeronautics and Space Administration (NASA) is currently developing a new universal docking mechanism for future space exploration missions called the Low Impact Docking System (LIDS). A candidate LIDS main interface seal design is a composite assembly of silicone elastomer seals vacuum molded into grooves in an electroless nickel plated aluminum retainer. The strength of the silicone-tometal bond is a critical consideration for the new system, especially due to the presence of small areas of disbond created during the molding process. In the work presented herein, seal-to-retainer bonds of subscale seal specimens with different sizes of intentional disbond were destructively tensile tested. Nominal specimens without intentional disbonds were also tested. Tension was applied either uniformly on the entire seal circumference or locally in one short circumferential length. Bond failure due to uniform tension produced a wide scatter of observable failure modes and measured load-displacement behaviors. Although the preferable failure mode for the seal-to-retainer bond is cohesive failure of the elastomer material, the dominant observed failure mode under the uniform loading condition was found to be the less desirable adhesive failure of the bond in question. The uniform tension case results did not show a correlation between disbond size and bond strength. Localized tension was found to produce failure either as immediate tearing of the elastomer material outside the bond region or as complete peel-out of the seal in one piece. The obtained results represent a valuable benchmark for comparison in the future between adhesion loads under various separation conditions and composite seal bond strength.
Document ID
20100039315
Document Type
Contractor Report (CR)
Authors
Gaier, James R. (NASA Glenn Research Center Cleveland, OH, United States)
Siamidis, John (NASA Glenn Research Center Cleveland, OH, United States)
Larkin, Elizabeth M. G. (Case Western Reserve Univ. Cleveland, OH, United States)
Date Acquired
August 25, 2013
Publication Date
October 1, 2010
Subject Category
Composite Materials
Report/Patent Number
E-17465
NASA/CR-2010-216886
AIAA Paper 2009-5318
Meeting Information
25th Space Simulation Conference(Annapolis, MD)
Funding Number(s)
WBS: WBS 936374.04.08.03
CONTRACT_GRANT: NNX08AU01H
CONTRACT_GRANT: NNC08CA35C
Distribution Limits
Public
Copyright
Public Use Permitted.

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