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Influence of Temperature and Impact Velocity on the Coefficient of RestitutionTests were performed on a variety of material combinations to understand the effects of temperature and impact velocity on the coefficient of restitution (COR). The tests, performed in a vacuum at room and liquid nitrogen temperatures, consisted of dropping a ball onto a target plate and recording the impact time history of the ball's bounce-down. Time intervals between successive impacts were measured from the time history and used to calculate the coefficient of restitution and impact velocity for each impact. Maximum impact velocities ranged from approximately 33 (0.84) to 52 in./s (1.32 m/s). Five ball-target plate combinations were evaluated: type 316 stainless steel (316 SS) on 316 SS; M50 tool steel on Armalon; M50 on 4340 steel; 410C steel on Armalon; and copper on copper. The coefficient of restitution for the 316 SS-316 SS, M50-Armalon, 410C-Armalon, and copper-copper combinations increased as the temperature and impact velocity decreased. The coefficient for the hard steel combination, M50-4340, was not greatly influenced by temperature or variations in impact velocity.
Document ID
Document Type
Technical Memorandum (TM)
Radil, Kevin C.
(NASA Lewis Research Center Cleveland, OH, United States)
Palazzolo, Alan B.
(NASA Lewis Research Center Cleveland, OH, United States)
Date Acquired
September 6, 2013
Publication Date
July 1, 1994
Subject Category
Mechanical Engineering
Report/Patent Number
NAS 1.15:106485
Funding Number(s)
PROJECT: DA PROJ. 1L1-61102-AH-45
Distribution Limits
Work of the US Gov. Public Use Permitted.

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