Investigation of Air Damping of Cicular and Rectangular Plates, a Cylinder, and a Sphere

reportActive / Technical Report | Accession Number: ADA393838 | Open PDF

Abstract:

An investigation was conducted to determine the mechanism of air damping exhibited by rigid bodies of different shapes oscillating in a pressure environment. Circular and rectangular plates, as well as a sphere and cylinder, were attached to cantilever springs and the free decay of an induced oscillation was measured at pressure levels from atmospheric to k x 10-2 torr. Data are presented to show the effect of pressure, vibratory amplitude, frequency, shape, and surface area on the air damping of the models. Results indicate that the magnitude of the air damping may greatly exceed the structural damping of the system. The air damping associated with the plates is directly proportional to the pressure and amplitude and is indicative of dissipative loads proportional to the dynamic pressure. Furthermore, the plate damping was found to be independent of shape and is a nonlinear function of the surface area. The sphere and cylinder exhibit viscous damping characteristics which are in good agreement with available theory.

Author(s):
Stephens, David G. ; Scavullo, Maurice A.
Author Organization(s):
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION HAMPTON VA LANGLEY RESEARCH CENTER
Pagination:
0024

Security Markings

DOCUMENT & CONTEXTUAL SUMMARY

Distribution:
Approved For Public Release

RECORD

Collection: TR
Identifying Numbers
Report Number(s):
NASA-TN-D-1865
Monitor Series:
NASA
 Subject Terms
Joint Capability Areas:
JCA_1_Force Support; JCA_1.2_Force Preparation; JCA_3.2_Engagement; JCA_3_Force Application; JCA_1.3_Human Capital Management; JCA_3.2.1_Kinetic Means; JCA_6_Net Centric; JCA_1.3.2_Personnel Management; JCA_5_Command and Control
Communities of Interest:
Ground and Sea Platforms
Descriptor(s):
*STRUCTURAL PROPERTIES, *DAMPING, *SPHERES, *RECTANGULAR BODIES, *CIRCULAR, VIBRATION, ENVIRONMENTS, AIR, NONLINEAR ANALYSIS, AMPLITUDE, OSCILLATION, VISCOSITY, RIGIDITY, DYNAMIC PRESSURE, CANTILEVER BEAMS, APPARENT DENSITY
Field(s)/Group(s):
Theoretical Mathematics, Structural Engineering and Building Technology
Keyword(s):
AMPTIAC COLLECTION, *RECTANGULAR PLATES
Report Date:
1965 Apr 01
Creation Date:
2001 Sep 26