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Proceedings Paper

Three-degree-of-freedom adaptive-passive isolator for launch vehicle payloads
Author(s): Farshad Khorrami; Jahangir S. Rastegar; R. Scott Erwin
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Paper Abstract

Payloads are attached to launch vehicles by structural adapters known as Payload Adapter Fittings (PAF). The adapters are substantially rigid; therefore, the launch vehicle vibration is transmitted without isolation to the payloads. The payload cost includes a substantial component for provision to withstand the severe launch vibration environment. In this paper, a novel three degree-of-freedom isolation system built in the footprint and within the existing PAFs is presented. The vibration isolator consists of a mechanical constraining mechanism that prevents the rotation of the payload relative to the launch vehicle in both rocking rotation and rotation about the long axis of the launch vehicle. The above rotational motion restraining mechanism would therefore only allow axial and lateral vibration of the payload relative to the launch vehicle. The second major component of the system consists of isolation components that are used to reduce vibration in the latter to directions, i.e., in the axial and the lateral directions. The proposed isolating payload adapter fitting also has a stand-alone thrust-support preload adjustment component that adjusts for the varying quasi-static acceleration seen in different flight regimes in a passive- adaptive control mode. The advocated isolation system is structurally modular and parameterizable such that a range of launch vehicle platforms could be accommodated. Through the utilization of the advocated isolating payload adapter fitting, a fifty percent reduction in vibration transmission is achieved at 10 Hz in the axial direction and 20 Hz in the lateral directions. A 40 db reduction is achieved at frequencies above 100 Hz. Active actuating elements may easily be included in the prosed design to attain an active isolation unit.

Paper Details

Date Published: 12 June 2000
PDF: 12 pages
Proc. SPIE 3991, Smart Structures and Materials 2000: Industrial and Commercial Applications of Smart Structures Technologies, (12 June 2000); doi: 10.1117/12.388158
Show Author Affiliations
Farshad Khorrami, OmniTek Research & Development, Inc. (United States)
Jahangir S. Rastegar, OmniTek Research & Development, Inc. (United States)
R. Scott Erwin, Air Force Research Lab. (United States)

Published in SPIE Proceedings Vol. 3991:
Smart Structures and Materials 2000: Industrial and Commercial Applications of Smart Structures Technologies
Jack H. Jacobs, Editor(s)

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