VORTEX SHEDDING MITIGATION METHODS

Award Information
Agency:
Department of Defense
Branch
Army
Amount:
$49,927.00
Award Year:
1991
Program:
SBIR
Phase:
Phase I
Contract:
n/a
Award Id:
15770
Agency Tracking Number:
15770
Solicitation Year:
n/a
Solicitation Topic Code:
n/a
Solicitation Number:
n/a
Small Business Information
Po Box 5031, Monrovia, CA, 91017
Hubzone Owned:
N
Minority Owned:
N
Woman Owned:
N
Duns:
n/a
Principal Investigator:
Dr P B S Lissaman
Principal Investigator
(818) 357-9983
Business Contact:
() -
Research Institute:
n/a
Abstract
THERE IS A REQUIREMENT FOR EFFECTIVE METHODS TO MITIGATE WIND INDUCED VIBRATION IN ANTENNA STRUCTURES. THESE VIBRATIONS CAUSE DISTORTION IN THE SIGNAL. CURRENT ANTENNA STRUCTURES ARE CONSTRUCTED FROM FRP TUBING BECAUSE OF ITS BENIGN ELECTROMAGNETIC PROPERTIES BUT THE MATERIAL, BECAUSE OF ITS LOW STIFFNESS AND DAMPING PROPERTIES, AGGRAVATES WIND-INDUCED VIBRATIONS. THE VIBRATIONS ARE CAUSED BY EITHER KARMAN VORTEX SHEDDING FROM THE INDIVIDUAL TUBES IN THE STRUCTURE, OR BY THE GUST RESPONSE CHARACTERISTICS OF THE STRUCTURE AS A WHOLE. A FOUR TASK PROGRAM IS OUTLINES IN WHICH BOTH OF THESE FORCING FUNCTIONS AND THEIR EFFECTS, IN TERMS OF THE SEVERITY OF VIBRATION THEY CAUSE IN THE ANTENNA, ARE TO BE INVESTIGATED. THIS WILL BE ACCOMPLISHED THROUGH A MODEL ANALYSIS OF THE ANTENNA STRUCTURE IN QUESTION BY UTILIZING FINITE ELEMENT METHODS. METHODS FOR SPOILING THE FORMATION OF THE SHED KARMAN VORTICES AS WELL AS CHANGING THE COMPLIANCY OF THE STRUCTURE AND ADDING VARIOUS DAMPING SYSTEMS WILL BE EVALUATED.

* information listed above is at the time of submission.

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