Ground and Flight Test Structural Excitation Using Piezoelectric Actuators

Ground and Flight Test Structural Excitation Using Piezoelectric Actuators
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Total Pages: 20
Release: 2002
Genre: Actuators
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A flight flutter experiment at the National Aeronautics and Space Administration (NASA) Dryden Fight Research Center, Edwards, California, used an 18-inch half-span composite model called the Aerostructures Test Wing (ATW). The ATW was mounted on a centerline flight test fixture on the NASA F-15B and used distributed piezoelectric strain actuators for in-flight structural excitation. The main focus of this paper is to investigate the performance of the piezoelectric actuators and test their ability to excite the first-bending and first-torsion modes of the ATW on the ground and in-flight. On the ground, wing response resulting from piezoelectric and impact excitation was recorded and compared. The comparison shows less than a 1-percent difference in modal frequency and a 3-percent increase in damping.

Prediction and Control of Twin-Tail Buffet of Fighter Aircraft

Prediction and Control of Twin-Tail Buffet of Fighter Aircraft
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Total Pages: 0
Release: 2002
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High-fidelity multidisciplinary analysis capabilities for the prediction and control of tail buffeting of fighter aircraft have been developed and extensively validated for the F/A-18 aircraft. The computational results compared very well with flight and several experimental data. The results indicated that the vertical tail is subject to both bending and torsional responses, mainly in the first mode. The buffet excitation peaks shift to lower frequency as the angle of attack increases. Capabilities for buffet alleviation have been demonstrated using LEX fences and vortical blowing. A parametric study for both the active and passive flow control has been conducted. Capabilities for actively controlling the vertical tail structure have been demonstrated by strengthening the F/A-18 vertical tail using piezoelectric actuators.

Progress and New Techniques in Buffet Alleviation

Progress and New Techniques in Buffet Alleviation
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Total Pages: 0
Release: 1997
Genre:
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Research for twin-tail buffet alleviation is centered on ground tests, wind tunnel tests, and computational fluid dynamics (CFD) analysis. The objective of the research is to improve present technology to obtain a significant reduction in vibration due to buffet. One of the techniques for active control of buffet is the use of smart structures with piezoelectric actuators. The actuators are embedded in the vertical tails in the most advantageous locations to reduce the response of the various structural modes of vibration due to buffet excitation. Ground and wind tunnel tests are necessary to ascertain the piezoelectric actuator's authority at full loads. It is also necessary to evaluate the increase in weight compared with the increase in damping. The results using two different types of piezoelectric actuators are encouraging. In-house wind tunnel tests on a 4.7% scale model of an F-15C aircraft were also conducted to ascertain the effects of tangential blowing and piezoelectric actuators. The tests were performed in the SARL (Subsonic Aerodynamics Research Laboratory) wind tunnel. Tangential blowing had some effect at lower angles of attack. A numerical investigation was conducted simultaneously. This report presents an overview of the buffet research at various organizations, results of the in-house wind tunnel test, and a summary of the computational effort.