飛機(jī)減振降噪的新型適應(yīng)結(jié)構(gòu)阻抗控制途徑

1、 RTO-MP-AVT-110 16 - 1A Novel Adaptive Structural Impedance Control Approach toSuppress Aircraft Vibration and NoiseViresh Wickramasinghe, David Zimcik, and Yong ChenStructures, Materials and Propulsion Laboratory, Institute for Aerospace ResearchNational Research Council Canada, Ottawa, Ontario, Ca

2、nada K1A 0R6viresh.wickramasinghenrc-cnrc.gc.caABSTRACTSignificant levels of undesired vibration and noise are inherent in transport and combat vehicles, particularly in helicopters and propeller aircraft. Therefore, it is important to investigate techniques that reduce vibration and noise in the ca

3、bin to improve habitability, effectiveness, and safety for passengers. In addition, continuous exposure may lead to long-term physiological effects. In contrast to passive approaches, active techniques have the potential to suppress low frequency vibration and noise over a broadband of frequencies.

4、Various smart structure based techniques using active materials have been studied for vibration and noise suppression applications. These include active helicopters blades, variable twist propeller blades, adaptive damper, etc. Use of these techniques promises vast improvements in vibration and nois

5、e levels. However, full-scale implementations of these techniques have been hindered by electromechanical limitations of active materials. The Smart Spring is a novel approach to control combinations of impedance properties of a structure, such as stiffness, damping, and effective mass. It uses stac

6、ked piezoceramic actuators to adaptively vary structural impedance at strategic locations to suppress mechanical vibration. The Smart Spring is a versatile approach that can be implemented in a variety of applications. For example, an adaptive Smart Spring mount can be used to reduce vibration on ve

7、hicle seats, mitigate vibratory loads transmitted from engines, or suppress rotor vibration in helicopters. It is an unique concept that overcomes some of the difficulties encountered with other piezoceramic based vibration control approaches. Extensive experiments have demonstrated the ability of t

8、he Smart Spring to control structural impedance properties in an adaptive manner to suppress mechanical vibration. Wind tunnel tests have verified the ability of the Smart Spring to suppress both the vibratory displacement as well as the reaction force under unsteady excitation of a helicopter rotor

9、 blade.1.0 INTRODUCTIONUndesirable vibration is inherent in mechanical systems such as combat and transport vehicles but particularly high vibratory levels exist in helicopters and propeller aircraft. The main sources of vibration in these aircraft include harmonic vibrations induced by propeller or

10、 rotor, engine and gearbox operation, and structural excitations caused by unsteady aerodynamics. The vibration energy transferred throughout the aircraft structure not only leads to fatigue damage of expensive components and higher maintenance costs but also create a severe environment for passenge

11、rs and aircrew. In the short-term, the mechanical vibration transmitted to the human body increases fatigue, degrades comfort, interferes with effective performance, and influences operational safety 1. In addition, continuous exposure to repetitive vibrations transferred through the helicopter seat

12、s have known to cause damaging effects on the spine and neck of the aircrew leading to long-term occupational health issues 2.Paper presented at the RTO AVT Symposium on “Habitability of Combat and Transport Vehicles: Noise, Vibration andMotion”, held in Prague, Czech Republic, 4-7 October 2004, and

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16、es not display a currently valid OMB control number.1. REPORT DATE 01 OCT 2004 2. REPORT TYPEN/A3. DATES COVERED -4. TITLE AND SUBTITLEA Novel Adaptive Structural Impedance Control Approach to Suppress Aircraft Vibration and Noise 5a. CONTRACT NUMBER5b. GRANT NUMBER5c. PROGRAM ELEMENT NUMBER6. AUTHO

17、R(S5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER7. PERFORMING ORGANIZATION NAME(S AND ADDRESS(ESStructures, Materials and Propulsion Laboratory, Institute for Aerospace Research National Research Council Canada, Ottawa, Ontario, Canada K1A 0R6 8. PERFORMING ORGANIZATION REPORT NUMBER9. SPO

18、NSORING/MONITORING AGENCY NAME(S AND ADDRESS(ES10. SPONSOR/MONITORS ACRONYM(S 11. SPONSOR/MONITORS REPORT NUMBER(S12. DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release, distribution unlimited13. SUPPLEMENTARY NOTESSee also ADM201923, Habitability of Combat and Transport Vehicles: Noise,

19、 Vibration and Motion (Lhabitabilite des vehicules de combat et de transport: le bruit, les vibrations et le mouvement. , The original document contains color images.14. ABSTRACT15. SUBJECT TERMS16. SECURITY CLASSIFICATION OF:17. LIMITATION OF ABSTRACT UU 18. NUMBEROF PAGES1419a. NAME OFRESPONSIBLE

20、PERSONa. REPORT unclassifiedb. ABSTRACTunclassifiedc. THIS PAGEunclassifiedStandard Form 298 (Rev. 8-98 Prescribed by ANSI Std Z39-18A Novel Adaptive Structural Impedance Control Approach to Suppress Aircraft Vibration and Noise 16 - 2 RTO-MP-AVT-110Mechanical vibration also leads to structure-borne

21、 noise, which is a major contributor to the overall noise level in vehicles. In contrast to the airborne-noise which radiates directly from the source, structure-borne noise is generated as the fuselage and surrounding panels are excited by vibration transmitted from engines, rotors, etc. The short-

22、term effects of excessive human exposure to acoustic energy include, annoyance, degradation of voice communication and nausea 3. More importantly, the long-term exposure to high noise leads to hearing loss and modification of physiological functions within major organs 2. These irreversible effects

23、on human body due to noise and vibration are shown to manifest themselves by repeated exposure and passage of time. Therefore, reduction in vibration and noise in aircraft is important not only to improve habitability of the vehicle but also to mitigate long-term physiological effects on aircrew and

24、 passengers.Passive techniques such as insulators, stiffeners, dampers, and isolators are currently being used in aircraft to provide moderate reduction in noise and vibration. These passive techniques are successful only in reducing vibration and noise transmission in mid and high frequency ranges

25、2. However, the primary disturbance frequencies in propeller aircraft and helicopters are related to the blade passage frequency of the rotor, which is generally in the order of 100Hz. At such low frequencies, it is difficult to reduce the passage of noise into the cabin interior through the use of

26、passive approaches such as acoustic insulation due to the long wavelength associated with low frequency noise 4. In addition, passive approaches incur significant weight penalties and they are generally effective only in a narrow frequency band. In contrast, active approaches can be used in an effec

27、tive manner to suppress low frequency vibration and structure-borne noise significantly over a broadband of frequencies 5. More importantly, the adaptability of active systems enable optimization of the system performance due to changes in flight condition, vehicle configuration, weight of the cargo

28、, weight of the crew, etc. In the last decade, technologies based on smart structures approaches using active material actuators and sensors have become an enabler that cuts across traditional boundaries in material science and mechanical engineering. Active materials can be directly embedded into t

29、he vehicle structural design or smart systems can be added to structures to perform many functions, such as actuation, sensing or control. Active vibration and noise control is one of the areas that can exploit this emerging smart structures technology to its full extent in order to improve habitabi

30、lity in crew and passenger quarters of aircraft. The actuators in a smart system are driven by a real-time controller to mitigate the unwanted vibration or acoustic field measured by sensors. Several research programs based on smart structures concepts have been conducted to demonstrate potential im

31、provements in vibration as well as noise in aircraft.2.0 SMART STRUCTURES FOR NOISE AND VIBRATION APPLICATIONSVarious smart structures techniques using a variety of active materials have been studied for aircraft vibration and noise suppression applications. Some of the widely used active materials

32、include, piezoceramic (PZT, shape memory alloys (SMA, magnetorheological (MR and electrorheological (ER fluids 6. Each active material has unique characteristics and a few of the most advanced implementations are summarized below.2.1 Piezoelectric MaterialPiezoelectric (PZT material is one of the mo

33、st widely used active materials with inherent electrical and mechanical coupling characteristics. The stiffness of PZT is of the order of 70GPa. Therefore, a deformation caused by an electric field results in a significant mechanical force 7. The advantages of piezoceramic material are the high band

34、width and the ability to generate large forces necessary for structural actuation. However, the major barrier for application is the low stroke capability, which is less than 0.1% 8. This limited displacement often requires complex displacement amplifications or application of high voltages 9. UNCLA

35、SSIFIED/UNLIMITED UNCLASSIFIED/UNLIMITEDA Novel Adaptive Structural Impedance Control RTO-MP-AVT-110 16 - 3 UNCLASSIFIED/UNLIMITEDUNCLASSIFIED/UNLIMITEDA Novel Adaptive Structural Impedance Control 16 - 4 RTO-MP-AVT-110UNCLASSIFIED/UNLIMITEDUNCLASSIFIED/UNLIMITEDA Novel Adaptive Structural Impedance

36、 Control Approach to Suppress Aircraft Vibration and Noise RTO-MP-AVT-11016 - 52.2.1 Tab for In-Flight Rotor TrackingAn actuator based on SMAs is under development for continuous in-flight tracking of rotor blades. Proper blade tracking is important in helicopters because the vibration increases whe

37、n the path of each blade tip deviates from the rotating plane. At present, blades are trimmed manually by bending the tracking tab of the blade during major maintenance operations. Adjustments to the tab are performed on the ground and flight tests are conducted to verify the proper tracking. Once t

38、he blades are trimmed, the trim tab is not adjusted until the next major maintenance action. The SMA tracking tab improves vibration and noise in helicopters because it enables the rotor to be trimmed continuously. A SMA blade tab was tested to evaluate force, motion and temperature characteristics

39、and the results showed that the actuator met static and dynamic loading requirements for the in-flight blade tracking application 22. Full-scale flight hardware implementing this concept on a MD-900 rotor blade has successfully concluded whirl tower tests 23.2.2.2 Variable Twist Blade for Tiltrotor

40、AircraftA SMA actuator system is also under development to actively alter the twist distribution on a tiltrotor blade between hover and forward flight. The tiltrotor aircraft have the ability to combine the advantages of hovering flight of a helicopter with high speed forward flight of a fixed-wing

41、aircraft. However, the optimal blade twist and the planform distribution for these two regimes are different. Current tiltrotor blade design represent a compromise between optimum designs of the two fight conditions 24. Due to the non-optimized blade design, the tiltrotor aircraft not only have degr

42、aded performance but also have increased levels of vibration and noise. Recent advances in SMA actuator and advanced composite technologies are being used to optimize tiltrotor blade design for each flight condition in real-time. Preliminary tests show that variation of the blade twist by 6 degree b

43、etween hover and forward flight improves vibration and noise characteristics as well as aircraft performance 25.2.3 Magnetorheological and Electrorheological FluidMagnetorheological (MR and Electrorheological (ER fluids are typically composed of non-conducting oils and varying percentage of particle

44、s dispersed randomly throughout the oil substrate that exhibit reversible changes in rheological behaviour in the presence of a magnetic or electrical field, respectively. This change in the fluid viscosity from liquid state to gel-like state has enabled the development of several active damping dev

45、ices. The ER fluids include fine dielectric particles that align along the electric field to increase the yield stress of the fluid to 2-5kPa within 0.001 seconds 26. Similarly, MR fluids include iron particles that form a chain in the direction perpendicular to the fluid flow to increase the yield

46、stress to 50-100kPa under 0.01 seconds 26. Even through MR fluids have slower response time, MR fluids have been more widely used for active damper designs compared to their ER counterpart, since the amount of active fluid required for comparable mechanical damping performance in ER fluid is approxi

47、mately two orders of magnitude greater than that of a MR device 27. In addition, MR devices can be operated using common 12-28V power sources and MR fluid is not very sensitive to contaminants 27. These factors have increased practical application of MR fluid based devices compared to ER fluids.2.3.

48、1 Seat Vibration Suppression SystemA MR fluid based active damping system is currently integrated into vertical suspension seats widely used in vehicles to isolate passengers from whole body vibration and shock 28. This active system consists of a controllable MR fluid damper, a control computer int

49、egrated with a sensor and three-position ride mode switch offering light, medium or firm damping. These active dampers were tested for a range of frequencies, displacements, and input currents. The test results showed that the MR fluid damper was able to provide threeA Novel Adaptive Structural Impe

50、dance Control 16 - 6 RTO-MP-AVT-110A Novel Adaptive Structural Impedance Control RTO-MP-AVT-110 16 - 7A Novel Adaptive Structural Impedance Control 16 - 8 RTO-MP-AVT-110A Novel Adaptive Structural Impedance Control RTO-MP-AVT-110 16 - 9 UNCLASSIFIED/UNLIMITEDA Novel Adaptive Structural Impedance Con

51、trol 16 - 10 RTO-MP-AVT-110UNCLASSIFIED/UNLIMITEDA Novel Adaptive Structural Impedance Control Approach to Suppress Aircraft Vibration and Noise RTO-MP-AVT-110 16 - 116.0 REFERENCES1 Smith, D., “Characterizing the Effects of Airborne Vibration on Human Body Vibration Response,” Journal of Aviation,

52、Space, and Environmental Medicine, 73(3, 36-45, 2002.2 Castelo-Branco, N. A. A., and Rodriguez, E., “The Vibroacoustic Disease An Emerging Pathology,” Journal of Aviation, Space, and Environmental Medicine, 70(1, A1-A6, 1999.3 Mixon, J. S., and Wilby, J. F., “Interior Noise,” Acoustics of Flight Veh

53、icles, Theory and Practice, edited by H. H Hubbard, NASA Langley Research Center, Hampton, VA, 271-355, 1995.4 Gardonio, P., “Review of Active Techniques for Aerospace Vibro-Acoustic Control,” Journal of Aircraft, 39(2, 206-214, 2002.5 Giurgiutiu, V., “Recent Advances in Smart-Material Rotor Control

54、 Actuation,” 41st AIAA Structures, Structural Dynamics and Materials Conference, Atlanta, GA, 2000.6 Garg, D. P., and Anderson, G. L., “Structural Damping and Vibration Control via Smart Sensors and Actuators,” Journal of Vibration and Control, 9(12, 1421-1452, 2003.7 Jaffe, B., Cook, W. R., and Jaf

55、fe, H., Piezoelectric Ceramics, Academic Press, 1971.8 Chopra, I. “Review of State of Art of Smart Structures and Integrated Systems” American Institute for Aeronautics and Astronautics Journal, 40(11, 2145-2187, 2002.9 Brennan, M., J., Garcia-Bonito, J., et al., “Experimental Investigation of Diffe

56、rent Actuator Technologies for Active Vibration Control,” Journal of Smart Material Systems and Structures, 8(1, 145-153, 1999.10 Prechtl, E. F., and Hall, S. R., “Closed Loop Vibration Control Experiments on a Rotor with Blade Mounted Actuation,” 41st AIAA Structures, Structural Dynamics and Materi

57、als Conference, Atlanta, GA, 2000.11 Straub, F. K., Kennedy, D. K., et al., “Smart Material-actuated Rotor Technology - SMART,” Journal of Intelligent Material Systems and Structures, 15(4, 249-260, 2004.12 Straub, F. K., et al., “Development and Whirl-Tower Test of the Smart Material Actuated Rotat

58、or Technology (SMART Active Flap Rotor,” SPIE's 11th Conference on Smart Structures and Materials, San Diego, CA, 2004.13 Derham, R., Weems, D., Mathew, M. B., and Bussom, R., “The Design Evolution of an Active Materials Rotor,” 57th American Helicopter Society Annual Forum, Washington, DC, 2001.14 Wilbur, M. L., Mirick. P. H., et al. “Vibratory Loads Reduction Testing of the NASA/ARMY/MIT Active Twist Rotor,” Journal of the American Helicopter Society, 47, 123-133, 2002.15 Wickramasinghe, V. K., and Hagood, N. W., “Durability Characterization of Active Fiber Composit