helicopter ground resonance analysis

2, 1994, pp. It is mentioned here because octave analysis is often done in conjunction with tests also involving accelerometers, such as shock and vibration testing, and more. Ground resonance vibration never occurs at flight condition, but takes place when the helicopter is grounded and the rotor is revolving. This paper presents a stability robustness analysis of the helicopter ground-resonance phenomenon. Ground resonance is primarily a problem in a fully-articulated rotor system. Analysis of steady-state response regimes of a helicopter ground resonance model including a non-linear energy sink attachment . Download Full PDF Package. N.NAHAS Assistant Professor School of Mechanical Engineering King Abdul Aziz University, Saudi Arabia ABSTRACT Classic â¦ â¦ Abstract: An analytical model of helicopter rotor/airframe coupled system with fuselage state feedback is presented, and the effects of feedback coefficients on the helicopter ground resonance stability are investigated. or. A hingeless rotor helicopter, with in‐plane blade frequency less than rotor speed, is analyzed for its airborne and ground resonance characteristics. I talk about how ground resonance can lead to total destruction in a helicopter. environmental test methods for electronic and electrical equipment. Nonlinear analysis of helicopter ground resonance. The conditions are determined to be that the aircraft is operating at 5600 kg, main rotor speed 187 rpm, no Vibration Isolation System and no tire damping. helicopter ground resonance instability, and in protecting against such an i nstabil ity • Approximate method of DOnline!!.!. Joseph Morlier. jss 55555: 2012 (revision no. Anh Thai*, Stefan Stojanov*, Vijay Upadhya, James M. Rehg. To find out more, see our Privacy and Cookies policy. Simulation Analysis of Helicopter Ground Resonance Nonlinear Dynamics. The resemblance to the cable/pulley arrangement of Fig. The prediction of the stability boundary has been addressed for various helicopter configurations by using different methods. Dick, Erik, et al. However, the danger of Ground resonance may require dampers so touchdown shocks or jolts are not â¦ INTRODUCTION Ground resonance (GR) is an instability that can occur during landing or take-off conditions when a helicopter is in contact with the ground. The system degrees of freedom responsible for ground resonance are the fuselage rotational degrees of freedom and the blade lead-lag (in plane) degree of freedom. Édouard Belin, 31055 oulouse,T ancrFe Guilhem Michon 3 Université oulouse,T ICA, ISAE, 10 av. Google Scholar. This wheels more prone to ground resonance issue for the most part, has been eliminated with current wheel and strut designs. In helicopter with hinged blades, an unstable dynamic phenomenon known as ground resonance may occur during take-off and landing phase leading to the possible destruction of the aircraft. 91â101. Robustness Analysis of Helicopter Ground Resonance with Parametric Uncertainties in Blade Properties Leonardo Sanches 1 and Daniel Alazard 2 Université oulouse,T DMIA, ISAE, 10 av. Kaliskiego 2 00-908 Warsaw, Poland tel. The proposed method is applied to the ground resonance problem, cast in a form that isolates a closed loop containing the lead-lag damper, which is considered the uncertain component. Octave band analysis inside Dewesoft X data acquisition software Proceedings of the ASME 2015 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. NON-LINEAR GROUND RESONANCE OF A HELICOPTER DZYGADLO Zbigniew, KOWALECZKO Grzegorz Military University of Technology ul. Both static and dynamic analyses are done on various components of the helicopter model to define operational conditions in which ground â¦ Remember me on this computer. American Institute of Aeronautics and Astronautics 12700 Sunrise Valley Drive, Suite 200 Reston, VA 20191-5807 703.264.7500 The method of eigenvalue analysis is used to investigate the ground resonance stability of the helicopter rotor / body coupled system with two connections of dampers 採用特徵分析法計算了兩種減擺器連接形式的直升機地面共振穩定性。 Volume 8: 27th Conference on Mechanical Vibration and Noise. Detailed representation of the rotor-blade for a k-th blade. 4. UH-1 Helicopter Repairer (RC) (del 1310 / 1210 – 30) (MOS 15M) UH-1 Helicopter Repairer (RC) (del 1310 / 1210 – 30) (MOS 15M) is responsible for performing unit-level maintenance on assigned UH-1 aircraft. Remarkably, the 1940's gave birth to the study of ground resonance. It devotes two chapters to the aeroelastic response and stability analysis of isolated rotor blade in uncoupled and coupled modes. Classic theory of helicopter ground resonance studies the phenomenon on a planar model obtained by reducing the dynamic parameters of the full helicopter into the plane of rotation. The basic task of such system is to reconstruct an object with two cameras from different angles, a . Smart Materials and Structures is a multi-disciplinary journal dedicated to technical advances in (and applications of) smart materials, systems and structures; including intelligent systems, sensing and actuation, adaptive structures, and active control. Boston, Massachusetts, USA. Yan Zhu 1, Yu-hui Lu 1 and Ai-min Ling 1. Three chapters address the modeling of coupled rotor–fuselage dynamics and the associated flight dynamic stability, and provide a simplified analysis of the ground resonance aeromechanical stability of a helicopter. âA Basic Analysis of Helicopter Ground Resonance.â European Journal of Mechanical Engineering, vol. By using the lifting procedure the uncertain linear-time-periodic model â¦ Passive suppression of helicopter ground resonance using nonlinear energy sinks attached on the helicopter blades. If the indicated information is available, the Jesus nut is a slang term for the main rotor retaining nut or mast nut, which holds the main rotor to the mast of some helicopters.The related slang term Jesus pin refers to the lock pin used to secure the retaining nut. Ground resonance is a vibration that can be destructive to a helicopter. Ground resonance monitoring for hinged-blades helicopters: statistical CUSUM approach. Email. INTRODUCTION Ground resonance (GR) is an instability that can occur during landing or take-off conditions when a helicopter is in contact with the ground. Kunz, DL (2002) Nonlinear analysis of helicopter ground resonance. However, in order to develop control strategies for this phenomenon, the post-critical behavior … In this paper the phenomenon is studied on a spatial helicopter model of six degrees â¦ HELICOPTER GROUND RESONANCE Revision B By Tom Irvine Email: tomirvine@aol.com February 23, 2005 _____ Introduction A new helicopter design must undergo thorough testing to ensure â¦ There are several analysis methods to determine the helicopterâs stability in regard to ground resonance. Figura 1. By Floquet theory and transition matrix technology, the modal frequency and damping values are resoluted and verified by numerical simulations for … The effect is similar to the behavior of a washing machine when the clothes are concentrated in one place during the spin cycle. Édouard Belin, 31055 oulouse,T anrFec Alain Berlioz 4 91–101. When a helicopter, with a conventionally articulated rotor head, is resting on the ground with its rotor spinning, a condition called ground resonance can develop. Download PDF. 46, No. Power system analysis and design 5th. Utilizziamo cookie e altre … Modeling and Analysis of Helicopter Ground Resonance Utilizing Symbolic Processing and Dynamic Simulation Software; Manual of Flying: Volume 12: Helicopter; Helicopter Flying Handbook (FAA-H-8083-21B) Glossary & Index; Analytical and a Numerical Ground Resonance Analysis of a Conventionally Articulated Main Rotor Helicopter ... Tamer, A, Masarati, P (2015) Helicopter ground resonance investigation with dissimilar nonlinear lead â¦ 135, No. Robustness Analysis of Helicopter Ground Resonance with Parametric Uncertainties in Blade Properties Sanches, Leonardo; Alazard, Daniel; Michon, Guilhem; Berlioz, Alain; Abstract. Until the 1940's, it was admitted that the phenomenon is due to rotor-blade utter. jss 55555 : 2012. revision no. Ground resonance is an aeromechanic instability usually occurring during helicopter landing, take-off and ground manoeuvres [3] [7]. In helicopter with hinged rotor, an unstable dynamic phenomenon known as ground resonance may occur, leading to the total destruction of the aircraft. Related Papers. â¦ Comparison between two H/C configurations has given also a first sample of how structural variability can influence the modal layout. Physics of Fluids, Vol. Share to Facebook. helicopter ground resonance instability, and in protecting against such an i nstabil ity â¢ Approximate method of DOnline!!.!. HELICOPTER GROUND RESONANCE ANALYSIS USING MULTIBODY DYNAMICS A. Rezaeian, German Aerospace Center, Institute of Aeroelasticity, Bunsenstraße 10, 37073 Göttingen, â¦ If rotor RPM is very low during a ground resonance incident, complete shutdown may be sufficient. Video of a Brazilian rescue AS350BA breaking apart after landing due to ground resonance. Published under licence by IOP Publishing Ltd IOP Conference Series: â¦ First, a modal damping ratio function in the instable area for the fuselage without damping was constructed. L. N. Grodko, Ground Resonance of Helicopter on Its Run. Analysis and Control of Aeromechanical Instabilities in Helicopters. IMECE2015. Hence, we chose 100 m as the length scale for our analysis, which is also comparable to the shallow footprint of the AEM system. In these systems, ground â¦ Nonlinear Analysis: Real World Applications, Vol. A simplified approach to helicopter ground resonance - Volume 78 Issue 761. or. resonance flight ground voltage Prior art date 1964-07-01 Legal status (The legal status is an assumption and is not a legal conclusion. Robustness Analysis of Helicopter Ground Resonance with Parametric Uncertainties in Blade Properties Leonardo Sanches 1 and Daniel Alazard 2 Université oulouse,T DMIA, ISAE, 10 av. It is usually caused by the coupling between a rotor â¦ Ground resonance is an imbalance in the rotation of a helicopter rotor when the blades become bunched up on one side of their rotational plane and cause an oscillation in phase with the â¦ Recent works have studied ground resonance in helicopters under the aging or damage effects. Recent works have studied ground resonance in helicopters under the aging or damage effects. Password. The passive device consists of a set of essential cubic nonlinear absorbers named Nonlinear Energy Sinks (NES) each of them positioned on a blade. Elastic deformation and out of phase lagging â¦ +48 22 â¦ Ground Resonance - Free download as Powerpoint Presentation (.ppt / .pptx), PDF File (.pdf), Text File (.txt) or view presentation slides online. The proposed method is applied to the ground resonance problem, cast in a form that isolates a closed loop containing the lead-lag damper, which is considered the uncertain â¦ Log in with Facebook Log in with Google. 2]. Indeed, blade lead-lag stiffness may vary randomly with time and differ from â¦ Periodical Home; Latest Issue; Archive; Authors; Affiliations; Home Browse by Title Periodicals Nonlinear Analysis: Real World Applications Vol. or reset password. This analysis method used for ground resonance simulation test can give out the results according with real helicopter engineering tests. Close this message to accept cookies or find out how to manage your cookie settings. Publication: Journal of Guidance Control Dynamics. PURPOSE: A ground and flying resonance interpretation method of a helicopter and a recording medium with a computer program using the method are provided to simulate a flight mode according to a flight mode animation execution option, thereby distinguishing a mode with eyes. The present invention relates to a method for analyzing a ground and flight resonance of a helicopter and a recording medium storing a computer program according to the method. Nonlinear Inplane Flexbeam Stiffness Provides Rotor System Stability Without Lag Dampers. helicopters to save weight and volume or to allow the version to flotation devices. Email. The entire helicopter will self destruct. The cable resides in a plane midway between the anterior and posterior four-bar mechanisms for elevation/depression, extending from a fixed … 2010. Adaptive Structures and Material Systems. In: 36th European rotorcraft forum, Paris, France, 7â9 September 2010. Skip to main content Accessibility help We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Accreditation However, in order to study the behavior of the system when … Ground resonance is a â¦ Analysis of Helicopter Ground Resonance With Fuselage State Feedback Authors / Details: HU Guo-cai, HOU Zhi-Qiang, Naval Aeronautical Engineering Institute Recently Viewed Items. Helicopter ground resonance â a spatial model analysis DrM. Mbn .71. Causes and consequences. Ground resonance is usually precipitated by a hard landing or an asymmetrical ground contact, and is more likely to occur when components of the landing gear or damping system are improperly maintained, such as the drag hinge dampers, oleo struts, or wheel tire pressure. Modeling and analysis of helicopter ground resonance utilizing symbolic processing and dynamic simulation software by Robinson, Christopher S. Publication date 1997-03-01 â¦ A method of the ground resonance phenomenon analysis is presented in this paper. It has been carried out for a one-main rotor helicopter on the basis of a complete set of nonlinear differential equations, known in flight mechanics. NON-LINEAR GROUND RESONANCE OF A HELICOPTER DZYGADLO Zbigniew, KOWALECZKO Grzegorz Military University of Technology ul. Ground resonance is a mechanical instability affectingâ¦ View 2 excerpts, cites background References SHOWING 1-9 OF 9 REFERENCES Stability analysis of time-periodic systems using â¦ or reset password. Kaliskiego 2 00-908 Warsaw, Poland tel. â¦ For this analysis, we tested radii between 10 and 250 m. While correlation between these parameters and the resistivity increased significantly from 10 to 100 m, at radii above 100 m, correlation increased only slightly. This site uses cookies. Wereley, NM, & Costes, N. "Semi-Active Damping of Ground Resonance in Helicopters Using Magnetorheological Dampers." Share to Tumblr. Indeed, blade lead-lag stiffness may vary randomly with time and differ from blade to blade. Helicopter Ground Resonance Phenomenon With Blade Stiffness Dissimilarities: Experimental and Theoretical Developments 28 June 2013 | Journal of Vibration and Acoustics, Vol. (A) grasping a trend according to variables affecting the ground and flight resonance of a helicopter, Driving a ground and flight resonance analysis program for calculating a result of flight … Google has not performed a legal analysis and â¦ A short summary of this paper. on. Analysis of Helicopter Ground Resonance With Fuselage State Feedback. A helicopter is a type of rotorcraft in which lift and thrust are supplied by horizontally spinning rotors.This allows the helicopter to take off and land vertically, to hover, and to fly forward, backward and laterally.These attributes allow helicopters to be used in congested or isolated areas where fixed-wing aircraft and many forms of STOL (Short TakeOff and Landing) or … Tamer, A, & Masarati, P. "Helicopter Ground Resonance Investigation With Dissimilar Nonlinear Lead-Lag Dampers." The latest Lifestyle | Daily Life news, tips, opinion and advice from The Sydney Morning Herald covering life and relationships, beauty, fashion, health & wellbeing , N b The aging or failure of mechanical elements comprising the â¦ analysis The analysis is based on a helicopter model with â¦ Non è possibile visualizzare una descrizione perché il sito non lo consente. Robustness Analysis of Helicopter Ground Resonance with Parametric Uncertainties in Blade Properties Sanches, Leonardo; Alazard, Daniel; Michon, Guilhem; Berlioz, Alain; Abstract. This emergency situation can result in the entire hull being ripped apart by the air â¦ By â¦ 3, No. In Proceedings of 6.9 is clearly apparent. The requirements of fuselage natural frequency and damping for meeting ground resonance stability were given by … 3) directorate of standardisation department of defence production ministry of defence ‘h’ block, nirman bhawan po new delhi - 110 011 jss 55555 : 2012 revision no. Ahmed Jhinaoui. The system â¦ In helicopter with hinged blades, an unstable dynamic phenomenon known as ground resonance may occur during take-off and landing phase leading to the possible destruction of the aircraft. Analysis of Helicopter Ground Resonance With Fuselage State Feedback Authors / Details: HU Guo-cai, HOU Zhi-Qiang, Naval Aeronautical Engineering Institute Recently Viewed Items. This is a destructive harmonic vibration caused by a dynamic reaction â¦ Figura 2. Helicopter ground resonance is a self exited dynamic instability, which may occur when helicopter is in contact with the ground. Abstract: An analytical model of helicopter rotor/airframe coupled system with fuselage state feedback is presented, and the effects of feedback coefficients on the helicopter ground â¦ Modeling and analysis of helicopter ground resonance utilizing symbolic processing and dynamic simulation software Item Preview remove-circle Share or Embed This Item. This graph represents two efforts to identify genetic variants associated with schizophrenia — and the ‘discovery gap’ where future variants might be … Nonlinear Analysis: Real World Applications. The influence of stiffness dissimilarities between blades on the stability of the ground resonance phenomenon was determined through numerical investigations into the … L. Sanches. Nonlinear Analysis: Real World Applications. By continuing to use this site you agree to our use of cookies. Presentation discusses the ground resonance in â¦ joint services specification. Many helicopters also have damping features within the rotor system as well, such as the 300CB. Should ground resonance be suspected and rotor RPM allows, the pilot should immediately lift the helicopter off the ground, stopping the resonance. When a helicopter is resting on the ground with its rotor spining, a condition called "ground resonance" can develop. Although the spring stiffness and cable routing have not been finalized, the preliminary routing of the cable and pulley placement are included in the model. Abstract Classic theory of helicopter ground resonance studies the phenomenon on a planar model obtained by reducing the dynamic parameters of the full helicopter into the plane of â¦ Mechanical model of a four-bladed helicopter rotor for GR analysis. Guo-cai, H, Jin-wu, X, â¦ Close this notification Zherebtsov, Dynamic Stability of â¦ Ground resonance is an imbalance in the rotation of a helicopter rotor when the blades become bunched up on one side of their rotational plane and cause an oscillation in phase with the frequency of the rocking of the helicopter on its landing gear. We … Rankings. DTIC AD0785628: Helicopter Ground Resonance Analysis in Light of Army Requirements Item Preview remove-circle Share or Embed This Item. Abstract: To meet the requirement of helicopter ground resonance stability, an optimal design method for landing gear stiffness and damping is proposed. It is usually caused by the coupling between a rotor system vibration with an oscillation of the fuselage rocking on its landing gear. Proceedings of the ASME 2000 International Mechanical Engineering Congress and Exposition. Compra Modeling and Analysis of Helicopter Ground Resonance Utilizing Symbolic Processing and Dynamic Simulation Software. CONSTITUTION: A file selected by a user or a ground and flying resonance interpretation signal … Amrita University is the only Indian University in World’s Top 100 Universities in Times Higher Education Impact Rankings. The problem is solved for linear and nonlinear models of the damper, illustrating how stability requirements can be used to determine uncertainty bounds on the stiffness and … Remember me on this computer. â¦ This paper investigates the passive control of a rotor instability named helicopter Ground Resonance (GR). Journal of the American Helicopter Society, Vol. 2 Ground resonance theory Ground resonance is an aeromechanic instability usually occurring during helicopter landing, take-off and ground manoeuvres [3] [7]. Dewesoft octave analysis solution meets all of the IEC and ANSI Class I specifications for octave filters. × Close Log In. Comparison and validation of various turbulence models for U-bend flow with a magnetic resonance velocimetry experiment. â¦ Dick, Erik, et al. Helicopter ground resonance analysis using multibody dynamics. Ya. Need an … Four steady-state responses are highlighted and explained analytically: complete suppression, partial suppression through strongly modulated response, partial suppression â¦ Schizophrenia’s discovery gap. control problems, as for an instance, the aeroelastic ut-ter (Bueno et al., 2015).