Academic literature on the topic 'Orbit motion limited'
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Journal articles on the topic "Orbit motion limited"
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Yao, Peter, and Timothy Sands. "Micro Satellite Orbital Boost by Electrodynamic Tethers." Micromachines 12, no. 8 (July 31, 2021): 916. http://dx.doi.org/10.3390/mi12080916.
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In this manuscript, a method for maneuvering a spacecraft using electrically charged tethers is explored. The spacecraft’s velocity vector can be modified by interacting with Earth’s magnetic field. Through this method, a spacecraft can maintain an orbit indefinitely by reboosting without the constraint of limited propellant. The spacecraft-tether system dynamics in low Earth orbit are simulated to evaluate the effects of Lorentz force and torques on translational motion. With 500-meter tethers charged with a 1-amp current, a 100-kg spacecraft can gain 250 m of altitude in one orbit. By evaluating the combined effects of Lorenz force and the coupled effects of Lorentz torque propagation through Euler’s moment equation and Newton’s translational motion equations, the simulated spacecraft-tether system can orbit indefinitely at altitudes as low as 275 km. Through a rare evaluation of the nonlinear coupling of the six differential equations of motion, the one finding is that an electrodynamic tether can be used to maintain a spacecraft’s orbit height indefinitely for very low Earth orbits. However, the reboost maneuver is inefficient for high inclination orbits and has high electrical power requirement. To overcome greater aerodynamic drag at lower altitudes, longer tethers with higher power draw are required.
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Muzzio, J. C., F. C. Wachlin, and D. D. Carpintero. "Regular and Chaotic Motion in a Restricted Three–Body Problem of Astrophysical Interest." International Astronomical Union Colloquium 174 (2000): 281–85. http://dx.doi.org/10.1017/s0252921100055123.
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AbstractWe have studied the motion of massless particles (stars) bound to a stellar system (a galactic satellite) that moves on a circular orbit in an external field (a galaxy). A large percentage of the stellar orbits turned out to be chaotic, contrary to what happens in the usual restricted three–body problem of celestial mechanics where most of the orbits are regular. The discrepancy is probably due to three facts: 1) Our study is not limited to orbits on the main planes of symmetry, but considers three–dimensional motion; 2) The force exerted by the satellite goes to zero (rather than to infinity) at the center of the satellite; 3) The potential of the satellite is triaxial, rather than spherical.
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DVORAK, RUDOLF. "THE ROLE OF RESONANCES IN PLANETARY SYSTEMS." International Journal of Bifurcation and Chaos 16, no. 06 (June 2006): 1633–44. http://dx.doi.org/10.1142/s021812740601557x.
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This paper reviews the important role of resonances in the structure of planetary systems. After a short introduction to the basics of orbital dynamics of motion in resonances we describe the dynamics of our planetary systems and also of extrasolar planetary systems, where up to now more than 100 are known. In our planetary system the planets move in quite regular orbits with small eccentricities although it was found that the motion of the inner planets is "slightly" chaotic on time scales of tenths of millions of years. The quasi regularity (close to so-called quasi-periodic motion on a torus) is not true for the small bodies: the main belt of asteroids between Mars and Jupiter with gaps for special values of semimajor axes on one hand and with families of many small bodies on the other, is sculpted due to the presence of first mean motion resonances with Jupiter and second secular resonances with long-periodic motions of the nodes and perihelia of Jupiter and Saturn. In extrasolar systems the planets — rather surprisingly — are found to move sometimes in very high eccentric orbits when they are at distances comparable to the size of our planets. Because of our still limited observational techniques using indirect methods we have only discovered massive planets comparable to the size of Jupiter. When these planets orbit alone around their host star our research aims at the possibility of additional terrestrial planets moving in such a system. Because of mostly large eccentricities here the resonances are, in contrary to our planets, essential for the stability of orbits, and may protect or destroy an orbit. On the other hand, in multiple planetary systems we concentrate on the stability of their orbits as they are observed: a very interesting new result is that most of these multiple planetary systems with high eccentric orbits move in resonances with a special configuration which protects them from close encounters although these orbits are crossing.
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Wan, Neng, Ming Liu, and Hamid Reza Karimi. "Observer-Based Robust Control for Spacecraft Rendezvous with Thrust Saturation." Abstract and Applied Analysis 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/710850.
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This paper proposes an observer-based robust guaranteed cost control method for thrust-limited rendezvous in near-circular orbits. Treating the noncircularity of the target orbit as a parametric uncertainty, a linearized motion model derived from the two-body problem is adopted as the controlled plant. Based on this model, a robust guaranteed cost observer-controller is synthesized with a less conservative saturation control law, and sufficient condition for the existence of this observer-based rendezvous controller is derived. Finally, an illustrative example with immeasurable velocity states is presented to demonstrate the advantages and effectiveness of the control scheme.
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Zhao, Guo Wei, Bin Tang, Liang Sun, and Xing Min Zhang. "Effect and Control of Pendular Motion of Abandoned Satellite on Tether Drag System." Applied Mechanics and Materials 513-517 (February 2014): 3900–3906. http://dx.doi.org/10.4028/www.scientific.net/amm.513-517.3900.
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As a kind of typical on-orbit capture and aberrance technology, space tether de-orbit system has broad application prospect in terms of cleaning space debris and abandoned satellites. In the paper, the attitude dynamics equations of the tether de-orbit system is established based on law of moment of momentum; Against the background of de-orbiting under a constant thrust in the tangential direction, the optimized PD control law with limited attitude feedback on jet control and momentum wheel control is designed for the mission satellite; The oscillation characteristics of the attitude of abandoned satellite are studied, and the effect of the oscillation on the tethered system and based satellite are analyzed; According to the demand for maintaining the position and suppressing the oscillation of the abandoned satellite, a kind of tension control method is put forward. Numerical simulation results indicate that the abandoned satellite oscillates at a specific angular frequency, and the large amplitude threatens the stabilization of tethered system; the designed tension control method effectively eliminate the oscillation of the abandoned satellite and ensure the flight safety of the tether de-orbit system, with economic energy consumption for the control of the based satellite.
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Pilch, I., D. Söderström, M. I. Hasan, U. Helmersson, and N. Brenning. "Fast growth of nanoparticles in a hollow cathode plasma through orbit motion limited ion collection." Applied Physics Letters 103, no. 19 (November 4, 2013): 193108. http://dx.doi.org/10.1063/1.4828883.
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Yang, Ruihong, Zhongguo Song, Jinsheng Zhang, and Xiaoli Xi. "A fast cold-start method of GPS receiver based on satellite orbit prediction." MATEC Web of Conferences 198 (2018): 06005. http://dx.doi.org/10.1051/matecconf/201819806005.
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Time to first fix (TTFF) is one of the crucial indicators to evaluate the performance of a GPS receiver. In this paper, an orbit prediction algorithm to reduce the TTFF of GPS receivers without a network connection is presented. Satellite orbit is predicted by numerically integrating the satellite’s equation of motion. Satellite’s initial position and velocity value, as well as the Earth’s polar motion parameters, used in prediction correspond to the locally collected previous broadcast ephemeris. As the solar radiation pressure (SRP) is one of the most critical factors causing orbit prediction error, an empirical SRP model with two parameters that change with the movement of satellite and Earth is also described. The presented algorithm is verified by GPS satellites using the initial conditions divided from three groups of broadcast ephemeris data. Simulation results show that, with the SRP model described in this paper the satellite’s position error limited to 30 meters within 7 days prediction.
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Sukhanov, A. A., and A. F. B. A. Prado. "Low-Thrust Orbital Transfers in the Two-Body Problem." Mathematical Problems in Engineering 2012 (2012): 1–20. http://dx.doi.org/10.1155/2012/905209.
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Low-thrust transfers between given orbits within the two-body problem are considered; the thrust is assumed power limited. A simple method for obtaining the transfer trajectories based on the linearization of the motion near reference orbits is suggested. Required calculation accuracy can be reached by means of use of a proper number of the reference orbits. The method may be used in the case of a large number of the orbits around the attracting center; no averaging is necessary in this case. The suggested method also is applicable to the cases of partly given final orbit and if there are constraints on the thrust direction. The method gives an optimal solution to the linearized problem which is not optimal for the original nonlinear problem; the difference between the optimal solutions to the original and linearized problems is estimated using a numerical example. Also examples illustrating the method capacities are given.
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Wan, Neng, Ming Liu, and Hamid Reza Karimi. "Robust Tracking Control for Rendezvous in Near-Circular Orbits." Mathematical Problems in Engineering 2013 (2013): 1–11. http://dx.doi.org/10.1155/2013/726945.
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This paper investigates a robust guaranteed cost tracking control problem for thrust-limited spacecraft rendezvous in near-circular orbits. Relative motion model is established based on the two-body problem with noncircularity of the target orbit described as a parameter uncertainty. A guaranteed cost tracking controller with input saturation is designed via a linear matrix inequality (LMI) method, and sufficient conditions for the existence of the robust tracking controller are derived, which is more concise and less conservative compared with the previous works. Numerical examples are provided for both time-invariant and time-variant reference signals to illustrate the effectiveness of the proposed control scheme when applied to the terminal rendezvous and other astronautic missions with scheduled states signal.
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BERBRI, ABDERREZAK, and MOULOUD TRIBECHE. "A note on the trapped electron dust grain current." Journal of Plasma Physics 75, no. 5 (October 2009): 587–91. http://dx.doi.org/10.1017/s0022377809990110.
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AbstractIt is shown that when the non-isothermal trapped electron current is rederived based on the orbit-limited motion theory, the variable dust charge can be expressed in terms of the Lambert function. One can then take advantage of this new transcendental function to illustrate how variable-charge nonlinear trapped dust modes can be investigated semi-analytically.
Dissertations / Theses on the topic "Orbit motion limited"
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Daryanani, Roshan D. "Potential distribution around dust particles in plasmas." Thesis, University of Oxford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337811.
Full textBook chapters on the topic "Orbit motion limited"
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Jordan, David, Louise Mawn, and Richard L. Anderson. "The Extraocular Muscles." In Surgical Anatomy of the Ocular Adnexa. Oxford University Press, 2012. http://dx.doi.org/10.1093/oso/9780199744268.003.0011.
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Whereas skeletal muscles generally perform specific limited roles, extraocular muscles (EOMs) have to be responsive over a wider dynamic range. As a result, EOMs have fundamentally distinct structural, functional, biochemical, and immunological properties as compared to other skeletal muscles. At birth, the extraocular muscles are at approximately 50 % to 60 % of their final dimension. Their relative growth within the enlarging orbit and their angular relations with the globe remain nearly constant from infancy to adulthood. The adult rectus muscles are approximately the same length (40 mm) but differ in thickness and in the length of their tendons. There are six extrinsic, or extraocular, muscles of the eye: four recti and two obliques. Only the horizontal and vertical recti insert on the eyeball in front of its equator. Both obliques have their insertions behind the equator of the globe. All six muscles consist of striated muscle fibers with abundant elastic fibers. The EOMs have muscle fibers and innervations that differ from those of skeletal muscle. There are three distinct types of muscle fibers (fine, granular, and coarse) that contribute to the action of the EOMs. The fine fibers are thought to be responsible for slow twitch movements, the granular fibers for fast twitch movements, and the coarse fibers for slow tonic movements. The EOMs are more richly innervated than other voluntary muscles of the body and have three types of nerve terminals: single endplate (driving eye movements), multiple endplates (tonic tension), and palisade endings (can be sensory receptors). In addition, there are both singly and multiply innervated nerve fibers present. EOMs are able to vary their contractile force by small increments. The maximum firing frequency of ocular motor units is about four times greater than those of limb muscle motor units. To allow them to operate at a higher frequency, EOMs also have faster contractile properties, with their time to peak tension and their one-half relaxation time being at least half of those in limb muscles.
Conference papers on the topic "Orbit motion limited"
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Wu, Fenglei, Jingyong Liu, Yongqing Liu, Yanning Li, Ping Zhu, and Liming Du. "A method for the orbit determination accuracy improvement of a station with a limited motion antenna." In International Conference on Space Information Technology 2009, edited by Xingrui Ma, Baohua Yang, and Ming Li. SPIE, 2009. http://dx.doi.org/10.1117/12.855620.
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Brewer, W. V. "Full-Wave Bi-Directional Rotation-Rectifier to Assist Robotic End-Effectors in the Automated Assembly of Large Truss Structures in Space." In ASME 1992 Design Technical Conferences. American Society of Mechanical Engineers, 1992. http://dx.doi.org/10.1115/detc1992-0253.
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Abstract In 1987 work was initiated on the Automated Structural Assembly Laboratory (ASAL) at NASA/LaRC to demonstrate the feasibility of robotic construction in orbit. To move itself as the structure grows, the robot is mounted on a carriage that traverses a beam which moves longitudinally, similar to a gantry crane. Gantry motions will be operated by the self-sufficient robot with its wrist roll motion. Interfaces for the robot at each gantry motor shaft are provided for that purpose. Wrist roll is limited by the large and growing number of wires that must communicate thru the wrist joint to connect the end-effector to power, sensory devices, and computation services. Rotation-Rectifiers applied to robot mobility simplify the end-effector to motor shaft interface, reduce the number of interface operations that must be performed, and convert oscillating robot wrist roll motions to continuous rotation in either direction.
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Stutz, Colin, Douglas Bohl, and Melissa Green. "Wake Properties of an Oscillating Airfoil Undergoing Small Amplitude Asymmetric Oscillation." In ASME 2020 Fluids Engineering Division Summer Meeting collocated with the ASME 2020 Heat Transfer Summer Conference and the ASME 2020 18th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/fedsm2020-20360.
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Abstract The flow around, and in the wake of, pitching airfoils has received renewed interest due to its potential for thrust production at low Reynolds numbers. Past work has centered on the flow fields generated by symmetric pitching of the airfoil. Studies investigating the effects of asymmetric motion are more limited. This work focuses on the wake patterns developed due to asymmetric pitching. Particle Image Velocimetry (PIV) is used to quantify the flow field around a NACA0012 airfoil undergoing small amplitude, high frequency asymmetric pitching. The airfoil is pitched about the quarter chord point with an amplitude of ±4° at reduced frequencies of k = 2.6–5.8 at a Rec = 12000. Pitching symmetries of 50/50, 40/60 and 30/70 are studied, where the symmetry is defined by the fraction of the cycle spent in the pitch down versus pitch up motion. The data show that for the 50/50 (symmetric) motions two alternating sign vortices, with equivalent strength, are formed as expected. The asymmetric cases show that a single vortex is formed during the “fast” portion of the pitching motion. Multiple vortices are formed during the “slow” portion of the pitching motion. The number of secondary vortices and the downstream evolution of the vortices depends on the symmetry value. In some cases they remain isolated but orbit other vortical structures, while in other cases they pair with other vortical structures, and finally when the reduced frequency and asymmetry values are high enough the vortex array shows interaction between cycles.
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Beregi, Sándor, Dénes Takács, and David A. W. Barton. "Hysteresis Effect in the Nonlinear Stability of Towed Wheels." In ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/detc2017-67722.
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In this paper the dynamics of towed elastic wheels are studied with the help of the brush tyre model. To calculate the lateral deformation of the contact patch centre-line distributed time-delay is taken into account for the rolling parts, whereas parabolic limits are used to determine the deformation in case of side-slip. After linear stability analysis of the rectilinear motion the limit cycles of the non-smooth time-delayed system are calculated with the method of numerical collocation. With the help of bifurcation diagrams it is demonstrated how the periodic orbits develop from the linear stability boundary in a structure characteristic of piecewise-smooth systems. Moreover, it is shown that the contact memory effect and the dry friction yield bistable parameter ranges besides the linearly unstable domains. Namely, for one particular towing velocity a stable equilibrium corresponding to straight-line motion and a stable periodic orbit coexist resulting a hysteresis effect in the stability of the straight-line motion.
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Torres, Jorge E., and Sergio E. Di´az. "Finite Length Squeeze Film Dampers With Air Entrainment: Non-Dimensional Maps and Their Applicability." In ASME Turbo Expo 2010: Power for Land, Sea, and Air. ASMEDC, 2010. http://dx.doi.org/10.1115/gt2010-22561.
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Squeeze Film Dampers (SFDs) are bearings that support large motion amplitudes when traversing rotor-bearing systems critical speeds. Actual practice demands bearings with operating conditions of low oil supply pressure and high frequency. In open-ended SFDs, large amplitudes of journal motion draw air into the film gap. The air ingested and entrapped results in a bubbly mixture that affects the dynamic performance and the overall damping capability of the SFDs. Diaz and San Andre´s [11] developed a model to predict the amount of air ingested into SFDs with open-ends. They proposed an innovative non-dimensional number to estimate the amount of air entrapped in the film gap, but their analytical results are limited to short length bearings. Mendez et al. [13] extended the results of Diaz and San Andre´s to finite length bearings, devising a Finite Volume Method (FVM) scheme. Even though their research presented new and significant results, they lack wider applicability that includes different geometries or boundary conditions. The present research proposes the solution of the Reynolds equation by the finite element method. Results computed by this formulation explore non-dimensional maps for determination of the amount of entrapped air. The results show that for fixed lubricant properties the amount of entrapped air depends exclusively on three dimensionless parameters: feed-squeeze flow number, length to diameter ratio, and dimensionless orbit radius.
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Inayat-Hussain, Jawaid Iqbal, Hiroshi Kanki, and Njuki W. Mureithi. "Bifurcations and Chaos in the Response of a Rigid Rotor Supported by Eccentric Squeeze-Film Dampers." In ASME 2001 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/detc2001/vib-21573.
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Abstract In the unbalance response analysis of rotors supported by squeeze-film dampers with centering springs, the fluid-film forces are usually computed based on the assumption that the rotor exhibits a circular centered whirl orbit motion. The validity of this assumption is, however, limited to the ideal case of squeeze-film dampers with centering springs that are perfectly adjusted to offset the gravitational force. In most practical applications, eccentric operation of these dampers is almost unavoidable since precise setting of the centering springs in a real environment is usually not possible. In this paper the bifurcations in the response of a rigid rotor in eccentric squeeze-film dampers are investigated. The values of the bearing parameter (B), gravity parameter (W) and spring parameter (S) are respectively fixed at 0.015, 0.05 and 0.3, while the unbalance parameter (U) is varied from 0.05 to 0.8. The results indicated that the rotor might lose its stability due to period-doubling and saddle node bifurcations. Chaotic response of the rotor was also observed for 0.365 < U < 0.367 and 0.381 < U < 0.392. The transitions to chaos in these two regimes were respectively via the period-doubling and type 3 intermittency routes. The levels of rotor unbalance where non-synchronous and chaotic motions were observed in this study are only an order of magnitude higher than the specified levels for rigid rotors. Such levels of unbalance may easily occur in practice due to in-service erosion or in the event of a partial or an entire blade loss.
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Artiles, Antonio F. "The Effects of Friction in Axial Splines on Rotor System Stability." In ASME 1991 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1991. http://dx.doi.org/10.1115/91-gt-251.
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An in depth parametric evaluation of the effects of Coulomb friction in an axial spline joint on the stability of the rotor-bearing system was conducted through time transient integration of the equations of motion. Effects of: spin speed, friction coefficient, spline torque, external damping, imbalance and side load as well as asymmetric bearing stiffnesses were investigated. A subsynchronous instability is present at the bending critical speed when the spin speed is above this critical. The limit cycle orbit is circular, is proportional to the product of the friction coefficient and spline torque (μT), is inversely proportional to the external damping and is independent of spin speed. When imbalance is applied to the rotor, beating between the subsynchronous natural frequency and the synchronous (spin speed) frequency occurs. The subsynchronous component of the orbit is proportional to μT, while the synchronous component is proportional to the imbalance. When a static side load is applied, the unstable node at the center of the orbitally-stable limit cycle grows into an elliptical orbitally-unstable limit cycle, separating stable - from unstable regions of the phase plane. Below a threshold value of side load, the transient motion approaches one of two asymptotic solutions depending on the initial conditions: the larger stable limit cycle or a point at the center of the smaller unstable limit cycle. Beyond the threshold value of side load the rotor-bearing system is stable and all motions decay to a point. Asymmetry in the bearing stiffnesses reduces the size of the subsynchronous whirl orbit.
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Quinn, D. Dane. "Slow Escapes From Resonance." In ASME 1995 Design Engineering Technical Conferences collocated with the ASME 1995 15th International Computers in Engineering Conference and the ASME 1995 9th Annual Engineering Database Symposium. American Society of Mechanical Engineers, 1995. http://dx.doi.org/10.1115/detc1995-0314.
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Abstract We study a Hamiltonian system of coupled oscillators that approximate two forced pendulums, connected with a torsional spring. The uncoupled limit is described by two identical oscillators, each possessing a homoclinic trajectory separating bounded from unbounded motion. Unlike previous work by Rand and Quinn on a dissipative system of coupled homoclinic oscillators [11], the coupling preserves the Hamiltonian structure of this system. However, integrability is destroyed and we resort to analytic and numerical techniques to describe the motion of the system. We focus on intermediate energy levels which lead to detained motions, defined as trajectories that, though unbounded, oscillate within the region defined by the homoclinic orbit of the unperturbed system for a long but finite time. These detained motions coexist with truly bounded trajectories that are contained within isolating first integrals. We analyze the existence and behavior of these motions in terms of equipotential surfaces. These curves represent bounds on the motion of the system and are shown to be closed for low energies. However, above some critical energy level the equipotential curves become open. The detained trajectories are shown to be a result of these open curves and the stochasticity of near-integrable Hamiltonian systems.
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Franklin, Wes, and Donald E. Bently. "Complex Variable Filtering: The Next Step in Rotor Diagnostics." In ASME Turbo Expo 2001: Power for Land, Sea, and Air. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/2001-gt-0242.
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Currently most rotor diagnostic algorithms focus on extracting as much information as possible from the signal of a single transducer. This limits these algorithms to only processing information about the projection of the rotor motion onto the probe axis. Utilizing single probes is adequate for isotropic systems where the projections are the same for any probe orientation. However, for anisotropic systems the results of the algorithm can be different depending on the orientation of the measurement transducer. This leads to the blind men and elephant conflict, multiple descriptions of the same animal, or in our case rotor motion. For example, if the transducer is located on the minor axis a great running machine, on the major axis a machine that needs balancing. The phase is also inconsistent, rotate the transducer a few degrees and the indicated phase jumps drastically. If the transducer is on the ellipse axis the high spot and heavy spot are together below the resonance, move the probe off the axis and the high spot and heavy spot are no longer related. More sophisticated diagnostic methodologies which correlate data from multiple axial locations, such as relative phase and modeshape, are affected even more than balancing by the phase inconsistency. What is really desired, is information about the actual motion of the shaft in the two dimensional plane. Up until recently the only data presentation format that addressed the planer motion was orbit. Orbits are powerful diagnostic tools, but have the limitation of only showing motion at one speed. What is needed are similar processing techniques that present complete motion over the entire speed range and report the same information for all probe orientations, such as complex variable filtering. This paper presents the concept of complex variable filtering and explores some situations in which it provides superior results to those obtained utilizing conventional single probe techniques.
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Schiffmann, J., and Z. S. Spakovszky. "Foil Bearing Design Guidelines for Improved Stability." In ASME 2012 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/detc2012-70899.
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Experimental evidence in the literature suggests that foil bearing supported rotors can suffer from sub-synchronous vibration. While dry-friction between top foil and bump foil is thought to provide structural damping, sub-synchronous vibration is still an unresolved issue and has been recently attributed to the non-linearity of the bump-foil support stiffness. A non-linear rotordynamic model corroborates this hypothesis, however a forcing is required to excite the system. The current paper aims to shed new light onto this matter and discusses the impact of various design variables on stable foil bearing supported rotor operation. It is shown that, while a time domain integration of the equations of motion of the rotor coupled with the Reynolds equation for the fluid film is necessary to quantify the evolution of the rotor orbit, the underlying mechanism and the onset speed of instability can be predicted by coupling a reduced order foil bearing model with a rigid-body, linear rotordynamic model. Using this model it is shown that the excitation source inducing sub-synchronous vibration is a classical aerodynamic instability resulting from bearing fluid film forces. A sensitivity analysis suggests that structural damping has limited effect on stability. It is shown that the location of the axial feed line of the top foil significantly influences the bearing load capacity and stability. The analysis further indicates that the static fluid film pressure distribution governs rotordynamic stability. Therefore selective shimming is introduced to tailor the unperturbed pressure distribution for improved stability. The required pattern is found via multi-objective optimization using the foil bearing supported rotor model. A critical mass parameter is introduced as a measure for stability, and a criterion for whirl instability onset is proposed. It is shown that with an optimally shimmed foil bearing, the critical mass parameter can be improved by more than two orders of magnitude. The optimum shim patterns are summarized for a variety of foil bearing geometries with different L/D ratios and different degrees of foil compliance in a first attempt to establish more general guidelines for stable foil bearing design. At low compressibility (Λ < 2) the optimum shim patterns vary little with bearing geometry, thus a generalized shim pattern is proposed for low compressibility numbers.