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Статті в журналах з теми "Balance des harmoniques"
Román Segura, María del Socorro. "Proyecto ATG: Medio ambiente y afectaciones sociales a comunidades totonacas de Papantla, Veracruz, México." Clivajes. Revista de Ciencias Sociales, no. 9 (April 24, 2018): 153–69. http://dx.doi.org/10.25009/clivajes-rcs.v0i9.2545.
Повний текст джерелаДисертації з теми "Balance des harmoniques"
Abboud, Eddy. "Simulation, mastering, and reduction of vibrations and noises in electric car gearbox transmission systems." Thesis, Paris, HESAM, 2022. http://www.theses.fr/2022HESAE026.
Повний текст джерелаThe current architectures of hybrid or electric motorizations of motor vehicles include transmissions by gears at the electric motor's output to adapt the speed of rotation to that of the vehicle wheels. These gears are the source of vibrations that propagate through the solid state to the system housing, the acoustic source of radiated noise. These noises affect the user's comfort, mainly because they are not masked by the noise of the electric motor, which is very different from that of a conventional combustion engine. Therefore, controlling this noise is a significant challenge for today's car manufacturers. There are many sources of vibration in geared power transmissions. For example, the engine's output torque's acyclic nature leads to rotational speed fluctuations, and periodic variations in the meshing stiffness under torque produce a so-called parametric vibration excitation, which produces a characteristic whining noise. In this context, several manufacturers are currently studying the modeling of vibrations in gear transmission systems, intending to predict the appearance of the various noises and possibly adjust the system's design accordingly. This thesis aims to set up numerical models to represent the vibratory behavior of gear systems from the understanding of the interaction between mating gears, to the dynamic presentation of a complete gearbox. Several points have been addressed in this context: a parametric study is performed on the differential equation of the interaction between gears to analyze and predict their dynamic behavior. In parallel, a method for calculating the vibrations due to the meshing process using the harmonic balancing method (HBM) is proposed. Finally, a method for calculating a reduced gearbox model under gear excitation is presented
Jaumouillé, Vincent. "Dynamique des structures à interfaces non linéaires : Extension des techniques de balance harmonique." Phd thesis, Ecole Centrale de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00670283.
Повний текст джерелаGuedeney, Thomas. "Modélisation des interactions rotor-stator par une méthode d'équilibrage harmonique." Phd thesis, Ecole Centrale de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00948101.
Повний текст джерелаHijazi, Abdallah. "Implementation of harmonic balance reduce model order equation." Thesis, Limoges, 2015. http://www.theses.fr/2015LIMO0139/document.
Повний текст джерелаMOR recently became a well-known research field, due to the interest that it shows in reducing the system, which saves time, memory, and CPU cost for CAD tools. This field contains two branches, linear and nonlinear MOR, the linear MOR is a mature domain with well-established theory and numerical techniques. Meanwhile, nonlinear MOR domain is still stammering, and so far it didn’t show good and successful results in electrical circuit simulation. Some improvements however started to pop-up recently, and research is still going on this field because of the help that it can give to the contemporary simulators, especially with the growth of the electronic chips in terms of size and complexity due to industrial demands towards integrating systems on the same chip. A significant contribution in the MOR technique of HB solution has been proposed a decade ago by E. Gad and M. Nakhla. The technique has shown to provide a substantial system dimension reduction while preserving the precision of the output in steady state analysis. This MOR method uses the technique of projection via Krylov, and it preserves the passivity of the system. However, it suffers a number of important limitations in the construction of the pre-conditioner matrix which is ought to reduce the system. The main limitation is the necessity for explicit factorization as a power series of the equation of the nonlinear devices. This makes the technique difficult to apply in general purpose simulator conditions. This thesis will review the aspects of the nonlinear model order reduction technique for harmonic balance equations, and it will study solutions to overcome the above mentioned limitations, in particular using numerical differentiation approaches
Viana, Serra Villa Cristiano. "Dynamique non linéaire des rotors : Applications numériques et expérimentales à un rotor flexible." Ecully, Ecole centrale de Lyon, 2005. http://bibli.ec-lyon.fr/exl-doc/cvilla.pdf.
Повний текст джерелаThis thesis deals with the dynamic behavior of rotating machinery containing the parts whose behavior is described by non linear laws. The first goal of this research is to implement methods of non linear analysis in order to solve the equations of motion of the system. Secondly, experimental studies are made with a test rig and the results are used to update a numeric model. The rotor is represented by a finite element model. To model the bearings, three models with different levels of complexity are presented, and a model where the kinematics of the rolling elements is adopted. The type of motion of interest is the steady state vibration, and to obtain this kind of solution it is advisable to use a frequential method like the Harmonic Balance Method Alternating Frequency Time (HBM AFT). This method can be implemented with an exact condensation strategy to reduce the computational time. The HBM AFT method is validated by comparing with a direct integration of a non linear Jeffcott rotor
Gomar, Adrien. "Méthode d'Équilibrage Harmonique Multi-Frequentielle pour la Simulation des Doublets d'Hélices Contra-Rotatives : application à l'aéroélasticité." Thesis, Paris, ENSAM, 2014. http://www.theses.fr/2014ENAM0010/document.
Повний текст джерелаComputational Fluid Dynamics (CFD) has allowed the optimization of many configurations among which aircraft engines. In the aeronautical industry, CFD is mostly restricted to steady approaches due to the high computational cost of unsteady simulations. Nevertheless, the flow field across the rotating parts of aircraft engines, namely turbomachinery blades, is essentially periodic in time. Years ago, Fourier-based time methods have been developed to take advantage of this time periodicity. However, they are, for the most part, restricted to mono-frequential flow fields. This means that only a single base-frequency and its harmonics can be considered. Recently, a multi-frequential Fourier-based time method, namely the multi-frequential Harmonic Balance (HB), has been developed and implemented into the elsA CFD code, enabling new kinds of applications as, for instance, the aeroelasticity of multi-stage turbomachinery.The present PhD thesis aims at applying the HB approach to the aeroelasticity of a new type of aircraft engine: the contra-rotating open rotor. The method is first validated on analytical, linear and non-linear numerical test problems. Two issues are raised, which prevent the use of such an approach on arbitrary aeroelastic configurations: the conditioning of the multi-frequential HB source term and the convergence of the method. Original methodologies are developed to improve the condition number of the simulations and to provide a priori estimates of the number of harmonics required to achieve a given convergence level. The HB method is then validated on a standard configuration for turbomachinery aeroelasticity. The results are shown to be in fair agreement with the experimental data. The applicability of the method is finally demonstrated for aeroelastic simulations of contra-rotating open rotors
Charleux, Damien. "Etude des effets de la friction en pied d'aube sur la dynamique des roues aubagées." Ecully, Ecole centrale de Lyon, 2006. http://bibli.ec-lyon.fr/exl-doc/dcharleux.pdf.
Повний текст джерелаThis PhD dissertation is devoted to the study of blade/disk attachments in turbomachinery with a particular emphasis on the impact of friction on the dynamic response of bladed disks. The problem was tackled both experimentally and numerically and the developed tools can be seen as a contribution to the prevention of high cycle fatigue failures due to the aerodynamic flow inhomogeneities
Kharyton, Vsevolod. "Faults detection in blades of an aviation engine in operation." Ecully, Ecole centrale de Lyon, 2009. http://www.theses.fr/2009ECDL0006.
Повний текст джерелаThe general aim of the study is to offer mathematical model of the process, which can allow crack identification in the compressor or turbine blade of aircraft gas-turbine engine in operation. Within the frameworks of this goal cracked blade non-linear dynamic model was elaborated and introduced to the global model of the bladed disk. Crack induced non-linearity was taken into account applying contact analysis elements in conjunction with harmonic balance method. For system size reduction the sub-structuring methodology using fixed-interface method was applied. It supposes the crack location to be considered as interface between two dependent, in this case, substructures. Such approach was applied to the both uncoupled cracked blade and bladed disk models. Also considering uncoupled cracked blade the centrifugal forces effect was examined. It was concluded, that depending on crack properties (location and size), it will be enough to use the linear crack presence formulation supposing crack to be always open (initial gap). During simulation of the bladed disk forced response containing cracked blade the effect of blade mistuning was simulated. Simulation results shown that at certain level of mistuning it becomes impossible to separate cracked blade response. Furthermore such crack detectability decreases with absence of cracked blade frequency localization. The last one phenomenon is very important diagnostic sign, which simplifies cracked blade detection at almost all cases. The last phase of the work was devoted to simulation of blade tip-timing method application for cracked blade identification. It consisted in blade arriving time generation, blade tip amplitudes reconstruction and bladed disk frequency response calculation on the base of measured (simulated) time data. Such approach allowed us to identify cracked blade in the same way as in frequency response analysis. Generally speaking, blade tip-timing method can be used as the part of engine health monitoring system for compressor or turbine blades dynamic performances monitoring
Safa, Mohamad. "Modélisation réduite de la pile à combustible en vue de la surveillance et du diagnostic par spectroscopie d'impédance." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00855160.
Повний текст джерелаRenault, Alexandre. "Calcul et optimisation d’absorbeurs pendulaires dans une chaîne de traction automobile." Thesis, Paris, ENSAM, 2018. http://www.theses.fr/2018ENAM0022.
Повний текст джерелаIn the context of the reduction of polluting emissions and fuel consumption of thermal engines of vehicles, automotive manufacturers try to reduce cylinder capacity and engine speed of rotation. These evolutions lead to significant increase of irregularities of rotation. The so-called centrifugal pendulum vibration absorber is a recent solution of mitigation of torsional vibrations in automotive powertrains. It acts as a mass damper tuned on the firing order of the engine and allows reduction of vibrations. However, strong non-linearities intrinsic to pendular systems cause a detuning of the device at large amplitude of motion resulting in a loss of performances. This thesis aims to improve the understanding and the behavior of the system in interaction with an automotive driveline. In support of classic time integration procedures, the nonlinear system is solved through the asymptotic numerical method coupled to the harmonic balance method. In addition, an original continuation of antiresonance method is proposed as well as some design rules derived from analytical developments. Experimental validation shows a significant enhancement of performances of the system