Literatura académica sobre el tema "Indicateurs vibratoires"
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Artículos de revistas sobre el tema "Indicateurs vibratoires":
Delaunay, T., S. Courtin, B. Durr, E. Le Clézio y G. Despaux. "Analyse vibratoire : De l’identification d’un balourd à la classification des formes vibratoires de roulements et de moteurs". J3eA 22 (2023): 1018. http://dx.doi.org/10.1051/j3ea/20231018.
Jamal-Eddine, Abdul-Karim, Luca Lenti y Jean-François Semblat. "Aléa vibratoire dans les sols : indicateurs pertinents et classification simplifiée". Revue Française de Géotechnique, n.º 155 (2018): 4. http://dx.doi.org/10.1051/geotech/2018008.
Tesis sobre el tema "Indicateurs vibratoires":
Meuterlos, Maxime. "Développement de méthodes de normalisation des indicateurs de santé vibratoires pour la surveillance d'ensembles mécaniques basées sur les paramètres d’utilisation. Application à l’hélicoptère". Electronic Thesis or Diss., Lyon, INSA, 2023. http://www.theses.fr/2023ISAL0097.
The VHMS (Vibration Health Monitoring System) installed on helicopters plays a strategic role in increasing the safety of operators and passengers during flight. These systems consist of recording operational data during flight, particularly vibration-related data, and monitoring the integrity of mechanical components through indicators derived from signal processing. The basic principle is based on the assumption that the appearance of a failure mode generates a characteristic evolution of indicator values. However, one limitation of VHMS systems is the strong dependence of indicators on flight conditions, which can vary rapidly and complex for helicopters. These variations, which are difficult to control, can mask the signature of a mechanical failure, resulting in ambiguity in interpreting the origin of the observed indicator evolution. In this manuscript, normalization methods are developed to estimate normalized vibration indicators, which are insensitive to flight conditions. First, a review of normalization methods commonly used in the literature is presented. Second, a parametric statistical framework modeling vibration indicators is proposed based on cyclostationary modeling of the vibration signal. This parametric framework will be used to construct two approaches to normalizing vibration indicators. The first approach is based on clustering-classification, linking the helicopter flight phases to the statistics of the vibration indicator. Then, a second approach is based on the regression of quantile distribution parameters conditioned on flight parameters that explain the variability of health indicators. In parallel, a sensitivity analysis is conducted to identify these flight parameters
Kass, Souhayb. "Diagnostic vibratoire autonome des roulements". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI103.
The industrial and transportation sectors require more and more efficient and complex machines and installations increasing the risk of failure and disruption. This can lead to the immediate shutdown of a machine and disrupts the proper functioning of the entire production system. The diagnosis of industrial machines is essentially based on the monitoring of symptoms related to different degradation conditions. These symptoms can be derived from various sources of information, including vibration and acoustic signals. Nowadays, many effective techniques are well established, based on powerful tools offered by the theory of cyclostationary processes. The complexity of these tools requires an expert to use them and to interpret the results based on his/her experience. The continuous presence of the expert is expensive and difficult to achieve in practice. Condition indicators for rotating machines exist in the literature but they are conceived under the assumption of perfect operating conditions. They are limited, dispersed and generally not supported by theoretical frameworks. The main objective of this thesis is to reduce the use of human intervention by proposing strategies to design two optimal indicators that summarize diagnostic information into a scalar value. A distinction is made between two families in diagnosis: the case where prior information on the faults is known and the case where it is unknown. These indicators are designed to be used in an autonomous process without requiring human intervention, using statistical hypothesis tests. The capacity of these indicators is validated on real data and compared with other indicators from the literature in terms of detection performance
Hui, Yi. "Development and experimental validation of vibration based damage indicator on a specific twin-wall sandwich structure". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEC032.
Structural health monitoring (SHM) has attracted much attention in many engineering fields like civil, aeronautic, mechanical industry, etc. since it is important to monitor the healthy condition of the operational structure in order to avoid unpredicted structural failure which may have severe consequences. The four-level damage identification process: existence, localization, severity and prediction of damage evolution, can be partly realized if a suitable indicator is chosen. It exists different damage indicators whose application range of frequency spans from vibrational response at low frequencies to the ultrasonic regimes in the mega hertz range.The sandwich structures are widely used in various engineering applications due to its exceptionally high flexural stiffness-to-weight ratio compared to monocoque structures. In this thesis a specified twin-wall sandwich structure in polypropylene was studied and vibration-based indicators were designed by taking use of its relative high damping and propagation directivity characteristics. Numerical investigations on different damage scenarios (i.e., different types of defect and their combinations) and an associated discussion on the range of application were first carried out. Experimental configuration was easily realized with the help of a scanning laser doppler vibrometer (SLDV). Defect was successfully detected by the proposed indicators
Delcor, Laurianne. "Contribution à la modélisation du confort vibratoire et acoustique sous excitations multi-harmoniques en cabine d’hélicoptères". Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI042.
Helicopters are complex machines generating a significant amount of noise and vibration. It is therefore important for Airbus to be able to specify the discomfort to offer comfortable helicopters to their customers. The literature proposes a standard to quantify vibration comfort from acceleration measurements (ISO2631-1). Concerning noise, internal Airbus studies have been carried out and have shown that noise discomfort can be modelled as a function of loudness, acuity, tone and level in dB(G). Finally, there is no overall discomfort model linking the discomfort of simultaneous sound and vibration stimuli for application to the helicopter. This thesis aims to model global discomfort based on these tools. Several perceptual experiments aimed at evaluating the discomfort of vibratory stimuli in volunteers have been performed. They have shown that the ISO2631-1 standard provides a good estimate of vibratory discomfort. A modification of this standard taking into account the amplitude modulation of accelerations makes it possible to improve the predictive quality in the case of beating phenomena. Similar experiments have been performed in acoustics, where participants evaluated sound stimuli without and with hearing protection. In the first case, the discomfort model developed by Airbus remains valid. A simpler model based on loudness alone allows a better estimation of the sound discomfort. With hearing protectors, the estimation of discomfort is not as direct, the sound signals must first be filtered out by the attenuation of the protectors. This thesis has shown that for helicopter sounds, the attenuation values provided by the manufacturers are too optimistic. Objective attenuation measurements give lower values, in accordance with INRS recommendations. The sound signals are therefore filtered by the attenuations of the protectors provided by the manufacturers penalized according to the INRS. A model based on loudness alone makes it possible to estimate the sound discomfort under hearing protection. However, the coefficients of this model are different from the model obtained for listening without protection. Finally, volunteers estimated the global discomfort for noise and vibrations of helicopters played simultaneously. The results showed that a global discomfort model can be obtained from the noise discomfort indicators and the vibration discomfort indicators. This model is based on a linear regression to which a coupling term was added, in the form of the absolute value of the difference between the noise indicator and the vibration indicator. A simplified model makes it possible to dispense with vibration measurements at the seat and backrest and to estimate discomfort from noise measurements and foot accelerations for a given seat