The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
S Jolivet - One of the best experts on this subject based on the ideXlab platform.
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experimental and numerical study of tooth finishing processes contribution to Gear Noise
Tribology International, 2016Co-Authors: S Jolivet, S Mezghani, J Isselin, El M MansoriAbstract:Abstract The contribution of Gear tooth flank surface micro-finish on Gear Noise has not yet been taken into consideration. This paper is devoted to study the simultaneous effect of tooth roughness and lubricant viscosity on automotive Gear vibrations. The vibrations performances were evaluated on an instrumented test rig under both dry and wet conditions. A non-destructive replication technique coupled to 3D optical measures was used to acquire the flanks topographies, which were characterized using multiscale decomposition. A three-dimensional finite element simulation of a helical Gear was performed to assess the micro-scales impact on Gear Noise. Numerical representative surfaces morphologies were introduced into the simulation and compared through the transmission error calculation. Results have shown Gear Noise dependence on tooth finishing processes.
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dependence of tooth flank finishing on powertrain Gear Noise
Journal of Manufacturing Systems, 2015Co-Authors: M. El Mansori, S Jolivet, S Mezghani, Benoit JourdainAbstract:Abstract Finishing processes can be used in order to reduce manufacturing errors on teeth flank surfaces. These surfaces are at the heart of the Gear meshing mechanics and thus should have an impact on Gear Noise. This paper addresses the issue of the impact tooth flank finishing on Noise and vibration. The topographic and vibratory performances of two finishing processes, grinding and powerhoning, were compared. Multiscale analysis through continuous wavelet decomposition was used in order to characterize the teeth surfaces as well as the vibration spectra of a powertrain transmission tested on an industrial bench in a wide range of rotational speeds and frequencies. Results show that flank finishing processes leave their signature on the teeth surfaces which impact the vibratory behavior of the Gear. Moreover, multiscale analysis approach allows the separation of vibration sources (meshing, environment, etc), and permits to quantify the impact of the choice of the finishing process.
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Evaluation of Tooth Surface Micro-Finishing on Gear Noise
Key Engineering Materials, 2015Co-Authors: S Jolivet, Sabeur Mezghani, M. El Mansori, J Isselin, Alain Giraudeau, Hassan ZahouaniAbstract:For automotive Gear manufacturers, reducing Gear Noise while maintaining the Gear load-carrying capacity as well as the wear resistance has become more and more important. Macro- and micro-geometrical defects have long been studied in order to explain the vibratory behavior of Gears. However, the contribution of the micro-scale roughness of the flanks, essential in the Gear contact mechanics, has not yet been fully understood.This paper addresses this issue where Gears were manufactured with two industrial finishing processes (grinding and power-honing) while having the same macro-scale characteristics. Tridimensional topographical features of teeth surface were hence measured using a three-dimensional white light interferometer. As manufactured surface topographies are highly complex, irregular, and multiscale, all the teeth surfaces were characterized in the entire wavelength band using a multiscale method based on wavelets transform. Vibration performances of the Gears were then tested on a single-stage low powertrain. Results demonstrate the influence of micro-roughness scales on vibrations amplitude.
El M Mansori - One of the best experts on this subject based on the ideXlab platform.
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experimental and numerical study of tooth finishing processes contribution to Gear Noise
Tribology International, 2016Co-Authors: S Jolivet, S Mezghani, J Isselin, El M MansoriAbstract:Abstract The contribution of Gear tooth flank surface micro-finish on Gear Noise has not yet been taken into consideration. This paper is devoted to study the simultaneous effect of tooth roughness and lubricant viscosity on automotive Gear vibrations. The vibrations performances were evaluated on an instrumented test rig under both dry and wet conditions. A non-destructive replication technique coupled to 3D optical measures was used to acquire the flanks topographies, which were characterized using multiscale decomposition. A three-dimensional finite element simulation of a helical Gear was performed to assess the micro-scales impact on Gear Noise. Numerical representative surfaces morphologies were introduced into the simulation and compared through the transmission error calculation. Results have shown Gear Noise dependence on tooth finishing processes.
Yueping Guo - One of the best experts on this subject based on the ideXlab platform.
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Potential for Landing Gear Noise Reduction on Advanced Aircraft Configurations
22nd AIAA CEAS Aeroacoustics Conference, 2016Co-Authors: Russell H. Thomas, Craig L. Nickol, Casey L. Burley, Yueping GuoAbstract:The potential of significantly reducing aircraft landing Gear Noise is explored for aircraft configurations with engines installed above the wings or the fuselage. An innovative concept is studied that does not alter the main Gear assembly itself but does shorten the main strut and integrates the Gear in pods whose interior surfaces are treated with acoustic liner. The concept is meant to achieve maximum Noise reduction so that main landing Gears can be eliminated as a major source of airframe Noise. By applying this concept to an aircraft configuration with 2025 entry-into-service technology levels, it is shown that compared to Noise levels of current technology, the main Gear Noise can be reduced by 10 EPNL dB, bringing the main Gear Noise close to a floor established by other components such as the nose Gear. The assessment of the Noise reduction potential accounts for design features for the advanced aircraft configuration and includes the effects of local flow velocity in and around the pods, Gear Noise reflection from the airframe, and reflection and attenuation from acoustic liner treatment on pod surfaces and doors. A technical roadmap for maturing this concept is discussed, and the possible drag increase at cruise due to the addition of the pods is identified as a challenge, which needs to be quantified and minimized possibly with the combination of detailed design and application of drag reduction technologies.
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Effects of Local Flow Variations on Landing Gear Noise Prediction and Analysis
Journal of Aircraft, 2010Co-Authors: Yueping GuoAbstract:This paper discusses a study on the local flows in the vicinity of aircraft landing Gear. Local flows for various aircraft types at various operation conditions are extracted from a computational fluid dynamics database and analyzed to reveal parametric trends of the local flows. It is shown that, for wing-mounted Gear, the circulation around the high-lift wing induces a flow under the wing in the opposite direction to the freestream flow and, hence, makes the local flow velocity lower than the freestream velocity. For fuselage-mounted Gear, the trends are opposite; the local flow velocity for nose Gear is usually slightly higher than the freestream. For all Gear, it is shown that the local flow velocity is a decreasing function of the aircraft angle of attack. Based on these features, a simple reduced-order model is developed, which correlates the local flow velocity to the freestream velocity, the aircraft angle of attack, the maximum aircraft takeoff weight, and the distance from the aircraft. All these parameters are readily available in practical applications, rendering the simple model suitable for landing Gear Noise prediction. Discussions are given on the effects of the local flow features on landing Gear Noise analysis and prediction with practical examples.
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A Study on Local Flow Variations for Landing Gear Noise Research
14th AIAA CEAS Aeroacoustics Conference (29th AIAA Aeroacoustics Conference), 2008Co-Authors: Yueping GuoAbstract:*This paper discusses a systematic study on the local flows in the vicinity of aircraft landing Gears with the objective of understanding the flow features, identifying their effects on landing Gear Noise generation and prediction and developing simple and efficient models to calculate the local flow velocity for Gear Noise prediction and analysis. To achieve this objective, local flows for various aircraft types and various operation conditions are extracted from a large CFD database and analyzed to reveal the parametric trends of the local flows as a function of parameters such as the aircraft angle of attack and landing Gear location. It is shown that for wing mounted Gears, the local flows are strongly affected by the high lift system; the circulation around the high lift wing induces a flow under the wing in opposite direction to the free stream flow, and hence, makes the local flow velocity lower than the free stream velocity, by as much as 25 percent at the Gear locations. The local velocities are shown to increase monotonically from their minimum values close to the lower surface of the wing to the free stream velocity as the distance from the wing increases. However, for fuselage mounted Gears, the trends are opposite; the local flow velocity for nose Gears is usually slightly higher than the free stream and it achieves its maximum close to the lower surface of the fuselage with decreasing amplitude with the distance from the fuselage. This is because the nose Gears are located in a flow acceleration region downstream of the stagnation point on the nose cone surface, which is approximately defined here as the minimum velocity point. For all Gears, it is shown that the local flow velocity is a decreasing function of the aircraft angle of attack. For wing mounted Gears, this is due to the increased lift of the wing at large angles of attack, while for nose Gears, increasing angles of attack move the stagnation point downstream towards to nose Gears, reducing the velocity at the Gear location. Based on these flow features, a simple reduced-order model is developed, which correlates the local flow velocity to the free stream velocity, the aircraft angle of attack, the maximum aircraft takeoff weight and the distance from the aircraft. All these parameters are readily available in practical applications, rendering the simple model suitable for landing Gear Noise prediction. Some qualitative discussions are given on the effects of the local flow features on landing Gear Noise analysis and prediction.
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RETRACTED: A component-based model for aircraft landing Gear Noise prediction
Journal of Sound and Vibration, 2008Co-Authors: Yueping GuoAbstract:This paper follows the general formulation of aircraft landing Gear Noise prediction to develop a component-based model, incorporating scaling laws of the theory of aerodynamic Noise generation and correlations of these scaling laws with currently available test data. The method decomposes the landing Gear Noise into three spectral components, respectively, for the low, the mid and the high frequencies, which corresponds to cataloging the parts in the landing Gear assembly into three groups, namely, the wheels, the main struts, and the small details. For all three spectral components, models are presented for their spectra, far-field directivities and amplitudes. The spectral characteristics of the three components are defined by normalized spectra, as functions of the Strouhal numbers based on the respective length scales of the three groups of parts in the landing Gear assembly. Individual directivity factors are also presented for the three spectral components, with the low-frequency component having the smallest variations with emission angle and the high-frequency component having the largest variations. The amplitudes of the three spectral components are correlated to parameters unique to each group of landing Gear parts, with the low- and mid-frequency Noise essentially characterized by the physical dimensions of the wheels and the main struts, respectively, and the high-frequency Noise, whose generation is associated with a large number of small details in practical landing Gears, defined by a complexity factor. Quantities that affect this complexity factor are discussed and an empirical model is proposed for practical applications. The prediction model is validated by wing tunnel test data for an isolated Boeing 737 landing Gear. In this case, the predictions agree well with data, both in parametric trends and in absolute Noise levels.
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A Semi-Empirical Model for Aircraft Landing Gear Noise Prediction
12th AIAA CEAS Aeroacoustics Conference (27th AIAA Aeroacoustics Conference), 2006Co-Authors: Yueping GuoAbstract:This paper presents an empirical model for landing Gear Noise prediction. The model is based on scaling laws of the theory of aerodynamic Noise generation and correlations of these scaling laws with currently available test data. The method decomposes the landing Gear Noise into three spectral components respectively for the low, the mid and the high frequencies, which corresponds to cataloguing the parts in the landing Gear assembly into three groups, namely, the wheels, the main struts and the small details. For all three spectral components, empirical models are derived for their spectral shapes, far field directivities and Noise amplitudes. The spectral shapes are defined by normalized spectra, as functions of the Strouhal numbers based on the respective length scales of the three groups of parts in the landing Gear. Individual directivity factors are also derived for the three spectral components, with the low frequency component having the smallest variations with emission angle and the high frequency component having the largest variations. Directivity due to installation effects is also modeled. The amplitudes of the three spectral components are correlated to parameters unique to each group of landing Gear parts, with the low and mid frequency Noise essentially characterized by the physical dimensions of the wheels and the main struts, respectively, and the high frequency Noise, whose generation is associated with a large number of small details in practical landing Gears, defined by a complexity factor. Quantities that affect this complexity factor are discussed and an empirical model is given for practical applications. The prediction model is validated by wing tunnel test data for an isolated Boeing 737 landing Gear and by flight test data for the Boeing 777 airplane. In both cases, the predictions agree well with data, both in parametric trends and in absolute Noise levels.
Hassan Zahouani - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of Tooth Surface Micro-Finishing on Gear Noise
Key Engineering Materials, 2015Co-Authors: S Jolivet, Sabeur Mezghani, M. El Mansori, J Isselin, Alain Giraudeau, Hassan ZahouaniAbstract:For automotive Gear manufacturers, reducing Gear Noise while maintaining the Gear load-carrying capacity as well as the wear resistance has become more and more important. Macro- and micro-geometrical defects have long been studied in order to explain the vibratory behavior of Gears. However, the contribution of the micro-scale roughness of the flanks, essential in the Gear contact mechanics, has not yet been fully understood.This paper addresses this issue where Gears were manufactured with two industrial finishing processes (grinding and power-honing) while having the same macro-scale characteristics. Tridimensional topographical features of teeth surface were hence measured using a three-dimensional white light interferometer. As manufactured surface topographies are highly complex, irregular, and multiscale, all the teeth surfaces were characterized in the entire wavelength band using a multiscale method based on wavelets transform. Vibration performances of the Gears were then tested on a single-stage low powertrain. Results demonstrate the influence of micro-roughness scales on vibrations amplitude.
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Numerical Simulation of Tooth Surface Finish Effects on Gear Noise
Volume 1: Applied Mechanics; Automotive Systems; Biomedical Biotechnology Engineering; Computational Mechanics; Design; Digital Manufacturing; Educati, 2014Co-Authors: Samuel Jolivet, Sabeur Mezghani, M. El Mansori, Hassan ZahouaniAbstract:Due to the rapid development of electric and hybrid motorisations, Gear manufacturers have encountered an increasing need to create high level quality Gear flanks. While the main goals are to increase the load-carrying capacity and the wear resistance, reducing Gear Noise has become more and more important. To answer this, macro- and micro-geometry defects have long been studied as well as their effect in amplifying the vibrations of Gears. However, the impact of tooth flanks micro-scale roughness on Gear Noise has not well been studied and understood, even though the teeth surface contacts are essential in the Gear mechanics.This paper aimed to discriminate the influence of the tooth finishing process (grinding, powerhoning) on single stage spur Gear Noise. A two-dimensional finite-element simulation model of a one-stage Gear system was hence developed. The transmission system was composed of two identical loaded Gears with one degree of freedom. Topological features of teeth surfaces finished by grinding and powerhoning were measured with a three-dimensional white light interferometer. These real topographic profiles of the tooth surfaces were integrated in the model. The meshing stiffness was determined as an output of this dynamic model. It is a parameter directly linked to the acoustic behaviour of the Gear. Results show that Gear Noise could be reduced by the right choice of the finishing process kinematic.Copyright © 2014 by ASME
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Gear Noise behavior induced by their topological quality
Surface Topography: Metrology and Properties, 2013Co-Authors: Samuel Jolivet, Sabeur Mezghani, M. El Mansori, Hassan ZahouaniAbstract:The upcoming fuel economy standards will result in the rapid development of electric or hybrid vehicles. Such regulatory demands will affect transmission design, which is currently driving changes in the number, type, size and quality levels of Gears. Thus, Gear manufacturers need to create high quality Gear flanks with special topological modifications. The most important objectives are to increase the load-carrying capacity of Gears and also to reduce the Gear Noise behavior. The teeth surface is at the heart of Gear meshing mechanics and is one of the main elements in the generation of Noise. The most common Gear wear mechanisms are micro-pitting, pitting and spalling, which often occur on teeth surface during the early stage of failure. This study aims to identify the scale effect of pitting defects of Gear teeth surface on the acoustics response of a spur Gear pair. Consequently, we have developed a two-dimensional finite-element simulation model of a one-stage Gear system. The transmission system was composed of two identical spur Gears with one degree of freedom. Pitting defects versus topological features at different scales were modeled on the Gear tooth flanks. To quantify their impact on Gear Noises and vibrations, we used contact stiffness as our criteria because it is directly linked to Gear Noise. The prevalence of the Gear quality and its topological features on power density and sound issues are computed and discussed in this paper.
J Isselin - One of the best experts on this subject based on the ideXlab platform.
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experimental and numerical study of tooth finishing processes contribution to Gear Noise
Tribology International, 2016Co-Authors: S Jolivet, S Mezghani, J Isselin, El M MansoriAbstract:Abstract The contribution of Gear tooth flank surface micro-finish on Gear Noise has not yet been taken into consideration. This paper is devoted to study the simultaneous effect of tooth roughness and lubricant viscosity on automotive Gear vibrations. The vibrations performances were evaluated on an instrumented test rig under both dry and wet conditions. A non-destructive replication technique coupled to 3D optical measures was used to acquire the flanks topographies, which were characterized using multiscale decomposition. A three-dimensional finite element simulation of a helical Gear was performed to assess the micro-scales impact on Gear Noise. Numerical representative surfaces morphologies were introduced into the simulation and compared through the transmission error calculation. Results have shown Gear Noise dependence on tooth finishing processes.
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Evaluation of Tooth Surface Micro-Finishing on Gear Noise
Key Engineering Materials, 2015Co-Authors: S Jolivet, Sabeur Mezghani, M. El Mansori, J Isselin, Alain Giraudeau, Hassan ZahouaniAbstract:For automotive Gear manufacturers, reducing Gear Noise while maintaining the Gear load-carrying capacity as well as the wear resistance has become more and more important. Macro- and micro-geometrical defects have long been studied in order to explain the vibratory behavior of Gears. However, the contribution of the micro-scale roughness of the flanks, essential in the Gear contact mechanics, has not yet been fully understood.This paper addresses this issue where Gears were manufactured with two industrial finishing processes (grinding and power-honing) while having the same macro-scale characteristics. Tridimensional topographical features of teeth surface were hence measured using a three-dimensional white light interferometer. As manufactured surface topographies are highly complex, irregular, and multiscale, all the teeth surfaces were characterized in the entire wavelength band using a multiscale method based on wavelets transform. Vibration performances of the Gears were then tested on a single-stage low powertrain. Results demonstrate the influence of micro-roughness scales on vibrations amplitude.
