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http://hdl.handle.net/10985/9672
An expert system to characterise the surfaces morphological properties according to their tribological functionalities: The relevance of a pair of roughness parameters
BIGERELLE, Maxence; NAJJAR, Denis; MATHIA, Thomas; IOST, Alain; COOREVITS, Thierry; ANSELME, Karine
Knowing that a surface or profile can be characterized by numerous roughness parameters, the objective of this investigation was to present a methodology which aims to determine quantitatively and without preconceived opinion the most relevant pair of roughness parameters that describe an abraded surface. The methodology was firstly validated on simulated fractal profiles having different amplitudes and Hölder exponents and it was secondly applied to characterise different worn regions of a retrieved metallic femoral head articulated against an ultra-high molecular weight polyethylene (UHMWPE) acetabular cup containing an embedded metallic fibber into its surface. The methodology consists in combining the recent Bootstrap method with the usual discriminant analysis. It was validated on simulated fractal profiles showing that, among more than 3000 pairs tested, the total amplitude Rt and the fractal dimension Δ is the most relevant pair of roughness parameters; parameters corresponding to the variables modulated in the analytical expression of the fractal function. The application of this methodology on a retrieved metallic femoral head shows that the most relevant pair of parameters for discriminating the different investigated worn regions is the arithmetic roughness parameter Ra paired with the mean peak height Rpm. This methodology finally helps in a better understanding of the scratch mechanism of this orthopedic bearing component.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10985/96722013-01-01T00:00:00ZBIGERELLE, MaxenceNAJJAR, DenisMATHIA, ThomasIOST, AlainCOOREVITS, ThierryANSELME, KarineKnowing that a surface or profile can be characterized by numerous roughness parameters, the objective of this investigation was to present a methodology which aims to determine quantitatively and without preconceived opinion the most relevant pair of roughness parameters that describe an abraded surface. The methodology was firstly validated on simulated fractal profiles having different amplitudes and Hölder exponents and it was secondly applied to characterise different worn regions of a retrieved metallic femoral head articulated against an ultra-high molecular weight polyethylene (UHMWPE) acetabular cup containing an embedded metallic fibber into its surface. The methodology consists in combining the recent Bootstrap method with the usual discriminant analysis. It was validated on simulated fractal profiles showing that, among more than 3000 pairs tested, the total amplitude Rt and the fractal dimension Δ is the most relevant pair of roughness parameters; parameters corresponding to the variables modulated in the analytical expression of the fractal function. The application of this methodology on a retrieved metallic femoral head shows that the most relevant pair of parameters for discriminating the different investigated worn regions is the arithmetic roughness parameter Ra paired with the mean peak height Rpm. This methodology finally helps in a better understanding of the scratch mechanism of this orthopedic bearing component.Influence of the Manufacturing Process of a Claw-Pole Alternator on its Stator Shape and Acoustic Noise
http://hdl.handle.net/10985/11835
Influence of the Manufacturing Process of a Claw-Pole Alternator on its Stator Shape and Acoustic Noise
TAN-KIM, Antoine; HAGEN, Nicolas; LANFRANCHI, Vincent; CLENET, Stéphane; COOREVITS, Thierry; MIPO, Jean-Claude; LEGRANGER, Jerome; PALLESCHI, Frédéric
This paper shows the influence of the manufacturing process of a claw-pole alternator on its acoustic noise. First, the stator welds and the assembly of the stator in the brackets are linked to deformations of the inner diameter of the stator. Then, the influences of these deformations on the magnetic forces and the subsequent acoustic noise are investigated. Results show that the deformations caused by the manufacturing process significantly increase the sound power level of particular orders.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10985/118352017-01-01T00:00:00ZTAN-KIM, AntoineHAGEN, NicolasLANFRANCHI, VincentCLENET, StéphaneCOOREVITS, ThierryMIPO, Jean-ClaudeLEGRANGER, JeromePALLESCHI, FrédéricThis paper shows the influence of the manufacturing process of a claw-pole alternator on its acoustic noise. First, the stator welds and the assembly of the stator in the brackets are linked to deformations of the inner diameter of the stator. Then, the influences of these deformations on the magnetic forces and the subsequent acoustic noise are investigated. Results show that the deformations caused by the manufacturing process significantly increase the sound power level of particular orders.A new approach of the Oliver and Pharr model to fit the unloading curve from instrumented indentation testing
http://hdl.handle.net/10985/11966
A new approach of the Oliver and Pharr model to fit the unloading curve from instrumented indentation testing
KOSSMAN, Stephania; COOREVITS, Thierry; IOST, Alain; CHICOT, Didier
The unloading part of a load–displacement curve from instrumented indentation tests is usually approximated by a power law (Oliver and Pharr model), where the load is the dependent variable. This approach generally fits well the data. Nevertheless, the convergence is occasionally quite questionable. In this regard, we propose a different approach for the Oliver and Pharr model, called the inverted approach, since it assigns the displacement as the dependent variable. Both models were used to fit the unloading curves from nanoindentation tests on fused silica and aluminum, applying a general least squares procedure. Generally, the inverted methodology leads to similar results for the fitting parameters and the elastic modulus (E) when convergence is achieved. Nevertheless, this approach facilitates the convergence, because it is a better conditioned problem. Additionally, by Monte Carlo simulations we found that robustness is improved using the inverted approach, since the estimation of E is more accurate, especially for aluminum.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10985/119662017-01-01T00:00:00ZKOSSMAN, StephaniaCOOREVITS, ThierryIOST, AlainCHICOT, DidierThe unloading part of a load–displacement curve from instrumented indentation tests is usually approximated by a power law (Oliver and Pharr model), where the load is the dependent variable. This approach generally fits well the data. Nevertheless, the convergence is occasionally quite questionable. In this regard, we propose a different approach for the Oliver and Pharr model, called the inverted approach, since it assigns the displacement as the dependent variable. Both models were used to fit the unloading curves from nanoindentation tests on fused silica and aluminum, applying a general least squares procedure. Generally, the inverted methodology leads to similar results for the fitting parameters and the elastic modulus (E) when convergence is achieved. Nevertheless, this approach facilitates the convergence, because it is a better conditioned problem. Additionally, by Monte Carlo simulations we found that robustness is improved using the inverted approach, since the estimation of E is more accurate, especially for aluminum.The effect of punching on electrical machine
http://hdl.handle.net/10985/20059
The effect of punching on electrical machine
EL YOUSSEF, Mohamad; BENABOU, AbdelKader; COOREVITS, Thierry; VAN GORP, Adrien; CLENET, Stéphane; FAVEROLLE, Pierre; MIPO, Jean-Claude; LAVALLEY, Yannick; LECUPPE, Thomas
This work enlightens the impact of punching on a specific stator performances. Two specimens type are withdrawn from a M330A35 punched lamination sheet. One type represents a closed magnetic circuit while the other represents two parts. Magnetic measurements are performed on both types. Measurements are compared with those performed on specimens cut by WEDM. The specific purpose of this paper is to investigate the impact of punching in presence of air gap which exist in electrical machines between rotor and stator. Therefore a dedicated device is developed in order to control airgap perfectly and FEM simulations are also presented to make results more accurate.
Tue, 01 Jan 2019 00:00:00 GMThttp://hdl.handle.net/10985/200592019-01-01T00:00:00ZEL YOUSSEF, MohamadBENABOU, AbdelKaderCOOREVITS, ThierryVAN GORP, AdrienCLENET, StéphaneFAVEROLLE, PierreMIPO, Jean-ClaudeLAVALLEY, YannickLECUPPE, ThomasThis work enlightens the impact of punching on a specific stator performances. Two specimens type are withdrawn from a M330A35 punched lamination sheet. One type represents a closed magnetic circuit while the other represents two parts. Magnetic measurements are performed on both types. Measurements are compared with those performed on specimens cut by WEDM. The specific purpose of this paper is to investigate the impact of punching in presence of air gap which exist in electrical machines between rotor and stator. Therefore a dedicated device is developed in order to control airgap perfectly and FEM simulations are also presented to make results more accurate.Experimental study of a six new ball-burnishing strategies effects on the Al-alloy flat surfaces integrity enhancement
http://hdl.handle.net/10985/12000
Experimental study of a six new ball-burnishing strategies effects on the Al-alloy flat surfaces integrity enhancement
AMDOUNI, Hatem; BOUZAIENE, Hassen; MONTAGNE, Alex; VAN GORP, Adrien; COOREVITS, Thierry; NASRI, Mustapha; IOST, Alain
Abstract: In the literature, the most studies conducted on the flat surface ball-burnishing process have been focused on the most important classical factors like burnishing speed, lateral feed, and the ball-burnishing load or pressure on the treated surfaces integrity enhancement. In this research, ballburnishing strategies are studied as a new ball-burnishing factor. The aim of this research is to show the improvement of the flat surface integrity of 2017A-T451 aluminum alloy using six new ball-burnishing strategies. Ball-burnishing tests were conducted in two passes using the recommended values of the ball-burnishing factors (the penetration depth ab is 40 μm, the linear ball-burnishing speed Vb is 500 mm/min and a lateral feed f of 0.2 mm). Two ball-burnishing strategies in two successive and perpendicular passes to the machining direction and four ball-burnishing strategies in two crossed passes have been designed and tested to improve the flat surfaces integrity of the samples. The characterization and the micrographic observations of the ball-burnished surfaces show that using the best ball-burnishing strategy leads to a great enhancement in surface quality. The latter is predicted by a gain in average roughness Ra of 81 %, an improvement in the mean spacing of profile irregularities Sm of 34 %, an enhancement in surface Nano-hardness HIT of 17 %, and sub-layer hardness betterment up to a depth of 500 μm.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10985/120002017-01-01T00:00:00ZAMDOUNI, HatemBOUZAIENE, HassenMONTAGNE, AlexVAN GORP, AdrienCOOREVITS, ThierryNASRI, MustaphaIOST, AlainAbstract: In the literature, the most studies conducted on the flat surface ball-burnishing process have been focused on the most important classical factors like burnishing speed, lateral feed, and the ball-burnishing load or pressure on the treated surfaces integrity enhancement. In this research, ballburnishing strategies are studied as a new ball-burnishing factor. The aim of this research is to show the improvement of the flat surface integrity of 2017A-T451 aluminum alloy using six new ball-burnishing strategies. Ball-burnishing tests were conducted in two passes using the recommended values of the ball-burnishing factors (the penetration depth ab is 40 μm, the linear ball-burnishing speed Vb is 500 mm/min and a lateral feed f of 0.2 mm). Two ball-burnishing strategies in two successive and perpendicular passes to the machining direction and four ball-burnishing strategies in two crossed passes have been designed and tested to improve the flat surfaces integrity of the samples. The characterization and the micrographic observations of the ball-burnished surfaces show that using the best ball-burnishing strategy leads to a great enhancement in surface quality. The latter is predicted by a gain in average roughness Ra of 81 %, an improvement in the mean spacing of profile irregularities Sm of 34 %, an enhancement in surface Nano-hardness HIT of 17 %, and sub-layer hardness betterment up to a depth of 500 μm.Influence of the Manufacturing Process of a Claw-Pole Alternator on Its Stator Shape and Acoustic Noise
http://hdl.handle.net/10985/12995
Influence of the Manufacturing Process of a Claw-Pole Alternator on Its Stator Shape and Acoustic Noise
TAN-KIM, Antoine; HAGEN, Nicolas; LANFRANCHI, Vincent; CLENET, Stéphane; COOREVITS, Thierry; MIPO, Jean-Claude; LEGRANGER, Jerome; PALLESCHI, Frédéric
This paper shows the influence of the manufacturing process of a claw-pole alternator on its acoustic noise. First, the stator welds and the assembly of the stator in the brackets are linked to deformations of the inner diameter of the stator. Then, the influences of these deformations on the magnetic forces and the subsequent acoustic noise are investigated. Results show that the deformations caused by the manufacturing process significantly increase the sound power level of particular orders.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10985/129952017-01-01T00:00:00ZTAN-KIM, AntoineHAGEN, NicolasLANFRANCHI, VincentCLENET, StéphaneCOOREVITS, ThierryMIPO, Jean-ClaudeLEGRANGER, JeromePALLESCHI, FrédéricThis paper shows the influence of the manufacturing process of a claw-pole alternator on its acoustic noise. First, the stator welds and the assembly of the stator in the brackets are linked to deformations of the inner diameter of the stator. Then, the influences of these deformations on the magnetic forces and the subsequent acoustic noise are investigated. Results show that the deformations caused by the manufacturing process significantly increase the sound power level of particular orders.LNE Activies in Nanometrology: flatness reference calibration algorithm
http://hdl.handle.net/10985/7755
LNE Activies in Nanometrology: flatness reference calibration algorithm
LAHOUSSE, Ludovic; BORIPATKOSOL, Siriwan; LELEU, Stéphane; DAVID, Jean-Marie; DUCOURTIEUX, Sébastien; COOREVITS, Thierry; GIBARU, Olivier
The Laboratoire National de Métrologie et d’Essais (LNE) has developed an innovative ultra precision coordinate measuring machine [LAH07] traceable to the national length standard to measure three-dimensional objects with nanometric uncertainties (figure 1). The measuring range is 300 mm x 300 mm x 50 μm. The objective in term of uncertainty is to reach 30 nm in X and Y directions for a displacement of 300 mm and about few nanometers for a vertical displacement of 50 μm. On this machine, we use four capacitive sensors to measure the position along z direction. These sensors target the flat surface of cylinders (300 mm diameter) used as flatness references. To measure the shape of these aluminum references with nanometric uncertainties, we propose a measurement method based on a propagation process in which we introduce an angular measurement to compensate the curvature error inherent in this method. The measurement process uses the same sensor technology (capacitive sensor) we use on the machine. This paper presents the measurement method, its validation and the first results.
Tue, 01 Jan 2008 00:00:00 GMThttp://hdl.handle.net/10985/77552008-01-01T00:00:00ZLAHOUSSE, LudovicBORIPATKOSOL, SiriwanLELEU, StéphaneDAVID, Jean-MarieDUCOURTIEUX, SébastienCOOREVITS, ThierryGIBARU, OlivierThe Laboratoire National de Métrologie et d’Essais (LNE) has developed an innovative ultra precision coordinate measuring machine [LAH07] traceable to the national length standard to measure three-dimensional objects with nanometric uncertainties (figure 1). The measuring range is 300 mm x 300 mm x 50 μm. The objective in term of uncertainty is to reach 30 nm in X and Y directions for a displacement of 300 mm and about few nanometers for a vertical displacement of 50 μm. On this machine, we use four capacitive sensors to measure the position along z direction. These sensors target the flat surface of cylinders (300 mm diameter) used as flatness references. To measure the shape of these aluminum references with nanometric uncertainties, we propose a measurement method based on a propagation process in which we introduce an angular measurement to compensate the curvature error inherent in this method. The measurement process uses the same sensor technology (capacitive sensor) we use on the machine. This paper presents the measurement method, its validation and the first results.CALIBRATION OF CAPACITIVE SENSORS AND ELECTRONIC LEVELS FOR THE STRAIGHTNESS MEASUREMENTS USING MULTIPROBE METHOD
http://hdl.handle.net/10985/7746
CALIBRATION OF CAPACITIVE SENSORS AND ELECTRONIC LEVELS FOR THE STRAIGHTNESS MEASUREMENTS USING MULTIPROBE METHOD
BORIPATKOSOL, Siriwan; LELEU, Stéphane; COOREVITS, Thierry; GIBARU, Olivier
In this work, the straightness length 300 mm measurement under nanometer uncertainty. The proposed methodology represents a process known as propagation using the assumption of small displacement which leads to solving an overdetermined linear system. The experimental studies were carried out on the capacitive sensors and electronic levels. The least squares mathematic method is apply to calculate the optimal solution. This method requires taking into account the uncertainties of the two different types of sensors leads to method of weighted least squares. The first step is to calibrate the sensors and to estimate the effect on the calculated straightness.
Sat, 01 Jan 2011 00:00:00 GMThttp://hdl.handle.net/10985/77462011-01-01T00:00:00ZBORIPATKOSOL, SiriwanLELEU, StéphaneCOOREVITS, ThierryGIBARU, OlivierIn this work, the straightness length 300 mm measurement under nanometer uncertainty. The proposed methodology represents a process known as propagation using the assumption of small displacement which leads to solving an overdetermined linear system. The experimental studies were carried out on the capacitive sensors and electronic levels. The least squares mathematic method is apply to calculate the optimal solution. This method requires taking into account the uncertainties of the two different types of sensors leads to method of weighted least squares. The first step is to calibrate the sensors and to estimate the effect on the calculated straightness.An expert system to characterize the surface morphological properties according to their functionalities
http://hdl.handle.net/10985/10838
An expert system to characterize the surface morphological properties according to their functionalities
BIGERELLE, Maxence; MATHIA, Thomas; IOST, Alain; COOREVITS, Thierry; ANSELME, Karine
In this paper we propose a new methodology to characterize the morphological properties of a surface in relation with its functionality (tribological properties, surface coating adhesion, brightness, wettability…). We create a software based on experimental design and surface profile recording. Using an appropriate database structure, the roughness parameters are automatically computed at different scales. The surface files are saved in a hard disk directory and roughness parameters are computed at different scales. Finally, a statistical analysis system proposes the roughness parameter (or the pair of roughness parameters) that better describe(s) the functionality of the surface and the spatial scales at which the parameter(s) is (are) the more relevant.
Sat, 01 Jan 2011 00:00:00 GMThttp://hdl.handle.net/10985/108382011-01-01T00:00:00ZBIGERELLE, MaxenceMATHIA, ThomasIOST, AlainCOOREVITS, ThierryANSELME, KarineIn this paper we propose a new methodology to characterize the morphological properties of a surface in relation with its functionality (tribological properties, surface coating adhesion, brightness, wettability…). We create a software based on experimental design and surface profile recording. Using an appropriate database structure, the roughness parameters are automatically computed at different scales. The surface files are saved in a hard disk directory and roughness parameters are computed at different scales. Finally, a statistical analysis system proposes the roughness parameter (or the pair of roughness parameters) that better describe(s) the functionality of the surface and the spatial scales at which the parameter(s) is (are) the more relevant.Study of the Influence of the Fabrication Process Imperfections on the Performances of a Claw Pole Synchronous Machine Using a Stochastic Approach
http://hdl.handle.net/10985/10557
Study of the Influence of the Fabrication Process Imperfections on the Performances of a Claw Pole Synchronous Machine Using a Stochastic Approach
LIU, Sijun; MAC, Hung; CLENET, Stéphane; COOREVITS, Thierry; MIPO, Jean-Claude
In mass production, fabrication processes of electrical machines are not perfectly repeatable with time, leading to dispersions on the dimensions which are not equal to their nominal values. The issue is then to link the dispersions on the dimensions which are uncertain to the performances of electrical machines in order to evaluate their influence. To deal with uncertainty, there is a growing interest in the stochastic approach, which consists in modelling the uncertain parameters with random variables. In fact, this approach enables to quantify the influence of the variability of the uncertain parameters on the variability of the quantities of interest. In this paper, a stochastic approach coupled with a 3D Finite Element model is used to study the influence of the fabrication process imperfections like the rotor eccentricity and the stator deformation on the performances of a claw pole synchronous machine.
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10985/105572015-01-01T00:00:00ZLIU, SijunMAC, HungCLENET, StéphaneCOOREVITS, ThierryMIPO, Jean-ClaudeIn mass production, fabrication processes of electrical machines are not perfectly repeatable with time, leading to dispersions on the dimensions which are not equal to their nominal values. The issue is then to link the dispersions on the dimensions which are uncertain to the performances of electrical machines in order to evaluate their influence. To deal with uncertainty, there is a growing interest in the stochastic approach, which consists in modelling the uncertain parameters with random variables. In fact, this approach enables to quantify the influence of the variability of the uncertain parameters on the variability of the quantities of interest. In this paper, a stochastic approach coupled with a 3D Finite Element model is used to study the influence of the fabrication process imperfections like the rotor eccentricity and the stator deformation on the performances of a claw pole synchronous machine.