Pierre Dehombreux | Université de Mons (original) (raw)

Papers by Pierre Dehombreux

Research paper thumbnail of 3D projection of the LuGre friction model adapted to varying normal forces

Multibody System Dynamics

In this paper, we develop an adaptation of the LuGre friction model so as to allow the developmen... more In this paper, we develop an adaptation of the LuGre friction model so as to allow the development of the friction force and its application in any directions on systems subjected to varying normal forces. This is achieved by projecting a modified LuGre model adapted to varying normal forces in 3D along an arbitrary orthogonal system. Consequently, the direction of the friction force is automatically oriented in the correct direction, thus stick, stick-slip, and slip behavior can be represented in all directions. The projected friction model has the following friction features: stick-slip, presliding displacement, frictional lag, varying break-away force, viscous friction, Stribeck effect, and is adapted to varying normal forces. The equivalence of this projected LuGre model with the modified one is proven analytically. The friction model is then applied to simulate the friction on two mechanical systems. The first system consists of a cube sliding on a plane with a transition from ...

Research paper thumbnail of Equivalence criteria between mechanical environments

European journal of mechanical and environmental engineering, 1996

Research paper thumbnail of A Systematic Literature Review of Cutting Tool Wear Monitoring in Turning by Using Artificial Intelligence Techniques

Machines

In turning operations, the wear of cutting tools is inevitable. As workpieces produced with worn ... more In turning operations, the wear of cutting tools is inevitable. As workpieces produced with worn tools may fail to meet specifications, the machining industries focus on replacement policies that mitigate the risk of losses due to scrap. Several strategies, from empiric laws to more advanced statistical models, have been proposed in the literature. More recently, many monitoring systems based on Artificial Intelligence (AI) techniques have been developed. Due to the scope of different artificial intelligence approaches, having a holistic view of the state of the art on this subject is complex, in part due to a lack of recent comprehensive reviews. This literature review therefore presents 20 years of literature on this subject obtained following a Systematic Literature Review (SLR) methodology. This SLR aims to answer the following research question: “How is the AI used in the framework of monitoring/predicting the condition of tools in stable turning condition?” To answer this rese...

Research paper thumbnail of Experimental Measurement of Wear Indicators for Estimating the Tool Remaining Useful Life

I Remplacement optimal des outils coupants I Simulation de la dégradation des outils de coupe par... more I Remplacement optimal des outils coupants I Simulation de la dégradation des outils de coupe par un procédé gamma [3] I Utilisation et ajustement d’un modèle de Cox aux risques proportionnels pour prédire la durée de vie d’un outil coupant [1] I Vérification de la prédiction face à une nouvelle campagne expérimentale I Conception de la campagne expérimentale I Analyse de la qualité de la prédiction et de ses facteurs d’influence Context

Research paper thumbnail of Estimate of Cutting Tool Lifespan through Cox Proportional Hazards Model

IFAC-PapersOnLine, 2016

Abstract: An important proportion of the cost of machined mechanical elements emanates from the c... more Abstract: An important proportion of the cost of machined mechanical elements emanates from the cost of cutting tools inserts. A large part of these costs is due to improper maintenance decisions. In this paper, we demonstrate the use of a gamma process tool wear simulation for providing tool lifetimes at several cutting speeds. We show the use of a survival model (Cox Proportional Hazards model) on turning cutting inserts, using the cutting speed as covariate. Contrary to other approaches, the Proportional Hazards model is not used to produce the parameters of a reliability model, but the Mean Up Time is rather computed through the integration of the raw survival model reliability baseline. Additional simulated data is used to validate the model. The importance of a proper distribution of the PH model fitting data is highlighted by the experimental results.

Research paper thumbnail of Dynamic reliability degradation based models and maintenance optimization

M of industrial equipment is a lever to increase the efficiency and the productivity of industrie... more M of industrial equipment is a lever to increase the efficiency and the productivity of industries. An intelligent maintenance is achieved by determining the optimum preventive time to replace an item in order to minimize the costs and to increase the avaibility. In order to reach the optimum, one has to know the reliability and the mean residual lifetime of an item. The reliability R(t) is the probability that an item will perform a required function without failure under stated conditions for a stated period of time. This information may be obtained by three approaches that depend of the available data (figure 1)[1].

Research paper thumbnail of Singular Spectrum Analysis for Bearing Defect Detection

Journal of Vibration and Acoustics, 2011

In this work, singular spectrum analysis is employed to process vibration signals resulting from ... more In this work, singular spectrum analysis is employed to process vibration signals resulting from rolling bearings. A monitoring indicator is defined from the fact that the structure of a signal recorded from a bearing becomes more complex when the bearing becomes defective. This can be explained by the nonstationarity and the nonlinearity induced by the defect. The effects of operating parameters such as load and speed on the indicator are studied. Results demonstrate that the indicator defined in this paper is less sensitive to these parameters than the rms value, a traditional vibratory indicator.

Research paper thumbnail of Prediction of wheel wear in urban railway transport: comparison of existing models

Vehicle System Dynamics - VEH SYST DYN, 2007

One of the most important maintenance costs in tramway transport comes from wear of wheel profile... more One of the most important maintenance costs in tramway transport comes from wear of wheel profiles. In the highly competitive railway market, the prediction of wear is then a major concern of the constructors. In this article, we present and compare four models well adapted to tramway conditions, involving contacts on the rolling tread and on the flange with very different sliding and pressure conditions. Moreover, all models can be implemented from the natural outputs of the railway simulation packages classically used in industry for the dynamics design of the vehicles. The first one, proposed by Jendel, is based on the well-known Archard's wear model. Enblom continues Jendel's approach by taking into account the contribution of wheel deformation on the sliding velocity. The last two models, developed by Zobory, and Pearce and Sherratt, determine the wear from the energy dissipation in the contact area. The models are first compared on a theoretical basis and, for that p...

Research paper thumbnail of «Early Detection of Bearing Damage by Means of Decision Trees»

Journal of Automation, …, 2009

Research paper thumbnail of Analysis of the Performance of Operational Data Analysis Methods

Mechanical Systems and Signal Processing, 1996

ABSTRACT Operating data are measurements taken from a system under operating conditions. They con... more ABSTRACT Operating data are measurements taken from a system under operating conditions. They contain a combination of the system characteristics and generally unknown loading conditions. The scope of this paper is to describe several methods of investigating operational phenomena and to discuss some of their limitations. The use of transmissibilities, monophase representation of operating shapes and principle response analysis will be illustrated from results obtained from a noise-free 11 dof discrete system, or from industrial results obtained from measurements on the guiding system of a vehicle with tyres.

Research paper thumbnail of Optimain : plate-forme d'élaboration de stratégies de maintenance pour la gestion des systèmes complexes

Revue Française de Gestion Industrielle

Dans le cadre de cet article, nous présentons la plate-forme OPTIMAIN destinée à aider le gestion... more Dans le cadre de cet article, nous présentons la plate-forme OPTIMAIN destinée à aider le gestionnaire dans l'optimisation de la gestion de la maintenance de son système de production. OPTIMAIN s'oriente principalement vers l'élaboration de stratégies de maintenance de systèmes ...

Research paper thumbnail of An adaptive degradation-based maintenance model taking into account both imperfect adjustments and AGAN replacements

Quality and Reliability Engineering International

Research paper thumbnail of An adaptive opportunistic maintenance model based on railway track condition prediction

Research paper thumbnail of Comparaison des processus gamma et Wiener pour modéliser la dégradation de géométrie de voies ferroviaires

Congrès Lambda Mu 20 de Maîtrise des Risques et de Sûreté de Fonctionnement, 2016

Le but de cette communication est d'établir une comparaison des processus stochastiques gamma et ... more Le but de cette communication est d'établir une comparaison des processus stochastiques gamma et Wiener pour la modélisation de données relatives à des défauts de géométrie de sections d'une ligne ferroviaire située en Suède. Le processus gamma, de par son caractère monotone et selon la littérature, semble être utilisé de manière exclusive pour modéliser l'évolution de ce type de dégradation (Mercier et al., 2010). Toutefois l'étude de cas envisagée dans cet article comporte des évolutions de dégradation non monotones ; c'est-à-dire que le niveau de dégradation peut localement diminuer. Ce caractère non monotone peut être dû à des erreurs de mesure ou lié à des actions de maintenance mineure de nature différente (rectification du rail, remplacement des traverses, bourrage manuel du ballast). Afin de prendre en compte ce caractère non monotone, le processus de Wiener est donc également considéré. A partir des données disponibles, les deux processus sont estimés et simulés. Les deux modèles obtenus sont alors comparés sur base de l'évolution de leur espérance mathématique et de leur variance. Finalement, un modèle de durée de vie résiduelle est proposé pour ces deux processus en calculant la distribution des temps d'atteinte d'un seuil critique de dégradation de géométrie de voie. Les implications pratiques de cette étude viseront à émettre des recommandations sur le choix d'un processus stochastique pour modéliser des dégradations de géométrie de voie.

Research paper thumbnail of « Reliabilitix », un outil d'optimisation de la maintenance basé sur la fiabilité

d'une machine est primordiale. En effet, si un remplacement anticipé provoque des coûts d'interve... more d'une machine est primordiale. En effet, si un remplacement anticipé provoque des coûts d'intervention supplémentaires, l'attente de la défaillance de la machine peut avoir des conséquences bien plus importantes, non seulement par le surcoût direct et indirect des opérations de maintenance correctives, mais également par l'exposition aux risques majeurs qu'un défaut de maintenance peut entraîner. Ce dernier aspect pose le problème de la relation entre maintenance et risques, abordé dans d'autres contributions (Hadni, 2009). Dans cet article, nous nous limiterons à une optimisation de la maintenance basée sur la fiabilité, vis-à-vis de critères de coût et disponibilité. Cette approche est expliquée et illustrée depuis l'étape de collecte des données jusqu'à la phase de détermination de la périodicité de maintenance préventive optimale. Les données nécessaires à l'estimation des lois de fiabilité peuvent provenir soit d'un historique d'événements soit de mesures de dégradation réalisées lors d'inspection. Les outils mathématiques utilisés mettent en oeuvre des méthodes de régression, des méthodes de maximum de vraisemblance mais également des méthodes de Monte Carlo pour la simulation du comportement des systèmes. Chaque indicateur peut se voir affecter une incertitude liée à un niveau de confiance afin d'aider le décideur à choisir la périodicité de maintenance la plus adaptée à sa stratégie. Un cas d'étude théorique est étudié à l'aide de notre logiciel « Reliabilitix » pour illustrer la méthodologie proposée.

Research paper thumbnail of Dynamic simulation of milling operations with small diameter milling cutters: effect of material heterogeneity on the cutting force model

Research paper thumbnail of Modelisation De La Fiabilite D'Un Systeme Soumis a Des Sollicitations Variables Reliability Model for a System Subject to …

Pour évaluer la fiabilité d'un système mécanique soumis à des sollicitations variables, il est né... more Pour évaluer la fiabilité d'un système mécanique soumis à des sollicitations variables, il est nécessaire de connaître les modes de défaillance auxquels le système est soumis. Les systèmes mécaniques étant généralement complexes, cet article présente deux librairies MATLAB Reliabilitix et Simulatrix développées pour estimer la fiabilité de tels systèmes, ainsi que deux méthodes d'estimation des paramètres des lois de fiabilité : la méthode de régression et la méthode du maximum de vraisemblance (MLE). Ensuite, cet article s'intéresse à la fiabilité des systèmes soumis à la fatigue. Les deux modèles proposés se basent sur la distribution de la limite d'endurance et la loi de Wöhler. Le premier considère que les paramètres de la loi de fiabilité dépendent des sollicitations et le second est le modèle à risques proportionnels de Cox. Les deux modèles peuvent être employés pour identifier la fiabilité d'un équipement mécanique sujet à la fatigue, mais le premier est plus adapté parce qu'il dépend du mode de défaillance. Summary The estimation of reliability of mechanical systems under variable constraints needs the knowledge of the failure modes to which the system is subjected. These mechanical systems are generally complex, that is why this article presents two MATLAB libraries Reliabilitix and Simulatrix developed to estimate reliability of such systems, and two methods of reliability parameters estimation: the regression method and the maximum likelihood estimator (MLE) method. This article studies also the reliability relative to the fatigue failure mode. Two reliability models are proposed and established combining the distribution of the endurance limit and the Wöhler's law. The first one considers that the parameters of the reliability distribution depend of the operating variables and the second is Cox's proportional hazards model. Both can be used to identify the reliability of mechanical equipment subject to fatigue, but the first one is more adapted because it depends on the failure mode.

Research paper thumbnail of Reliabilitix, a Free MATLAB Toolbox for Reliability Analysis

Research paper thumbnail of Overview of reliability estimation methods for mechanical systems under operating conditions

Abstract— The estimation of reliability of mechanical sys-tems under variable constraints needs t... more Abstract— The estimation of reliability of mechanical sys-tems under variable constraints needs the knowledge of the failure modes to which the system is subjected. These me-chanical systems are generally complex, that is why this article first presents two MATLAB libraries ...

Research paper thumbnail of Modelisation De La Fiabilite D'Un Systeme Soumis a Des Sollicitations Variables Reliability Model for a System Subject to Variable Constraints

Summary The estimation of reliability of mechanical systems under variable constraints needs the ... more Summary The estimation of reliability of mechanical systems under variable constraints needs the knowledge of the failure modes to which the system is subjected. These mechanical systems are generally complex, that is why this article presents two MATLAB libraries Reliabilitix and Simulatrix developed to estimate reliability of such systems, and two methods of reliability parameters estimation: the regression method and

Research paper thumbnail of 3D projection of the LuGre friction model adapted to varying normal forces

Multibody System Dynamics

In this paper, we develop an adaptation of the LuGre friction model so as to allow the developmen... more In this paper, we develop an adaptation of the LuGre friction model so as to allow the development of the friction force and its application in any directions on systems subjected to varying normal forces. This is achieved by projecting a modified LuGre model adapted to varying normal forces in 3D along an arbitrary orthogonal system. Consequently, the direction of the friction force is automatically oriented in the correct direction, thus stick, stick-slip, and slip behavior can be represented in all directions. The projected friction model has the following friction features: stick-slip, presliding displacement, frictional lag, varying break-away force, viscous friction, Stribeck effect, and is adapted to varying normal forces. The equivalence of this projected LuGre model with the modified one is proven analytically. The friction model is then applied to simulate the friction on two mechanical systems. The first system consists of a cube sliding on a plane with a transition from ...

Research paper thumbnail of Equivalence criteria between mechanical environments

European journal of mechanical and environmental engineering, 1996

Research paper thumbnail of A Systematic Literature Review of Cutting Tool Wear Monitoring in Turning by Using Artificial Intelligence Techniques

Machines

In turning operations, the wear of cutting tools is inevitable. As workpieces produced with worn ... more In turning operations, the wear of cutting tools is inevitable. As workpieces produced with worn tools may fail to meet specifications, the machining industries focus on replacement policies that mitigate the risk of losses due to scrap. Several strategies, from empiric laws to more advanced statistical models, have been proposed in the literature. More recently, many monitoring systems based on Artificial Intelligence (AI) techniques have been developed. Due to the scope of different artificial intelligence approaches, having a holistic view of the state of the art on this subject is complex, in part due to a lack of recent comprehensive reviews. This literature review therefore presents 20 years of literature on this subject obtained following a Systematic Literature Review (SLR) methodology. This SLR aims to answer the following research question: “How is the AI used in the framework of monitoring/predicting the condition of tools in stable turning condition?” To answer this rese...

Research paper thumbnail of Experimental Measurement of Wear Indicators for Estimating the Tool Remaining Useful Life

I Remplacement optimal des outils coupants I Simulation de la dégradation des outils de coupe par... more I Remplacement optimal des outils coupants I Simulation de la dégradation des outils de coupe par un procédé gamma [3] I Utilisation et ajustement d’un modèle de Cox aux risques proportionnels pour prédire la durée de vie d’un outil coupant [1] I Vérification de la prédiction face à une nouvelle campagne expérimentale I Conception de la campagne expérimentale I Analyse de la qualité de la prédiction et de ses facteurs d’influence Context

Research paper thumbnail of Estimate of Cutting Tool Lifespan through Cox Proportional Hazards Model

IFAC-PapersOnLine, 2016

Abstract: An important proportion of the cost of machined mechanical elements emanates from the c... more Abstract: An important proportion of the cost of machined mechanical elements emanates from the cost of cutting tools inserts. A large part of these costs is due to improper maintenance decisions. In this paper, we demonstrate the use of a gamma process tool wear simulation for providing tool lifetimes at several cutting speeds. We show the use of a survival model (Cox Proportional Hazards model) on turning cutting inserts, using the cutting speed as covariate. Contrary to other approaches, the Proportional Hazards model is not used to produce the parameters of a reliability model, but the Mean Up Time is rather computed through the integration of the raw survival model reliability baseline. Additional simulated data is used to validate the model. The importance of a proper distribution of the PH model fitting data is highlighted by the experimental results.

Research paper thumbnail of Dynamic reliability degradation based models and maintenance optimization

M of industrial equipment is a lever to increase the efficiency and the productivity of industrie... more M of industrial equipment is a lever to increase the efficiency and the productivity of industries. An intelligent maintenance is achieved by determining the optimum preventive time to replace an item in order to minimize the costs and to increase the avaibility. In order to reach the optimum, one has to know the reliability and the mean residual lifetime of an item. The reliability R(t) is the probability that an item will perform a required function without failure under stated conditions for a stated period of time. This information may be obtained by three approaches that depend of the available data (figure 1)[1].

Research paper thumbnail of Singular Spectrum Analysis for Bearing Defect Detection

Journal of Vibration and Acoustics, 2011

In this work, singular spectrum analysis is employed to process vibration signals resulting from ... more In this work, singular spectrum analysis is employed to process vibration signals resulting from rolling bearings. A monitoring indicator is defined from the fact that the structure of a signal recorded from a bearing becomes more complex when the bearing becomes defective. This can be explained by the nonstationarity and the nonlinearity induced by the defect. The effects of operating parameters such as load and speed on the indicator are studied. Results demonstrate that the indicator defined in this paper is less sensitive to these parameters than the rms value, a traditional vibratory indicator.

Research paper thumbnail of Prediction of wheel wear in urban railway transport: comparison of existing models

Vehicle System Dynamics - VEH SYST DYN, 2007

One of the most important maintenance costs in tramway transport comes from wear of wheel profile... more One of the most important maintenance costs in tramway transport comes from wear of wheel profiles. In the highly competitive railway market, the prediction of wear is then a major concern of the constructors. In this article, we present and compare four models well adapted to tramway conditions, involving contacts on the rolling tread and on the flange with very different sliding and pressure conditions. Moreover, all models can be implemented from the natural outputs of the railway simulation packages classically used in industry for the dynamics design of the vehicles. The first one, proposed by Jendel, is based on the well-known Archard's wear model. Enblom continues Jendel's approach by taking into account the contribution of wheel deformation on the sliding velocity. The last two models, developed by Zobory, and Pearce and Sherratt, determine the wear from the energy dissipation in the contact area. The models are first compared on a theoretical basis and, for that p...

Research paper thumbnail of «Early Detection of Bearing Damage by Means of Decision Trees»

Journal of Automation, …, 2009

Research paper thumbnail of Analysis of the Performance of Operational Data Analysis Methods

Mechanical Systems and Signal Processing, 1996

ABSTRACT Operating data are measurements taken from a system under operating conditions. They con... more ABSTRACT Operating data are measurements taken from a system under operating conditions. They contain a combination of the system characteristics and generally unknown loading conditions. The scope of this paper is to describe several methods of investigating operational phenomena and to discuss some of their limitations. The use of transmissibilities, monophase representation of operating shapes and principle response analysis will be illustrated from results obtained from a noise-free 11 dof discrete system, or from industrial results obtained from measurements on the guiding system of a vehicle with tyres.

Research paper thumbnail of Optimain : plate-forme d'élaboration de stratégies de maintenance pour la gestion des systèmes complexes

Revue Française de Gestion Industrielle

Dans le cadre de cet article, nous présentons la plate-forme OPTIMAIN destinée à aider le gestion... more Dans le cadre de cet article, nous présentons la plate-forme OPTIMAIN destinée à aider le gestionnaire dans l'optimisation de la gestion de la maintenance de son système de production. OPTIMAIN s'oriente principalement vers l'élaboration de stratégies de maintenance de systèmes ...

Research paper thumbnail of An adaptive degradation-based maintenance model taking into account both imperfect adjustments and AGAN replacements

Quality and Reliability Engineering International

Research paper thumbnail of An adaptive opportunistic maintenance model based on railway track condition prediction

Research paper thumbnail of Comparaison des processus gamma et Wiener pour modéliser la dégradation de géométrie de voies ferroviaires

Congrès Lambda Mu 20 de Maîtrise des Risques et de Sûreté de Fonctionnement, 2016

Le but de cette communication est d'établir une comparaison des processus stochastiques gamma et ... more Le but de cette communication est d'établir une comparaison des processus stochastiques gamma et Wiener pour la modélisation de données relatives à des défauts de géométrie de sections d'une ligne ferroviaire située en Suède. Le processus gamma, de par son caractère monotone et selon la littérature, semble être utilisé de manière exclusive pour modéliser l'évolution de ce type de dégradation (Mercier et al., 2010). Toutefois l'étude de cas envisagée dans cet article comporte des évolutions de dégradation non monotones ; c'est-à-dire que le niveau de dégradation peut localement diminuer. Ce caractère non monotone peut être dû à des erreurs de mesure ou lié à des actions de maintenance mineure de nature différente (rectification du rail, remplacement des traverses, bourrage manuel du ballast). Afin de prendre en compte ce caractère non monotone, le processus de Wiener est donc également considéré. A partir des données disponibles, les deux processus sont estimés et simulés. Les deux modèles obtenus sont alors comparés sur base de l'évolution de leur espérance mathématique et de leur variance. Finalement, un modèle de durée de vie résiduelle est proposé pour ces deux processus en calculant la distribution des temps d'atteinte d'un seuil critique de dégradation de géométrie de voie. Les implications pratiques de cette étude viseront à émettre des recommandations sur le choix d'un processus stochastique pour modéliser des dégradations de géométrie de voie.

Research paper thumbnail of « Reliabilitix », un outil d'optimisation de la maintenance basé sur la fiabilité

d'une machine est primordiale. En effet, si un remplacement anticipé provoque des coûts d'interve... more d'une machine est primordiale. En effet, si un remplacement anticipé provoque des coûts d'intervention supplémentaires, l'attente de la défaillance de la machine peut avoir des conséquences bien plus importantes, non seulement par le surcoût direct et indirect des opérations de maintenance correctives, mais également par l'exposition aux risques majeurs qu'un défaut de maintenance peut entraîner. Ce dernier aspect pose le problème de la relation entre maintenance et risques, abordé dans d'autres contributions (Hadni, 2009). Dans cet article, nous nous limiterons à une optimisation de la maintenance basée sur la fiabilité, vis-à-vis de critères de coût et disponibilité. Cette approche est expliquée et illustrée depuis l'étape de collecte des données jusqu'à la phase de détermination de la périodicité de maintenance préventive optimale. Les données nécessaires à l'estimation des lois de fiabilité peuvent provenir soit d'un historique d'événements soit de mesures de dégradation réalisées lors d'inspection. Les outils mathématiques utilisés mettent en oeuvre des méthodes de régression, des méthodes de maximum de vraisemblance mais également des méthodes de Monte Carlo pour la simulation du comportement des systèmes. Chaque indicateur peut se voir affecter une incertitude liée à un niveau de confiance afin d'aider le décideur à choisir la périodicité de maintenance la plus adaptée à sa stratégie. Un cas d'étude théorique est étudié à l'aide de notre logiciel « Reliabilitix » pour illustrer la méthodologie proposée.

Research paper thumbnail of Dynamic simulation of milling operations with small diameter milling cutters: effect of material heterogeneity on the cutting force model

Research paper thumbnail of Modelisation De La Fiabilite D'Un Systeme Soumis a Des Sollicitations Variables Reliability Model for a System Subject to …

Pour évaluer la fiabilité d'un système mécanique soumis à des sollicitations variables, il est né... more Pour évaluer la fiabilité d'un système mécanique soumis à des sollicitations variables, il est nécessaire de connaître les modes de défaillance auxquels le système est soumis. Les systèmes mécaniques étant généralement complexes, cet article présente deux librairies MATLAB Reliabilitix et Simulatrix développées pour estimer la fiabilité de tels systèmes, ainsi que deux méthodes d'estimation des paramètres des lois de fiabilité : la méthode de régression et la méthode du maximum de vraisemblance (MLE). Ensuite, cet article s'intéresse à la fiabilité des systèmes soumis à la fatigue. Les deux modèles proposés se basent sur la distribution de la limite d'endurance et la loi de Wöhler. Le premier considère que les paramètres de la loi de fiabilité dépendent des sollicitations et le second est le modèle à risques proportionnels de Cox. Les deux modèles peuvent être employés pour identifier la fiabilité d'un équipement mécanique sujet à la fatigue, mais le premier est plus adapté parce qu'il dépend du mode de défaillance. Summary The estimation of reliability of mechanical systems under variable constraints needs the knowledge of the failure modes to which the system is subjected. These mechanical systems are generally complex, that is why this article presents two MATLAB libraries Reliabilitix and Simulatrix developed to estimate reliability of such systems, and two methods of reliability parameters estimation: the regression method and the maximum likelihood estimator (MLE) method. This article studies also the reliability relative to the fatigue failure mode. Two reliability models are proposed and established combining the distribution of the endurance limit and the Wöhler's law. The first one considers that the parameters of the reliability distribution depend of the operating variables and the second is Cox's proportional hazards model. Both can be used to identify the reliability of mechanical equipment subject to fatigue, but the first one is more adapted because it depends on the failure mode.

Research paper thumbnail of Reliabilitix, a Free MATLAB Toolbox for Reliability Analysis

Research paper thumbnail of Overview of reliability estimation methods for mechanical systems under operating conditions

Abstract— The estimation of reliability of mechanical sys-tems under variable constraints needs t... more Abstract— The estimation of reliability of mechanical sys-tems under variable constraints needs the knowledge of the failure modes to which the system is subjected. These me-chanical systems are generally complex, that is why this article first presents two MATLAB libraries ...

Research paper thumbnail of Modelisation De La Fiabilite D'Un Systeme Soumis a Des Sollicitations Variables Reliability Model for a System Subject to Variable Constraints

Summary The estimation of reliability of mechanical systems under variable constraints needs the ... more Summary The estimation of reliability of mechanical systems under variable constraints needs the knowledge of the failure modes to which the system is subjected. These mechanical systems are generally complex, that is why this article presents two MATLAB libraries Reliabilitix and Simulatrix developed to estimate reliability of such systems, and two methods of reliability parameters estimation: the regression method and