Search

International audience; This paper proposes the use of 1D basic models to build a design assistance tool capable of evaluating the heat transfer between a third-level electronic packaging and its support, considering a conventional configuration where a thermal interface material is placed between these two parts. Using this kind of tool early in the design process may facilitate choices concerning geometry and material. The packaging is modelled by a stepped beam (the equipment) and the interface layer by a nonlinear elastic foundation (the thermal interface material). Considering that the electronic equipment bends under the effect of the forces exerted by the fasteners, the tool makes it possible to determine the contact zone remaining operative after deformation, and the pressure distribution at the interface. Mechanical results are then used to calculate the steady-state heat transfer between the equipment and its support, taking into account the diffusion within the equipment and the thermal interface material, and also the thermal contact resistances, the latter being dependent on the contact pressure. A detailed case study is used to illustrate the utility of the approach. The 1D models are exploited to illustrate the interest of the design assistance tool. The influence of different parameters on the thermal performance is studied and a new innovative proposal is analyzed, which could lead to a significant increase in thermal performance.

International audience; This paper presents the experimental and numerical work achieved in the aim of evaluating the heat transfer at the interfaces of threaded spacecraft assemblies, where Thermal Interface Materials (TIMs) are placed between two surfaces to improve the thermal performance. Developing a model to predict thermal resistance for such an assembly is a serious challenge, which has to take various influencing parameters into account. First, mechanical and thermal experiments used to characterise TIMs are summarised. Second, a numerical model capable of representing the behaviour of these materials is built. To verify the mechanical model, the preload of a single fastener assembly is measured and compared with a simulation. The thermo-mechanical model is verified by an assembly heated by a power resistor to evaluate the thermal aspects. The proposed material model is able to predict the loss of preload caused by creep/relaxation of the TIM and the temperature distribution of the assembly. This work is part of a broader study that seeks to develop a multi-physics approach to evaluate the heat transfer at interfaces of space application assemblies.

International audience; This paper presents a new approach to develop digital twins of helicopter dynamic systems. Helicopter industries attach growing attention to the development of digital twins to be more predictive of mechanical parts lifetime. The number of sensors available to measure loads during flights is limited. Complementary simulations are necessary to compute all the loads that the mechanical parts undergo. A new process is described to build these simulations fed with flights data records. Complexity of helicopters dynamics systems leads to create several local models of subsystems using a multibody dynamic formalism. A study focused on a swashplate rotor assembly is presented to illustrate this approach, including a new model of bearing and its validation based on bench tests.

International audience; This paper defines a method for the optimization of design parameter tolerances. The general architecture of the proposed method is identical to that of the robust design reference method proposed by Taguchi but its content is different as the tolerances are considered as functions to be maximized here, while Taguchi\textquoterights method rather considers these tolerances as fixed data. Instead of looking for design parameters that minimize the sensitivity of some performance criteria, the design parameters are calculated so as to obtain maximal tolerance intervals, thus minimizing manufacturing costs. Performance criteria are then considered in terms of optimization constraints: each criterion gives rise to an inequality constraint that specifies the minimum level of performance that the designer wants to achieve. The possibilities offered by this method are illustrated through its use in the preliminary design of a cold-expanded bushing. In this case, tolerance optimization enables the allowable tolerances on the design diameters to be increased and performance levels are defined on the residual radial stress at the bushing/part contact radius and on the residual orthoradial (hoop) stress at the part inner radius.

International audience; This paper presents an analytical study of axial torque transfer in asplinecoupling. The model developed by Tatur has been extended in order to consider different loading cases and geometries. A demonstration of the extended model in a design process is described. Asplinecoupling is first calculated in accordance with standards. Then the extended model is used to optimize two design options: the best positions for a flange on the sleeve and for a step in the external diameter of the sleeve are determined. A finite element study has also been performed and shows that the extended model can be used to obtain excellent designs. It is also shown that the axial torque distribution mainly influences the damage related to fretting, without changing the maximum stress coefficient factor at the root of the shaft.

This research was motivated by the absence of a means to design a straight spline coupling in a reliable way. It is shown that the strain and pressure distribution in a spline coupling are not uniform. To predic t t these phenomena, an assistance tool would be of key interest. In this paper, a simplified finite element model has been made of a spline coupling to build a dimensioning tool for such couplings. This tool can give information about strain on the outside diameter of the sleeve and axial torque distribution. This study is based on an experimentally validated three-dimensional finite element model of the coupling under torsional load. Different sleeve sizes and loading methods are tested to highlight their effects on the axial torque distribution

International audience; This paper deals with a new concept of electrical power distribution system called IMPEC for Integrated Modular Power Electronics Cabinet. The paper defines methods aiming at carrying out an optimal design of IMPEC, the main variables being on one hand the number and size of power electronics module. On the other hand, reconfigurations between these modules and electrical loads are also optimized.The formalization of the problem highlights that designers must deal simultaneously with a combinatorial explosion and a multi-physical system sizing. The main objective of the study is to propose a methodological framework for solving this original optimal design problem. A heuristic-based algorithm is developed to solve this combinatorial optimization problem. A particular attention is paid to develop a weight estimation procedure using generic sizing models. Finally a mapping is performed to identify the best solutions and to highlight the technological components having the most significant sensitivity on the complete system weight.

La determination de la raideur des pieces assemblees a fait l'objet d'etudes recentes. Cependant, la plupart des modeles proposes concernent seulement des pieces de revolution avec un chargement axisymetrique. Cet article propose une demarche permettant la determination de la raideur axiale des pieces assemblees de forme prismatique et pour une position quelconque du boulon d'assemblage. Deux modeles sont proposes : le modele analytique s'appuie sur un decoupage de la piece en secteurs angulaires de rigidites differentes ; le modele "elements-finis" base sur la determination de l'energie de deformation permet de prendre en compte les differents parametres geometriques lies a la position du boulon sur la piece. Les resultats obtenus sont confrontes. Ils debouchent sur une formulation permettant le calcul de la raideur axiale equivalente de la piece prismatique et sur la determination de l'angle de basculement du plan de flexion de la tete de la vis.

The mechanical behavior of hybrid (bolted/bonded) joints applied to aeronautic structures is investigated. The joints under study are balanced single-lap joints, and an elastic behavior of the materials is assumed. A fully parametric analytical two-dimensional model, based on the finite element method, is presented. A special finite element, named "bonded beams" element, is computed to simulate the bonded adherends. The method and the equations to obtain the stiffness matrix of this new element are presented in this paper. The simulation of fasteners is examined through experimental and numerical approaches. The bolt load transfer is measured by the use of specially instrumented bolts, whereas a finite element 3-D model is developed to calibrate the analytical model. Good agreement is found between the analytical, experimental, and numerical results.

International audience; In this paper, an original approach is proposed to calculate the static load distribution and the axial stiffness of a planetary roller screw (PRS) mechanism. Assuming that the external loading is shared equally over an arbitrary number of rollers, only a sector of the system is represented to save on computing time. The approach consists in using a structure of bars, beams, and nonlinear springs to model the different components of the mechanism and their interactions. This nonlinear model describes the details of the mechanism and captures the shape of the nut as well as the bending deformation of the roller. All materials are assumed to operate in the elastic range. The load distribution and the axial stiffness are determined in three specific configurations of the system for both compressive and tensile loads. Further, the influence of the shape of the nut is studied in the case of the inverted PRS. The results obtained from this approach are also compared to those computed with a three-dimensional finite-element (3D FE) model. Finally, since the calculations appear to be very accurate, a parametric study is conducted to show the impact of the bending of the roller on the load distribution.

This paper deals with the first design phase of three-dimensional speed reducers. Concepts to help designers during the entry-level model definition are presented and, more particularly, those related to the task of geometrical synthesis. From these principles, a specific CAD tool has been built and is also described. A rough model, called a skeleton, is introduced to represent each conventional reducing stage category, thus enabling the automatic formation of entire geometrical models of speed reducers. Shaft orientations and positions are calculated from products of transformation matrices, in the same way as for spatial kinematic chain closure conventional problems. Optimisation techniques are used to obtain a preliminary dimensioning of the structure. The numerical processing is achieved progressively in three steps in order to improve the final convergence and, if necessary, to enlighten further the designer on failure origins within specification data. Three examples are given to illustrate both the creation of the geometrical model and the way results are obtained.

International audience; New methods and tools have been developed the last years to improve the understanding of gear meshing. Mechanical industries attach growing attention to the dynamic behavior of mechanical transmissions, including vibration and noise that result. The transmission error of the gear, which measures the intensity of one of the main causes of dynamic phenomena, can be considered as a relevant indicator of gear performance. This paper presents a new design method of spiral bevel gears, the objective of this method being to reduce their quasi-static transmission error. The proposed approach is based on an optimization process including loaded meshing simulations. The simulation model has been evaluated using a helicopter tail gearbox as bench test. Measurement results are given, showing a good correlation with predictions.

International audience; A simple and robust method to simulate spiral bevel gears generating and meshing processes is proposed. First, a mathematical model of universal hypoid tooth surfaces generator is formulated, based on Fong’s approach and taking into account all the kinematic motions of common CNC machine tools dedicated to hypoid gears generation. This model is general enough to allow the simulation of various hypoid gears cutting methods such as facehobbing, face-milling, plunge cutting and bevel-worm-shapedhobbing processes. In this paper, only developments related to facemilled spiral bevel gear generation are presented. It is shown that the results obtained are in good agreement with those of certified software. A simple and numerically stable algorithm is then proposed for unloaded tooth contact analysis. The simulation method is based on a discretization of one of the two conjugated tooth flank surfaces, and a specific projection of the different nodes of this discretization on the other flank. The contact path location can be easily approximated using this method. The accuracy of the location of contact is directly dependent on the mesh density. Although improving the accuracy requires an increase in computation time, this method allows obtaining in a very short time sufficiently accurate results to meet the needs of designers, particularly in the preliminary stages of design. The relative displacements of the gears can be taken into consideration. The robustness of the proposed computing process and the adjustable accuracy of the results are the two main advantages of the presented approaches.

International audience; This paper proposes several analytical approaches in a study of interference fit fasteners. The influence of both the friction factor and the interference level on the loss of axial load is investigated. The first approach exploits Lame’s equations as in previous studies while the second approach goes further by exploiting the slab method to obtain differential equations. The two approaches are evaluated and compared through a previously validated axisymmetric FE model using Abaqus.

International audience; More and more electric systems are embedded in today aircraft. As a result, the complexity of electrical power system design is increasing and the need of generic and efficient design methods is today required. Among numerous design tasks, the allocation of electric systems on the busbars of the electrical power system is considered as an important one since it has a direct impact on the aircraft mass. But due to the high number of possible allocations and regarding the large diversity of potential sizing cases for the equipments, finding the optimal allocation of electric loads is a hard task. In this paper, the problem is formalized mathematically. Then, four stochastic optimization methods are assessed on complex load allocation problems. Based on this assessment, a genetic algorithm using niching method is considered as the most appropriate algorithm for solving this aircraft design problem.

International audience; This paper aims to present the new method developed to generate optimized spiral bevel gear surfaces. Thanks to a complex non linear finite element model, the geometrical gear meshing positions under operational loads are first precisely computed. These meshing positions are then used as inputs of a calculation process that seeks to define the best tooth surface topography. So far, this activity was based on sensitivity studies conducted directly by the designer, which led to repeat calculations whose progress was difficult to control.EUROCOPTER uses now optimization algorithms to compute automatically the surfaces of the tooth contact flanks. This approach leads to higher performances of the gear while reducing the development time. This paper describes the new process implemented to design the tooth shape, and illustrates its interest through an example.

International audience; Aircraft electrical power system (EPS), in charge of supplying power to aircraft electric systems, needs a reconfiguration capability in order to overcome cases of EPS component failures. During the design phase, EPS reconfiguration elicitation is a complex task due to the high number of failure combinations and to the aeronautical operational constraints, which are to be taken into account. Therefore a knowledge-based system is developed in order to help designers for such a task. It is based on the implementation of two different types of rules: mandatory and know-how rules. EPS connectivity is managed by graph-theory algorithms. The knowledge-based system is capable of producing several reconfiguration solutions. The knowledge-based system functioning is illustrated in detail on a simplified EPS. Results on an actual and modern EPS are also presented.

International audience; Designers of aircraft electrical power system must allocate electrical systems to the electrical power system busbars. Due to the high number of possible allocations and regarding the large diversity of potential sizing situations, finding the best allocation in order to optimize the electrical power system mass is a difficult task. In this work, several stochastic combinatorial optimization methods are investigated for solving the allocation problem in the context of the more-electrical aircraft.

The load transfer in hybrid(bolted/bonded) single-lap joint is complex due to the association of two different transfer modes(discrete and continuous) through elements with different stiffness. Analytical methods exist for these two different modes, when considered separately. In this paper two one-dimensional elastic analytical models are presented for the determination of the load transfer in single lap configuration. The first one is developed by using the integration of the local equilibrium equations. From this first method an elastic-plastic approach is presented. The second one uses the Finite Element Method, introducing a new element called “bonded-bars”. These models are robust, easy to use and provide the same results. They allow us to analyze the load transfer and to evaluate different geometric and mechanical parameters’ influence. Thus they represent the first step for the design of a hybrid joint able to replace its bolted equivalent used on aircraft.

International audience; In this paper an analytical method is used to investigate the distortions of involute spline teeth. The following hypotheses are adopted: that teeth geometry is in conformity with standardisation, dimensions are nominal (no defect), there is no friction and the load is a pure torsional torque. Teeth distortions due to bending, shear, compression and foundation rotation are analysed. As the load is distributed along the tooth height, the displacement calculation differs from the conventional approach used for gear teeth. Sliding over the contact surfaces is also considered as it emerged during the study that this phenomenon, that has not hitherto been taken into account, plays a significant role. A punch model is used to describe the radial distribution of the contact pressure. Ascribing an arbitrary value to the tilted angle between the two contacting flanks enables the pressure profile to be evaluated, from which calculation of teeth distortions can be arrived at so as finally to obtain a new estimation of the tilted angle. Thus displacements and the contact load can be determined together by iterating the calculation procedure until convergence. Torsional stiffness, which is one of the main parameters required to predict the torque distribution along the spline coupling, is evaluated from the various displacement components. The results derived from the proposed analytical method are compared with finite element results and show good correlation.

The mechanical behavior of hybrid (bolted/bonded) joints is investigated. The joints under study are balanced single-lap joints, and an elastic behavior of the materials is assumed. A fully parametric analytical two-dimensional model, based on the Finite Element Method, is presented. A special Finite Element (“Bonded Beams” element) is computed in order to simulate the bonded adherends. The simulation of fasteners is examined through experimental and numerical approaches. Good agreement was found between the experimental and numerical results.

Cylindrical compression spring behavior has been described in the literature using an efficient analytical model. Conical compression spring behavior has a linear phase but can also have a nonlinear phase. The rate of the linear phase can easily be calculated but no analytical model exists to describe the nonlinear phase precisely. This nonlinear phase can only be determined by a discretizing algorithm. The present paper presents analytical continuous expressions of length as a function of load and load as a function of length for a constant pitch conical compression spring in the nonlinear phase. Whal’s basic cylindrical compression assumptions are adopted for these new models (Wahl, A. M., 1963, Mechanical Springs, Mc Graw-Hill, New York). The method leading to the analytical expression involves separating free and solid/ground coils, and integrating elementary deflections along the whole spring. The inverse process to obtain the spring load from its length is assimilated to solve a fourth order polynomial. Two analytical models are obtained. One to determine the length versus load curve and the other for the load versus length curve. Validation of the new conical spring models in comparison with experimental data is performed. The behavior law of a conical compression spring can now be analytically determined. This kind of formula is useful for designers who seek to avoid using tedious algorithms. Analytical models can mainly be useful in developing interactive assistance tools for conical spring design, especially where optimization methods are used.

During the final steps of epidermal differentiation, extracellular calcium ions enter keratinocytes and induce transglutaminase activity and comified envelope formation. In other cell types, entry of calcium mediated by ionophores has been reported to induce exocytosis of lysosomes. In this study, we investigated whether lysosomes of keratinocytes might exhibit a similar behaviour. Ionomycin treatment induced comified envelope formation in keratinocytes, but also morphological changes including plasma membrane blebbing, although no immediate alteration in cell viability could be detected. The activity of the soluble lysosomal enzymes cathepsin C and β-galactosidase in the culture medium was increased upon ionomycin treatment. Cell leakage did not seem to be responsible for this phenomenon, as suggested by measurements of the cytosolic enzymes adenylate kinase and dipeptidylpeptidase III in the culture medium. Metabolic labelling followed by immunoprecipitation showed that ionomycin induced release of cathepsin D into the culture medium. Simultaneously, lysosome-associated membrane proteins (Lamps) 1 and 2 were detected at the cell surface of ionomycin-treated keratinocytes by biochemical and morphological approaches. These results suggest that upon ionomycin treatment, calcium entry stimulates exocytosis of lysosomes in keratinocytes.

International audience; Common mechanical components can be designed manually but this involves problem simplifications. A computer can help to develop a suitable approach for optimizing design. Industrial software for spring design is comprehensive tools for validation only. To improve design assistance to the designer, this paper presents software which not only is comprehensive but also can serve as a dimensional synthesis tool for compression spring design. It exploits an optimization process for use even in the early design steps as specifications are set with interval values. It includes a large set of constraints which can express not only the designer specifications but also the standards and the technical capability limits of spring manufacturers. This process has been successfully tested by a spring manufacturer, who has used it to solve real industrial problems for 2 years. One case study is presented.

International audience; The main industrial software available to a designer during a spring definition work use exhaustive calculations from standards to make a full check of the proposed spring's compatibility with the given specifications. As far as we are aware, they don't really exploit optimisation process capabilities. This paper presents tools that exploit several optimisation techniques for custom spring design by linking both industrial and mathematical knowledge.

International audience; This paper presents two methods for selecting the best stock spring from within a database. A way of calculating the optimal custom spring design which takes into account the database properties is described and two methods that explore the neighbourhood of the optimal continuous solution are detailed. Two methods for exploring the neighbourhood of the optimal continuous solution are discussed. The first, called the "expanding" method explores the database in successive layers, and stops once a solution has been found which cannot be improved upon. The second method also uses the "expanding" technique but stops once a spring which matches the specifications has been found. The algorithm then performs a "sliding" operator, whereby the immediate neighbourhood of the existing solution is explored. When no better spring can be found, this process stops. Two examples are shown. They demonstrate the effectiveness for our approach in selecting a stock spring without exploring the whole database. The most time-consuming stage is the calculation of the optimum custom-made spring design. Both these methods are particularly useful when applied to large database.

International audience; This paper presents a calculation process to optimize the design of helical extension springs whatever the nature of the specifications. This process can be used even in the early design stages as data are set with interval values. It includes a large set of constraints, which can express the designer's requirements, but also the standards and the technical capability limits of spring manufacturers. The problem is resolved using the Excel solver. The required starting point is automatically calculated by a dedicated algorithm, which uses interval arithmetic. Two examples are presented.

International audience; This paper analyses the advantages of using a stock spring selection tool that manages the uncertainty of designer requirements. Firstly, the manual search and its main drawbacks are described. Then a computer assisted stock spring selection tool is presented which performs all necessary calculations to extract the most suitable spring from within a database. The algorithm analyses data set with interval values using both multi-criteria analysis and fuzzy logic. Two examples, comparing manual and assisted search, are presented. They show not only that the results are significantly better using the assisted search but it helps designers to detail easily and precisely their specifications and thus increase design process flexibility.

In the aeronautics field, the last decade has been marked by a constant and gradual increase of the electrification rate of the embedded systems. Today, the More Electric Aircraft (MEA) is seen as a major axis of improvement for the aviation industry to achieve increasingly ambitious objectives: reducing environmental impact, rationalisation of maintenance costs...In the more electrical aircraft concept, the electrical network plays a major role. Today engineers must imagine new architectural solutions to ensure the electricity supply while minimizing weight and cost. In this context, the PhD work consists in providing new methods to support the design of electrical network architectures. The PhD work is divided into 2 parts which can be seen as 2 separate studies which are introduced in the chapter 1.The 1st part, treated in the chapters 2 and 3, develops methods and tools to solve problems automatically for 2 architecture tasks: the definition of the network reconfiguration and the identification of the electrical load allocation on busbars. The formalization of these two issues highlights a common characteristic: the combinatorial explosion. As the consequence, methods from operational research area are selected to solve the 2 tasks in the frame of a general and consistent design process. The reconfiguration aspects are solved by a methodology coupling together: graph theory to model the network connectivity, an expert system capturing know-how rules and linear programming selecting the most efficient reconfiguration. The approach was successfully applied on existing aircraft electrical networks (A400M and A350) and on future architectures. The second task, related to the electrical load allocation, is solved using stochastic methods. The genetic algorithm using a niching method is the best assessed optimization method. It provides good and diversified load allocations to the electrical network architect. The 2nd part, treated in the chapter 4, focuses on a new technological concept the « modular and mutualised power electronics center ». This distribution system, closely linked to the more electrical aircraft, aims at sharing « m » power electronics modules to « c » electrical loads. The methods developed in this PhD aim at carrying out an optimal design of this new power center with 2 design variables: the number « m » of modules and the reconfigurations between the « m » modules and the « c » loads. Again, the formalization of the problem highlights that the designer must deal with a combinatorial explosion. The main objective of this study is to propose a methodological framework for solving this design problem. A heuristic-based algorithm is developed to solve this combinatorial optimization problem. A particular attention is paid to develop an organized weight estimation procedure using generic sizing models. Finally a mapping is performed to identify the best solutions and to highlight the technological elements having the most significant impact on the complete system weight; Dans le domaine aéronautique, la dernière décennie a été marquée par une augmentation constante et progressive du taux d’électrification des systèmes embarqués. L’avion plus électrique est aujourd’hui vu comme un axe d’amélioration majeure pour l’industrie aéronautique permettant d’atteindre des objectifs toujours plus ambitieux : réduction de l’impact environnemental, rationalisation des coûts de maintenance… Dans ce contexte, le réseau de distribution électrique joue un rôle majeur. Les architectes doivent imaginer de nouveaux concepts architecturaux afin d’assurer le « service » de fourniture d’électricité tout en minimisant la masse et le coût. Ainsi les travaux de cette thèse proposent des méthodes d’aide à la conception pour les architectes de réseau. Le manuscrit se divise en 2 parties pouvant être vues comme 2 études distinctes et qui sont introduites dans le chapitre 1.La 1ère partie, traitée dans les chapitres 2 et 3, développe des méthodes et outils afin de résoudre de manière automatique et optimale 2 tâches de l’architecte : la définition des reconfigurations du réseau et l’identification de l’allocation des charges. La formalisation de ces 2 problématiques met en lumière une caractéristique commune : l’explosion combinatoire. Ainsi les résolutions sont réalisées à l’aide de méthodes issues de la recherche opérationnelle. Un processus général est défini afin de traiter les 2 tâches de manière consistante. Les aspects liés à la reconfiguration sont traités à l’aide de : la théorie des graphes pour modéliser la connectivité du réseau, un système expert capturant les règles métiers et la programmation linéaire sélectionnant les reconfigurations les plus performantes. La méthode a été appliquée avec succès sur des réseaux avions existants (A400M et A350) ainsi que sur des réseaux plus électriques prospectifs. La deuxième tâche consistant en l’allocation des charges a été résolue à l’aide de méthodes stochastiques. L’algorithme génétique utilisant une méthode de nichage se révèle être le plus performant en proposant à l’architecte réseau des solutions performantes et variées. La 2ème partie, traitée dans le chapitre 4, s’intéresse à un nouveau concept le « cœur électronique modulaire et mutualisé ». Cet organe de distribution, étroitement lié à l’avion plus électrique, se caractérise par la mutualisation de « m » modules électronique de puissance pour « c » charges électriques. Les méthodes développées dans le chapitre 4 vise à concevoir de manière optimale ce nouveau cœur en ayant 2 degrés de liberté : le nombre « m » de modules et les reconfigurations entre les « m » modules et les « c » charges. De nouveau, la formalisation du problème met en évidence l’explosion combinatoire à laquelle est confronté le concepteur. Le principal objectif de cette étude est de proposer un cadre méthodologique pour la résolution de ce problème de conception. Ainsi une heuristique a été développée pour résoudre ce problème combinatoire. Une attention particulière a été portée pour développer des modèles de composants simples et génériques dans une procédure générale organisée. Enfin une cartographie a été réalisée afin de dégager d’une part les formes de solutions les plus performantes et d’identifier les éléments ayant les impacts les plus significatifs sur la masse du système complet.

Works of this thesis consist in a study of the spline coupling behaviour in order to develop the bases of an assistance tool to the conception. We use tridimentionnal Finite Elements models validated by experimental studies. Calculus methods, which are fast and accurate, are so defined. In a first part, we examine the limits of the dimension normalization and the necessity to analyze the spline coupling behaviour in the radial and axial directions. The radial behaviour study is based on a method, which defines on the one hand a pressure repartition model, called “punch model” and on the other hand the teeth rigidity. This last parameter is used after to describe the axial behaviour of the spline. An analyse of couple transfert along the spline enables to study the geometry influence of shaft and sleeve and the load. Finally we have worked on an extension of analytical method of the axial behaviour to widen the application domain in the case where the teeth reach beyond the contact. We have identified the possibility to use an equivalent global rigidity, variable along the contact, and able to take into account some parasite phenomena.; Les travaux de cette thèse consistent à étudier le comportement des cannelures afin de développer les bases d'un outil d'aide à la conception. Nous nous appuyons sur une modélisation Eléments Finis tridimensionnels validée par des études expérimentales. Des méthodes de calcul rapides et précises sont ainsi définies. Dans la première partie nous mettons en évidence les limites des normes de dimensionnement et la nécessité d'analyser le comportement d'une cannelure suivant les directions radiale et axiale. L'étude du comportement radial est basée sur une méthode déterminant d'une part un modèle de répartition de pression dit de « punch » et d'autre part la rigidité des dents. Ce dernier paramètre est utilisé ensuite pour décrire le comportement axial de la cannelure. Une analyse du transfert du couple le long de la cannelure a permis d'étudier les influences de la géométrie des pièces et du chargement. Enfin, nous avons travaillé à l'extension du modèle analytique relatif au comportement axial en vue d'élargir son domaine d'application aux cas où les dentures débordent de part et d'autre du contact. Nous avons identifié la possibilité d'utiliser une raideur globale équivalente, variable le long du contact, et capable de rendre compte d'un certain nombre de phénomènes parasites.

Works of this thesis consist in a study of the spline coupling behaviour in order to develop the bases of an assistance tool to the conception. We use tridimentionnal Finite Elements models validated by experimental studies. Calculus methods, which are fast and accurate, are so defined. In a first part, we examine the limits of the dimension normalization and the necessity to analyze the spline coupling behaviour in the radial and axial directions. The radial behaviour study is based on a method, which defines on the one hand a pressure repartition model, called “punch model” and on the other hand the teeth rigidity. This last parameter is used after to describe the axial behaviour of the spline. An analyse of couple transfert along the spline enables to study the geometry influence of shaft and sleeve and the load. Finally we have worked on an extension of analytical method of the axial behaviour to widen the application domain in the case where the teeth reach beyond the contact. We have identified the possibility to use an equivalent global rigidity, variable along the contact, and able to take into account some parasite phenomena.; Les travaux de cette thèse consistent à étudier le comportement des cannelures afin de développer les bases d'un outil d'aide à la conception. Nous nous appuyons sur une modélisation Eléments Finis tridimensionnels validée par des études expérimentales. Des méthodes de calcul rapides et précises sont ainsi définies. Dans la première partie nous mettons en évidence les limites des normes de dimensionnement et la nécessité d'analyser le comportement d'une cannelure suivant les directions radiale et axiale. L'étude du comportement radial est basée sur une méthode déterminant d'une part un modèle de répartition de pression dit de « punch » et d'autre part la rigidité des dents. Ce dernier paramètre est utilisé ensuite pour décrire le comportement axial de la cannelure. Une analyse du transfert du couple le long de la cannelure a permis d'étudier les influences de la géométrie des pièces et du chargement. Enfin, nous avons travaillé à l'extension du modèle analytique relatif au comportement axial en vue d'élargir son domaine d'application aux cas où les dentures débordent de part et d'autre du contact. Nous avons identifié la possibilité d'utiliser une raideur globale équivalente, variable le long du contact, et capable de rendre compte d'un certain nombre de phénomènes parasites.

A joint is called as a hybrid joint when it associates two different joining technologies. This study deals with the combination of bolting and bonding. The longitudinal joints of fuselage of civil aircraft in the single-lap configuration are looking as the application case of this study. Parametrical tools in the shape of computer codes are developed and provide the distribution of the load transfers in the adherends and the fasteners as well as the distribution of the adhesive stress, as a function of the mechanical and geometrical parameters of the joint. These tools are based on the development of 1D and 2D analytical models, which assume an isotropic elastic behaviour of materials, and which are grounded on the creation of new finite elements which are formulated in order to simulate both bonded adherends. A 3D numerical model (FEM) is developed in order to access to the local mechanical behaviours, and the use of which is interesting in the determination of the fasteners stiffnesses, used in the analytical approaches. The experimental measurement of bolt load transfers under low applied loads thanks to instrumented bolts validates and calibrates the analytical and numerical approaches, whereas the fatigue tests estimate the gains in fatigue life.; Un assemblage est dit hybride quand il associe deux techniques d'assemblage différentes. La présente étude s'intéresse à la combinaison du collage et du boulonnage. Les jonctions longitudinales de fuselage d'avions civils, montées en simple cisaillement, constituent un cas d'application des travaux. Des outils paramétriques sous la forme de programmes informatiques sont mis au point et donnent la répartition des transferts de charge dans les substrats et dans les fixations ainsi que la répartition des contraintes adhésives, en fonction des paramètres géométriques et mécaniques de l'assemblage. Ces outils reposent sur le développement de modélisations analytiques 1D et 2D, qui supposent un comportement élastique et isotrope des matériaux, et qui sont basées sur la création de nouveaux éléments finis formulés pour simuler deux substrats collés. Un modèle 3D EF est développé afin d'accéder aux comportements mécaniques locaux, et dont l'utilisation est intéressante dans la détermination des raideurs des fixations utilisées dans les modélisations analytiques. La mesure expérimentale du taux de transfert aux fixations sous faibles charges à l'aide de boulons instrumentés valide et calibre les approches analytiques et numériques, tandis que les essais en fatigue estiment les gains en durée de vie.

A joint is called as a hybrid joint when it associates two different joining technologies. This study deals with the combination of bolting and bonding. The longitudinal joints of fuselage of civil aircraft in the single-lap configuration are looking as the application case of this study. Parametrical tools in the shape of computer codes are developed and provide the distribution of the load transfers in the adherends and the fasteners as well as the distribution of the adhesive stress, as a function of the mechanical and geometrical parameters of the joint. These tools are based on the development of 1D and 2D analytical models, which assume an isotropic elastic behaviour of materials, and which are grounded on the creation of new finite elements which are formulated in order to simulate both bonded adherends. A 3D numerical model (FEM) is developed in order to access to the local mechanical behaviours, and the use of which is interesting in the determination of the fasteners stiffnesses, used in the analytical approaches. The experimental measurement of bolt load transfers under low applied loads thanks to instrumented bolts validates and calibrates the analytical and numerical approaches, whereas the fatigue tests estimate the gains in fatigue life.; Un assemblage est dit hybride quand il associe deux techniques d'assemblage différentes. La présente étude s'intéresse à la combinaison du collage et du boulonnage. Les jonctions longitudinales de fuselage d'avions civils, montées en simple cisaillement, constituent un cas d'application des travaux. Des outils paramétriques sous la forme de programmes informatiques sont mis au point et donnent la répartition des transferts de charge dans les substrats et dans les fixations ainsi que la répartition des contraintes adhésives, en fonction des paramètres géométriques et mécaniques de l'assemblage. Ces outils reposent sur le développement de modélisations analytiques 1D et 2D, qui supposent un comportement élastique et isotrope des matériaux, et qui sont basées sur la création de nouveaux éléments finis formulés pour simuler deux substrats collés. Un modèle 3D EF est développé afin d'accéder aux comportements mécaniques locaux, et dont l'utilisation est intéressante dans la détermination des raideurs des fixations utilisées dans les modélisations analytiques. La mesure expérimentale du taux de transfert aux fixations sous faibles charges à l'aide de boulons instrumentés valide et calibre les approches analytiques et numériques, tandis que les essais en fatigue estiment les gains en durée de vie.