Dissertations / Theses on the topic 'Comportement d'usage'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 30 dissertations / theses for your research on the topic 'Comportement d'usage.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
Gomes, da Silva Alzennyr. "Analyse des données évolutives : Application aux données d'usage du Web." Paris 9, 2009. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=2009PA090047.
Nowadays, more and more organizations are becoming reliant on the Internet. The Web has become one of the most widespread platforms for information change and retrieval. The growing number of traces left behind user transactions (e. G. : customer purchases, user sessions, etc. ) automatically increases the importance of usage data analysis. Indeed, the way in which a web site is visited can change over time. These changes can be related to some temporal factors (day of the week, seasonality, periods of special offer, etc. ). By consequence, the usage models must be continuously updated in order to reflect the current behaviour of the visitors. Such a task remains difficult when the temporal dimension is ignored or simply introduced into the data description as a numeric attribute. It is precisely on this challenge that the present thesis is focused. In order to deal with the problem of acquisition of real usage data, we propose a methodology for the automatic generation of artificial usage data over which one can control the occurrence of changes and thus, analyse the efficiency of a change detection system. Guided by tracks born of some exploratory analyzes, we propose a tilted window approach for detecting and following-up changes on evolving usage data. In order measure the level of changes, this approach applies two external evaluation indices based on the clustering extension. The proposed approach also characterizes the changes undergone by the usage groups (e. G. Appearance, disappearance, fusion and split) at each timestamp. Moreover, the refereed approach is totally independent of the clustering method used and is able to manage different kinds of data other than usage data. The effectiveness of this approach is evaluated on artificial data sets of different degrees of complexity and also on real data sets from different domains (academic, tourism, e-business and marketing)
Samalin, Ludovic. "Attitudes et croyances vis-à-vis du traitement comme variables intermédiaires du comportement d'usage du médicament." Thesis, Clermont-Ferrand 1, 2016. http://www.theses.fr/2016CLF1MM21/document.
The management of patients with severe mental illnesses needs a better understanding of thefactors affecting the behaviours of clinicians and patients toward therapeutic strategies.The main objective of this thesis was to assess and identify the role of the clinician’s attitudes and patients’ attitudes toward the medication use behaviour. We conducted several studies to address this point in different mental disorders and for different type of treatment. Concerning the patients ‘attitudes toward treatment, we reported data from a study assessing the beliefs toward antipsychotics of schizophrenic patients and from a qualitative study assessing the patient’s attitudes toward the management of bipolar disorder in euthymic periods. We showed that the negative attitudes had a marked impact on the level of adherence of patients and could determine individual targets of interventions to improve them. Concerning the psychiatrists, we reported two studies assessing the clinician’s attitudes toward guidelines and long-acting injectable antipsychotics. Some specific attitudes were associated with a lower use of guidelines or long-acting formulations. These findings showed that the adherence of patient to treatment and the medical decisions of clinicians were related to their attitudes. The assessment of attitudes or beliefs in the field of mental health appears to be an essential step to promote a better comprehension of some treatment use behaviours. Our results and from other recent studies support a new paradigm for the patient adherence to treatment and the medical decision of clinicians focused on their attitudes as predicting variables
Pasquier, Hélène. "Définir l'acceptabilité sociale dans les modèles d'usage : vers l'introduction de la valeur sociale dans la prédiction du comportement d'utilisation." Phd thesis, Université Rennes 2, 2012. http://tel.archives-ouvertes.fr/tel-00840220.
Pasquier, Hélène Marie Louise. "Définir l'acceptabilité sociale dans les modèles d'usage : vers l'introduction de la valeur sociale dans la prédiction du comportement d'utilisation." Thesis, Rennes 2, 2012. http://www.theses.fr/2012REN20058/document.
The issue of this dissertation is to propose a psychosocial paradigm for the study of usage processes based on the concept of social acceptability, defined as the “value individuals attribute to objects and/or users depending on their social relationship” (Lefeuvre et al., 2008, p.101).This psychosocial paradigm finds its roots between sociological and ergonomic points of view, and is focused on the concept of social variables from acceptability models (from the HMI and MIS fields and TRA-TPB). We have established that social variables are initially neglected in usage models, nevertheless three possible evolution trajectories appear in existingmodels. This dissertation aims to enhance a usage prediction model based on the concept of social acceptability. Two hypotheses were tested. In this research, the first hypothesis states that when behaviour value is considered, social variables are a core determinant of behaviour prediction (Conner et Armitage, 1998 ; Rivis, Sheeran et Armitage, 2009 ; Manning, 2009), and the second hypothesis states that differences exist between the effects of social variables when the value of behaviour is considered. In order to empirically test these hypotheses, we operationnalized behaviour value in two ways. In studies 1 & 2, behaviour value was operationalized through behaviour valorization and tested in the transportation field. In studies 3 to 5, behaviour value was operationalized by the level of behaviour sociality and tested in the green mobility domain. Main results validate the relevance of a social acceptability oriented approach for the understanding of usage processes. Furthermore, results underline that social variables have a higher predictive power for valuable behaviours compared to less valuable behaviours
Maurel, Vincent. "Influence de l'état mécanique multiaxial induit par la découpe sur les propriétés d'usage des tôles magnétiques." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2002. http://tel.archives-ouvertes.fr/tel-00009357.
Pour résoudre ce problème dans le cas des tôles ferromagnétiques, nous avons mis en oeuvre un dispositif original alliant mesure magnétiques et sollicitations mécaniques biaxiales en traction/compression pour des tôles minces.
Ainsi, nous avons mis en évidence les faiblesses des modèles existants et rendu possible l'exploration systématique du comportement magnétique sous chargement mécaniques biaxiaux.
Bertin, Yuna. "Perception des cosmétiques et comportement d’usage : entre santé et beauté." Electronic Thesis or Diss., Université Grenoble Alpes, 2023. http://www.theses.fr/2023GRALH031.
Cosmetic make-up and skincare products are an integral part of many people’s lifes. Moreover, it can be seen as a source of well-being. Despite the considerable consumption of these products, and their social and health implications, few studies have looked into the motivations and disincentives underlying the use of make-up products. Furthermore, even fewer studies tap into the motivations and disincentives underlying the use of skincare products. Little research has been carried out assessing people's perceptions of products and the risks associated with their use. This doctoral project aims to explore this under-investigated field of research, with two objectives. Firstly, we aimed to study make-up and skincare product usage behavior, in relation to appearance and socio-cultural influence. The second aim was to identify the determinants of risk perception linked to the use of make-up and skincare products. Additionally, we aimed to study the risk perception in relation to the perception of benefits and product use, among a non-expert population. To this end, two studies were carried out among French women of legal age. In the first exploratory study, 34 semi-structured interviews were conducted and analyzed using thematic analysis. The results are consistent with the literature highlighting the role of make-up and skincare products in self-appreciation and psychological well-being, and the role of make-up in particular in managing the impressions reflected back to others and expressing an identity adapted to the social context. The use of skincare products in particular calls on themes linked to aging appearance and bodily well-being. This first study highlights the role of knowledge and trust in the perception of risks associated with the use of make-up and skincare products. Various perceived risk factors were identified, such as product composition and perceived compliance with production standards. The second study was an online questionnaire, administered to 1,274 participants. Data was analyzed using structural equation modeling. Data analysis indicates positive effects of subjective norms, general internalization of beauty standards, and motivational salience (appearance investment dimension), as well as a negative effect of self-evaluative salience (appearance investment dimension) and age, on make-up product use. The use of skincare products was positively influenced by age, anxiety about aging appearance, subjective norms, general internalization of standards and motivational salience, and negatively influenced by self-evaluative salience. In addition, the analyses revealed a negative effect of fatalistic beliefs, subjective knowledge level, and trust (in the concern of scientists and the cosmetics industry for the health of users and the environment) on the perception of risks associated with the use of make-up and skincare products. The analyses indicated a significant positive effect of trust (in the honesty of scientists and the cosmetics industry) on the perception of benefits linked to the use of make-up and skincare products, and a positive relationship between this perception of benefits and product use. Finally, this doctoral work discusses these results in relation to the literature, and presents a set of perspectives envisaged for investigating the issues of make-up and skincare product use and perception in depth
Chemak, Fraj. "Comportement des producteurs agricoles et efficacité d'usage de la ressource en eau : Cas des périmètres irrigués de la région de Sidi Bouzid en semi aride Tunisien." Montpellier 1, 2007. http://www.theses.fr/2007MON10015.
Threatened by the economic and social development, water is an increasingly rare good. More than ever concerned, Tunisia achieved a successfully water supply management policy. Today, this policy reached its limits with a mobilization rate of 87%. Hence, efforts should target to the demand management. Understanding farmer's strategies and identifying the parameters controlling production technologies are the fundamental elements to modify the consumption of irrigated sector without compromising production objectives. Ln this regard, the objective of this investigation is to analyze the performance of irrigated farms in the region of Sidi Bouzid. First, farm's survey was carried out in both public and private irrigated areas. Second, an analysis of the production system within theses farms showed an appropriate technology process. Moreover, the application of Data Envelopment Analysis (DEA) approach allowed the measurement of technica1 and allocative efficiency. Empirical findings revealed a technical inefficiency use of inputs. The average technical efficiency of water resource was onl y 68%. The comparison between both production systems revealed more important resources wasting in private farms than in public ones. Thus, the surface weIl creation strategy, as a second source of irrigation, was found to be against the sustainable use of an already overexploited ground water. However, such strategy is justified when analyzing allocative efficiency scores. Lndeed, the profitability of an activity, based on wells irrigation, appears to be much more interesting than that based on public resource. The average allocative efficiency of private farms was 73% compared to only 53% for public farms. The Horticultural cropping practice is a determinant factor of this profitability. In addition, results indicate the negative effect of land structure (area and a number of plots) and land input intensification on technical efficiency
Kerbiriou, Christian. "Impact des changements d'usage sur la viabilité d'une population menacée dans un espace multi-protégé : le Crave à bec rouge (Pyrrhocorax pyrrhocorax) sur l'île d'Ouessant." Phd thesis, Museum national d'histoire naturelle - MNHN PARIS, 2006. http://tel.archives-ouvertes.fr/tel-00177416.
L'étude s'est dans un premier temps focalisée sur l'identification des facteurs susceptibles d'influencer les paramètres démographiques de cette espèce. Le nombre de sites de reproduction apparaît comme un facteur très probablement limitant. Le succès reproducteur est quant à lui influencé par la superficie d'habitats favorables à proximité des sites de reproduction ainsi que par l'abondance des ressources alimentaires au printemps. Enfin la limitation de l'accès aux zones d'alimentation et la réduction du temps d'alimentation des oiseaux, occasionnées par la fréquentation touristique estivale du littoral, affectent la survie des jeunes Craves.
Dans un second temps, la viabilité démographique de cette population a été évaluée à l'aide de différents modèles et au travers de comparaisons de différents scénarios plausibles d'évolution et d'impacts des activités humaines. Dans l'éventualité d'une stabilisation de la fréquentation touristique et du processus d'enfrichement aux niveaux actuels, la population semble viable. Mais comparativement au contexte passé particulièrement favorable, la population semble désormais sur "le fil du rasoir", une diminution même légère d'un des paramètres démographiques conduirait à une extinction inéluctable. Compte-tenu des dynamiques actuelles, le dérangement touristique estival semble impacter le plus la population à court terme. Différents scénarios de gestion ont donc été envisagés, via notamment un modèle démographique spatialement explicite, développé au sein d'un Système Multi-Agents.
Mejri, Seifeddine. "Identification et modélisation du comportement dynamique des robots d'usinage." Thesis, Clermont-Ferrand 2, 2016. http://www.theses.fr/2016CLF22688/document.
Machining robots have major advantages over cartesian machine tools because of their flexibility, their ability to reach inaccessible areas on a complex part, and their important workspace. However, their lack of rigidity and precision is still a limit for precision tasks. The stresses generated by the cutting forces and inertia are important and cause static and dynamic deformations of the structure which result in problems of workpiece surface. The aim of the thesis work is to characterize the dynamic behavior of robots during machining operation. This work followed a three-step approach : Modeling a first model considered as a reference where the robot is at rest. Then the identification of the dynamic behavior in service. Finally, the prediction of the cutting stability using the robot dynamic model. The originality of this work is the development of new operational modal identification methods. They integrate the machining conditions and result into a more accurate model than the first model of reference without being biased by harmonics. Finally, guidlines of robot’s configurations and excitation forces’ direction are proposed to ensure the robotic machining stability
Vachon, Normand. "Étude descriptive des réactions et des comportements d'infirmières d'Info-Santé à l'égard d'usagers ayant des comportements dérangeants." Thèse, Université du Québec à Trois-Rivières, 2010. http://depot-e.uqtr.ca/1404/1/030157728.pdf.
Castagnetti, Cedric. "Amélioration du comportement cinématique des machines par l'optimisation des trajets d'usinage 5 axes." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2008. http://tel.archives-ouvertes.fr/tel-00731128.
Castagnetti, Cédric. "Amélioration du comportement cinématique des machines par l'optimisation des trajets d'usinage 5 axes." Clermont-Ferrand 2, 2008. http://www.theses.fr/2008CLF21878.
Rebergue, Guillaume. "Mesure in-situ du comportement des pièces en situation d'usinage à l'aide d'une mesure optique." Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC065/document.
Structural aluminum alloy parts used in aeronautics are manufactured in several steps, from forming processes and heat treatments to final machining. Some of the process steps induce residual stresses. The material removal during machining release these residual stresses and thus, leads to the part deformation. The in-situ measurement of these deformations becomes necessary when this phenomenon is studied. The present work address this problematic in the context of the ANR SIMP-Aero Project. It aims to define a reliable experimental technique dedicated to the measurement of part deformations during machining of large aeronautical parts. The backbone of the technique relies on Digital Image Correlation (DIC). Mainly as a consequence of the harsh constraints environment of machining, the customization of DIC is required. First, movements of the optical system are quantified and compensated for the proper measurement of the workpiece displacement. Then, the metal chips that fly between the observed surface and the acquisition system are detected and filtered by the algorithm. Finally, the developed method enables the measurement of displacement fields throughout the whole machining sequence, without interrupting it, and a measurement uncertainty of around one hundredth of a millimeter is ensured
Haddad, Madjid. "Étude de l'impact des défauts d'usinage des structures composites par détourage sur leur comportement mécanique." Toulouse 3, 2013. http://thesesups.ups-tlse.fr/2179/.
This thesis focuses on problems encountered during the trimming of composites materials using continuous fibers. The thesis is divided into three main parts. In the first part, the machinability of two composites materials made of carbon fiber and epoxy matrix at standard cutting speed and at high cutting speed is investigated. Surface damages induced are analyzed using surface roughness tester and the scanning electronic microscope. The impact of cutting conditions, machining processes (i. E. , cutting tool, abrasive diamond cutter, abrasive water jet machining), and nature of composite materials on the form and size of the surface defects are studied. The second part of the thesis concerns the study of the dust generated during trimming in terms of number of particles present in air and masses. The effect of tool geometry, composite material and cutting conditions on the generated dust is studied. The last part is dedicated to the study of the relationship between machining processes, surface defects and mechanical behaviour of composite parts in quasi-static and dynamic environment. Specimens designed for quasi static tests are instrumented on the surface for the digital images correlations and high speed cameras to monitor the damage generation and progression during the tests. The dynamic tests are instrumented by an infrared camera in order to measure the thermal dissipation during the damaging phases of specimens
Kowandy, Christelle. "Comportement tribologique de la fonte grise lamellaire 250 contre les polytétrafluoroéthylènes : Rôle des particules d'usure." Compiègne, 2007. http://www.theses.fr/2007COMP1668.
The compressors used for the blowing of the plastic bottles generally consist of a cylinder, a piston and segments which must ensure at the same time the sealing between the parts and the lubrication. The segments must be in materials known as "self-lubricating" such as polytetrafluoroethylene. However, during the contact, wear partic1es can be generated. Their morphology is an indicator of the wear process. Mechanical tests of friction were carried out with an alternate tribometer in a plane contact configuration. The materials tested were polytetrafluoroethylenes, pure or reinforced against lamellate grey cast iron. After the characterization of materials, the morphological partic1e attributes are determined by image analysis technique. Wear mechanisms are proposed and correlations between the characteristics of the wear particles, the wear rates and the tribosystem are obtained thanks to the data mining
Tash, Mahmoud. "Effect [sic] des paramètres métallurgiques sur le comportement d'usinage des alliages 356 et 319 (étude de forage et de taraudage) /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2005. http://theses.uqac.ca.
Kagnaya, Tchadja. "Contribution à l'identification des mécanismes d'usure en usinage d'un WC-6%Co par une approche tribologique et thermique." Phd thesis, École Nationale Supérieure des Mines de Paris, 2009. http://pastel.archives-ouvertes.fr/pastel-00005750.
Tahssain, Loubna. "Etude des comportements d'usage des technologies de l'information et de la communication (TIC) par les utilisateurs : une approche par le processus : cas d'un extranet dans le milieu universitaire." Aix-Marseille 3, 2008. http://www.theses.fr/2008AIX32079.
These last years have been highlighted by the rise of the power of Information and Communication Technologies (ICT) in all the fields and activities. The ICT play a crucial role to face the new logics which primarily lead to the development of the emergency concept and real-time. If the ICT produce effects as the share of information (Rice, 1984), the communication development (Reix, 1999) and the responsibility awareness of the users (Millman and Hartwick, 1987), these effects are not often systematic. Thus, a reflexion around the behaviors of the users deserves to be raised to understand the reasons behind the non continuous achievement of the objectives. ICT use is a complex concept that arise questions on the sense as well as on measurement. This implies a complexity of the vision that is completely dichotomist according to which the individuals adopt or reject technologies towards a temporary approach which they consider the use as a process likely to evolve and to change with time. Consequently, the objective of this research is to answer the following research question: What are the factors which influence the evolution of the process of the Extranet use by the users and make it possible to reach a continuous and constant use? Motivated by a will of exploring the ground of study and the technology little studied officially, this research bases its conclusions on a longitudinal case study in 6 universities in the PACA area. The discussion of the results exposes the factors which explain the under use of the technological system and recommends actions of intervention allowing a continuity of use in time
Diagne, Cheikh Guèye. "Influence des paramètres d'usinage et de chargement sur le comportement en fatigue des attaches à doigts d'ailettes de turbine à vapeur." Metz, 2000. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2000/Diagne.Cheikh.SMZ0042.pdf.
Affouard, Armelle. "Intégration du comportement cinématique des machines-outils lors du calcul de trajectoires d'usinage : résolution du problème de singularité géométrique en usinage à 5 axes." Cachan, Ecole normale supérieure, 2004. http://www.theses.fr/2004DENS0010.
Within the framework of 5 axis machining of complex surfaces, we study the influence of a tool path calculated by a CAM system on the kinematic behavior of the machine tool in High Speed Machining (HSM). HSM aims at ensuring a high displacement rate of the machine tool axes, therefore to introduce a higher continuity into the trajectory, in two ways: either by establishing a better planning of the tool's axis orientation, or by optimizing the description format of the trajectory itself. The introduction of a new description format generates a problem: the kinematic singularity for which we propose a geometrical model and a method of trajectory deformation in order to avoid it. Solving the problem pertains to a more general framework which relates to the optimization of the tool's axis orientation in the workspace in order to improve the kinematic behavior of the rotation axes of the machine tool
Belguith, Rami. "Effets du comportement de la machine et des paramètres d'usinage sur la topographie des surfaces obtenues par fraisage à grande vitesse avec des fraises à bout sphérique monoblocs." Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0127.
The optimization of the cutting parameters in high-speed machining requires the consideration of the machining errors in the modeling of the cutting forces and the surface topography. Therefore, the present study deals with the analysis of the effect of cutting parameters and machining errors on the surface topography of milled surfaces with a ball-end mill. The tool geometry was modeled taking into account all the machining errors such as runout, bending, vibrations and wear. Then, the Cutter Workpiece Engagement region 'CWE ', the cutting width and the uncut chip thickness were modeled taking into account the trace of the previous tooth. Subsequently, thermomechanical modeling of cutting forces in the milling process with a ball-end tool is made considering these errors. Finally, an analysis of the topography according to all these parameters and machining errors was carried out based on experimental validation
Thevenot, Mael. "Contact à grande vitesse en zone labyrinthe, identification des phénomènes mécaniques et thermiques et du comportement des matériaux." Thesis, Toulouse, INPT, 2020. http://www.theses.fr/2020INPT0010.
Improving the control over sealing of secondary air systems of aircraft engines require a minimum gap clearance between rotating parts and the surrounding casing, which guarantees higher engine efficiency. The tight clearance allows to reduce leakage flows but may leads to undesirable interactions between the static and rotating parts. Labyrinth seals are dynamic sealing systems for which an abradable coating is deposited on the stationary part of the seal to limit the damage of the rotating shaft. Depending on contact conditions, labyrinth-abradable interactions are potentially critical for the seal. This study aims to identify experimentally the material behaviour during these contact conditions. A high-speed contact test rig was developed to recreate contact conditions occurring in an aircraft engine. Two contact configurations involved in different locations of the engine were explored, with three thermally sprayed coatings and three honeycomb coatings, presenting different materials and surface areas. Thermomechanical characterisation is achieved with a specific instrumentation designed for the study. A tribological analysis based on the third body concept is coupled to the experimental analysis. This approach allows to identify wear mechanisms and material flows through the contact (tribological circuit), which determine the thermomechanical constraints in the high-speed contact. This work was achieved within the framework of cooperation between Safran Tech Saclay (SAFRAN group), Safran Aircraft Engines Villaroche (SAFRAN group) and the Laboratoire Génie de Production (LGP) de Tarbes
Trevisiol, Céline. "Effet de la microstructure et de la rugosité sur le comportement au frottement et à l’usure d’aciers faiblement alliés." Thesis, Compiègne, 2018. http://www.theses.fr/2018COMP2430.
This thesis is an experimental work highlighting the effects of microstructure and roughness on friction and wear behavior of low alloy steels. That's why, low alloyed steels are carrefully selected in order to generate precise microstructures. Thus, different samples characterized by a chemical composition, a microstructure and a macro-hardness are generated and characterized tribojogically by performing friction tests. An original reflection was conducted to study the tribological behavior of the same steel with different microstructures for the same level of macrohardness. In addition, the effect of normal load on the contribution of microstructure and roughness on tribological behavior is investigated. This characterization is carried out by measurements of friction coefficient, wear rate, roughness parameters, micro-hardness and nanoindentation tests, energy dispersive analyzes, observatibns by using scanning electron microscopy and analysis of wear mechanisms. Finally, 273 configurations are studied and different trends are identified, Moreover, a comparison between the results from an experimental approach and a modeling approach of the tribological behavior of dual-phase microstructures was carried out. From this study, reflections are performed as regards the modes of the applied pressure pressure between the phases as function of roughness and normal load during the experimental friction tests
Baklouti, Mouna. "Analyse tribologique du rôle de constituants dans les performances de matériaux composites organiques pour garnitures de frein." Phd thesis, Ecole Centrale de Lille, 2013. http://tel.archives-ouvertes.fr/tel-00991953.
Turki, Yosra. "Étude expérimentale des mécanismes de coupe des matériaux composites carbone-époxy : application au perçage." Amiens, 2013. http://www.theses.fr/2013AMIE0108.
The evolution of carbon/epoxy composites use in aeronautics requires a better comprehension of the machining conditions influence on these materials. Based on the experimentation, this study aims to establish the relationship between machining conditions, behavior of the machined composite and the mechanical resistance of laminates. An orthogonal cutting study shows that fibers orientation defines the mechanisms of chip formation and influences the machined surface quality and defects (size and shape). This study is then applied to drilling. The fibers orientation effect on defects location is also observed. Concerning cutting parameters, feed has more influence on the drilled hole than spindle speed. Its increase leads to the rise of drilling defects (delamination, fibers chip-out, uncut fibers…). Moreover, drill geometry has a major influence on the studied parameters. The best results are obtained with spur drill owing to the presence of two extreme points which better shear so cut carbon fibers. When drilling with a core drill bit, a chip evacuation problem and then a penetration issue has been encountered. Very high cutting forces has been recorded and a thermal degradation has been observed on surface and along the holes inside surfaces. The laminate reinforcement by Tufting (a new architecture developed in order to fill 2D composite gaps) allows a reduction of the delamination inside the hole generated by the thrust force, compared to the 2D composite. Quasi-static tensile tests show also the reinforcement benefit. The seam reduces delamination propagation and deformation of the laminate, improves its resistance to the mechanical loading and mitigates the effect of drilling defects
Nguyen-Dinh, Ngoc. "Experimental study of the trimming of carbon-epoxy composite : machinability and material integrity." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30059.
Trimming is the first operation of machining after the manufacturing and demolding of the composite structures. This operation which is usually conducted with conventional process of material removal (by cutting tool) induces various forms of damage which is accompanied by the generation of harmful particles in case of dry machining. In fact, particles generated during dry machining of composite pose a dangerous threat, as they can get suspended in the air and infiltrate inside body of operators giving rise to risk of respiratory hazard. Unfortunately, the understanding of particulate emission during machining of composite is presently incomplete. In addition, the appearance of damages located on the machined surface (due the interaction tool/plies) can reduce the structural performance in service due to the formation of stress concentration zones. As a result, it is necessary to understand the underlying causes for generation of damage, and also the relationship between machining induced damage and mechanical behavior. It is important to notice that, industrially, surface roughness criterion is widely used to quantify the machined quality of the newly generated composite surface. However, so far this has been ambiguous approach. Hence, to address the problems mentioned, this thesis focuses on three main objectives. Firstly, studies on the machinability of multi-directional specimens made of carbon fiber reinforced plastics laminates (CFRPs) during trimming with PCD (Polycrystalline Diamond) cutting tools. Specifically, the influence of cutting parameters (feed speed and cutting speed), cutting distance (tool wear) on the cutting forces, machining temperature induced as well as the multi-scale characterization of the machining induced damages have been investigated. For the multi-scale characterization of the induced machining postmortem observations of the machined specimens, using different techniques such as X-ray tomography, confocal microscopy and SEM, are used. Thanks to this multi-scale characterization, the machining quality was quantified using newly proposed parameters such as crater volume ‘CV’ based on the quantification of the crater defects and maximum depth of damage (D) based on the X-ray tomography. The second objective of this thesis was focused on influence of cutting parameters (cutting speed, feed speed, and radial depth of cut), cutting distance, and tool geometry on the number of harmful particles generated during trimming. The outcome of this study on the dust emission can be beneficial for the industrial community to select the safe machining condition for protecting the operators who potentially inhale the particles in the air in the machining area. The obtained results clearly highlighted that to reduce the emission of the harmful particles it is necessary to increase the radial depth of cut or the feed rate. However, this combination of cutting conditions, leads to poor machining quality. This inspired to propose a new design of cutting tool geometry in collaboration with ASAHI Company
Hejjaji, Akshay Amaranath. "Abrasive waterjet milling of CFRP composites and its influence on the mechanical behavior and patch adhesion intended for repair application." Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30235.
Controlled depth milling of carbon fiber reinforced plastic (CFRP) composites by abrasive water jet (AWJ) process is a recent advancement which can potentially be used for repairing composite structures. Aircraft composite structural repair is a costly affair owing to stringent requirements of skilled labor, time and regulatory certifications. Presently the aircraft maintenance industry lacks a reliable machining process for repair procedure. In comparison with conventional machining process AWJ milling could be a major advantage in the favor of the aircraft maintenance industry. However, knowledge on many aspects of this process is inadequate for reliable industrialization. Hence, this thesis focuses on narrowing this research gap by defining three objectives. Firstly, understanding the machinability of CFRPs, for this, the influence of process parameters on material removal rate, surface quality and nature and size of defects are studied. The machining quality is benchmarked using the traditional surface roughness criterion and a newly proposed criterion crater volume 'Cv' based on the quantification of the crater defects. The newly proposed machined surface quality criterion clears all the ambiguity that was previously present with the usage of surface roughness criterion. Secondly, the influence of machined surface quality and defects on static tensile and tension-tension fatigue behavior is studied for specimens with varying nature and levels of machining induced defects. The tensile strength and the endurance limits of various specimens are correlated with machining quality (Ra and Cv). The damage initiation and progression during loading and the role of defects in the promotion of the damage is studied using techniques like acoustic emission, thermography and X-ray tomography. Finally, the influence of machining quality on the quality of repair patch adhesion is examined by performing tensile tests on the specimens milled and bonded using an epoxy adhesive with new CFRP plies. These studies aid the industrial community to ascertain the usability of AWJ milling for composite repair and lay a strong foundation for industrialization of the AWJ milling process
Pateloup, Sylvain. "Modélisations et aptitudes à l'emploi des machines-outils à structure parallèle : vers une optimisation dirigée du processus." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2011. http://tel.archives-ouvertes.fr/tel-00609682.
Perrot, Camille. "Le vieillissement des groupes linguistiques au Québec." Thèse, 2017. http://hdl.handle.net/1866/20103.
Tash, Mahmoud. "Effect [sic] des paramètres métallurgiques sur le comportement d'usinage des alliages 356 et 319 (étude de forage et de taraudage)." Thèse, 2005. http://constellation.uqac.ca/580/1/24109447.pdf.