Dissertations / Theses on the topic 'Assemblages collés – Essais dynamiques'
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Tahan, Gilles. "Étude des assemblages collés sous choc - Propriétés mécaniques après choc laser." Thesis, Brest, École nationale supérieure de techniques avancées Bretagne, 2018. http://www.theses.fr/2018ENTA0014.
Full textThe study presented follows on from the work carried out during different projects in different laboratories concerning the development of a laser shock adhesion test. The goal is to develop a method for evaluating the mechanical properties after laser impact of a bonded assembly. It will therefore not be a question of evaluating a level of adhesion using laser shock, but of considering and evaluating the possible influence of a laser shock on the mechanical properties of an assembly. This study therefore only concerns healthy assemblies, the mechanical properties of which should be evaluated before and after impact, for different amplitudes in the usual pressure range of the LASAT method (LASer Adhesion Test). This characterization of assemblies involves the choice of a method suitable for adhesive joints, capable of taking into account the specificities linked to the geometry of the substrate, but also of generating a desired stress field. The method adopted is the ARCAN mechanical test, capable of evaluating the resistance of a bonded assembly under quasi-static stresses, in tension, in shear or mixed. In addition, the ARCAN test allows the identification of behavioral laws of adhesive joints. Likewise, it is possible to characterize the composite lamellae in their out-of-plane behavior. This work was carried out at Institut de Recherche Dupuy de Lôme (IRDL), on ENSTA Bretagne site (Brest), in partnership with Engie Ineo whose activity, the construction of radomes in composite materials, is concerned with questions of control of bonded assemblies. This work was also the occasion of a collaboration with the CEA DAM DIF which made available ESTHER laser - material interaction simulation code
Ziane, Elbekkaye. "Approche mécanique et physicochimique du comportement des assemblages collés : application aux tôles d'acier galvanisées." Compiègne, 1986. http://www.theses.fr/1986COMPE057.
Full textKhammassi, Sabrine. "Nanotechnology and bonded joints : an investigation of the mechanical performance of an adhesive doped with nanofillers." Electronic Thesis or Diss., Brest, École nationale supérieure de techniques avancées Bretagne, 2021. http://www.theses.fr/2021ENTA0021.
Full textAdhesively bonded joint is a joining technique that is increasingly in a request today in many fields such as the automotive, aerospace, and naval. The adhesive selection is an important parameter to guarantee the reliability and durability of an adhesively bonded joint. It is well known that the wrong design of a bonded joint, the wrong choice of adhesive, or even a poorly executed surface treatment can have dramatic consequences. In terms of performance, the incorporation of carbon-based nanoparticles into the adhesive improves the performance of bonded joints. In this study, DGEBA adhesive doped by three kinds of nanofillers is established. Indeed, the adhesive has been doped with carbon nanotubes (CNT), graphene nanoplatelets (GNP), and carbon black (CB) with different mass fractions (1wt.%, 2wt.%, and 5wt.%). The overall objective is to study the influence of the type, mass fraction, and dimensions of the nanofillers on the mechanical behavior of the adhesive and the bonded joint. The results showed that each type of adhesive reinforced with nanofillers has a good potential in terms of mechanical behavior under static and dynamic loadings. However, the presence of a high mass fraction of nanoparticles tends to lead to degradation compared to the neat adhesive due to the transformation in microstructure morphology and physicochemical interactions. In addition, to quantify the damage resistance of the nanofiller-doped adhesive and demonstrate the adhesion compatibility with various kinds of substrates; DCB and ENF tests were performed on aluminum/aluminum and composite/composite bonded joints. Besides, numerical models taking into account the damage of the doped adhesive were developed and validated with the experimental results. This study demonstrates that the type, mass fraction, size, and shape of nanofillers play an important role in improving the performance of the adhesively bonded joints
Ecault, Romain. "Etude expérimentale et numérique du comportement dynamique de composites aéronautiques sous choc laser. Optimisation du test d'adhérence par ondes de choc sur les assemblages composites collés." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2013. http://www.theses.fr/2013ESMA0031/document.
Full textThis work aims the development of a non-destructive technique to control the mechanical quality ofaeronautics adhesive bonds (ENCOMB project). Shocks were realized by use of laser sources or gas gun, anddifferent techniques were used to analyse the shocks such as: VISAR, PDV, Shadowgraphy, optical andconfocal microscopy, X-ray radiography, ultrasound testing…Epoxy resins and carbon/epoxy compositelaminates were first investigated. Monitored laser shocks, in addition to post-mortem analyses, enabled tobetter understand the shock phenomenon on these complex materials. The results obtained on bondedcomposite showed that the laser shock technique can be used to discriminate different adherence levels.The use of numerical models, developed thanks to the experimental data, enabled to analyze the shockpropagation in these complex assemblies. They also evidenced the need for optimization, in order to testonly the bond interface and not to break the composite parts on the assembly. Several optimizationsolutions are formulated such as the use of tuneable pulse duration, or double shock configurations. Someof these solutions have been experimentally validated, and the numerical optimization gives the shockparameters to use for the next experimental campaigns. Finally, this work provides original results on thedynamic behaviour of composite materials under laser shock and leads to the adaptation of the laser shockadhesion test to any kind of bonded composite assemblies
Batisse, Dominique. "Rupture sous sollicitations dynamiques d'assemblage collés." Mulhouse, 1995. http://www.theses.fr/1995MULH0449.
Full textBen, Salem Naoufel. "Fiabilité des assemblages structuraux collés pour applications spatiales." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14681/document.
Full textAdhesive bonding is being strongly considered in space applications CNES as anadvantageous assembly technique for future launchers. Correct design of adhesive joints is of majorconcern. Aerospace adhesives are tough viscoelastic matrices (special epoxy resins) reinforced withnano-, or microparticles. Extended use of adhesive joints in structural applications is limited due to thedifficulties in predicting in-service performance, frequently leading to over-conservative design.Three structural adhesives (Hysol®EA 9321, Hysol®EA 9394 and Hysol®EA 9395) wereselected. After their bulk characterization, statistical studies to highlight effects of different parameterse.g. speed, test piece geometry, degree of polymerization were undertaken.In the second stage, fracture mechanics tests were effected employing: the double cantileverbeam (DCB) configuration (mode I characterisation), the three point bending end-notched flexure(ENF) (mode II) and the mixed-mode bending (MMB) (combined mode I/II loading). Crack growth inbonded joints was investigated in a novel way. To refine standard test protocol, the backface strainmonitoring technique was used. Strain gauges were used to measure the strain on the exposed skin ofthe adherends during crack onset and propagation. This method allows better estimation of the crackfront position as well as fine investigation of the stress distribution along the bondline and in the crackfront vicinity. Digital image correlation (DIC) was also used to compare analytical models, e.g.Timoshenko beam on elastic foundation model with experimental results
Nguyen, Thi-Hoa-Tam. "Modèle d’endommagement des assemblages collés : identification et application à la description d’un essai de vieillissement accéléré." Paris Est, 2008. http://pastel.paristech.org/5199/01/manuscrit_final_NGUYEN.pdf.
Full textCouchaux, Maël. "Comportement des assemblages par brides circulaires boulonnées." Rennes, INSA, 2010. http://www.theses.fr/2010ISAR0030.
Full textThis thesis deals with the elastic and elasto-plastic behaviour of bolted circular flange joints used in steel structures. The aim of the work is to provide practical design methods for determining the static resistance of such flange joints as well as the stress concentration factors for the parts which are fatigue sensitive which are the tube wall at the weld toe and the bolts. In order to be able to cover the range of joint sizes that one finds in construction, three joint configurations were studied: L stubs under an axial load in the stem, flange joints with an axial applied to the connected tube and flange joints submitted to bending moments. The experimental, numerical and theoretical studies carried out on the three joint configurations are the subjects of chapters II, III and IV of the thesis. In chapter I the phenomena of surface contact between the adjacent flanges is clarified by a specially developed beam model whose validity is supported by the results from a finite element model including contact elements. To begin with a programme of tests was carried out for each of the joint configurations so as to obtain knowledge of their elastic and elasto-plastic behaviours and the results obtained are presented and discussed. Particular attention was paid to the study of the influence of bolt preloading and of out-of-plane imperfections of the flange surfaces on the elastic behaviour, in particular in relation to the tube wall stresses ranges at the weld toe and to the loading in the bolts which is essential information required for determining the fatigue life of those components. Since each specimen was loaded to failure, an experimental evaluation of the joint’s static resistance finally obtained. Using the ANSYS code, finite element models with brick elements and contact elements were developed for each of the joints configurations. The results from the finite element analyses were compared favourably with the test results both from the present testing but also from available published work. Thus validated, the finite element models were used to carry out parametric studies with the purpose of not only supplementing the experimental results but also to bring more light on certain aspects of the joint behaviour which could not be examined in sufficient detail during the test programme, such as the evolution of the contact zone with loading. Theoretical models were developed to describe the joint configuration behaviour in the elastic range, both for providing the stress concentration factors for the fatigue sensitive components and for estimating the joint stiffness. In order to determine the static resistances of flange joints, under axial load or under moment, theoretical limit state models are derived. The predictions of the joint behaviour and resistance models provide satisfactory results when compared to results both experimental and by finite element analyses. In all of the latter models the influence of contact is taken into account. Finally, based on the latter theoretical models, practical methods for determining design values of resistances of flange joints, under axial load, moment or a combination of moment and axial load, are proposed
Hervé, Catherine. "Étude des critères et des procédures pour le contrôle et la qualification de tubes en matériaux composites et assemblages collés." Compiègne, 1989. http://www.theses.fr/1990COMPD222.
Full textFuseau, Christelle. "Caractérisation thermomécanique des assemblages mixtes métal/composite et métal/polymère." Poitiers, 1998. http://www.theses.fr/1998POIT2329.
Full textGay, Elise. "Comportement de composites sous choc induit par laser : développement de l'essai d'adhérence par choc des assemblages de composites collés." Phd thesis, Ecole nationale supérieure d'arts et métiers - ENSAM, 2011. http://tel.archives-ouvertes.fr/tel-00667560.
Full textTchalla, Tatiana Siwavi. "Durabilité d'assemblages métal/élastomère en milieu marin." Thesis, Brest, 2017. http://www.theses.fr/2017BRES0121/document.
Full textIn some industrial applications, bonding rubber coatings to metallic pipelines is a suitable solution to protect them from marine corrosion. This study deals with the long term behavior of such metallic coated pipelines in a marine environment. Two different approaches have been developed. The first focuses on degradation data of pipelines used for around thirty years in normal service conditions. As these bonded assemblies are different in terms of material formulations, manufacturing processes and aging conditions, statistical tools were used to identify homogeneous groups with identical aging mechanisms. Also, based on these results, the main degradation mechanisms of the rubber coating were established. The second approach focused on pipelines used currently in renovation operations. An experimental methodology was developed in the laboratory to accelerate aging processes. The bulk materials, surfaces and interfaces were characterized physically, chemically and mechanically before and after natural sea water ageing. This enabled an understanding of the mechanisms and kinetics governing adhesion and degradation to be developed. It also allowed the influence of sea water aging on the failure strength of the assembly of interest to be investigated
Langrand, Bertrand. "Ruine des structures aéronautiques rivetées aux chargements de type explosion ou pression dynamique." Habilitation à diriger des recherches, Université de Valenciennes et du Hainaut-Cambresis, 2010. http://tel.archives-ouvertes.fr/tel-00568194.
Full textDestouesse, Villa Jaime. "Caractérisation et modélisation des joints de colles sous sollicitations bi-axiales statiques." Thesis, Brest, École nationale supérieure de techniques avancées Bretagne, 2018. http://www.theses.fr/2018ENTA0008/document.
Full textToday, structural bonding presents an interesting alternative to conventional methods of assembly, in order to reduce the weight within aeronautical structures. However, the use of this method raises many questions in terms of design, characterization or modeling. This work presents a robust experimental work, aiming two main objectives: (i) select the most suitable instrumentation for the characterization of the behavior of bonded joints up to failure and (ii) predict the behavior of bonded joints from complete characterization and modeling under quasi-static bi-axial loading, using a simple test, directly integrated to industry. In a first stage, to achieve this goal, modified Scarf test has been proposed to characterize the mechanical behavior of adhesive joints. This type of specimen allows applying multiaxial loadings without having high-stress concentrations near the edges. The second part of the thesis deals with the development of a strategy for simplifying the characterization of a bonded joint using some hypotheses (stress/strain states). This strategy allows obtaining the intrinsic behavior of the adhesive in the form of the stress/strain curves. The last part of this work deals with the identification and selection of the most appropriate instrumentation systems in the experimental characterization
Lahouar, Mohamed Amine. "Tenue au feu des goujons collés dans le bois et dans le béton." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1027/document.
Full textPost-installation of rebars is a structural joining technique allowing the connection and the load transfer between two neighboring structural elements using steel rebars and adhesive polymers. Post-installed rebars were initially used in concrete constructions in retrofitting, extension and in repairing structures by adding new concrete sections to existing elements. Over the time, the improvement in mechanical and adhesion properties of polymer adhesives have allowed to enhance the mechanical behavior of post-installed rebars and led to achieve equivalent or even higher mechanical responses than cast-in place rebars at normal operating temperatures. Thus, post-installed rebars have gradually replaced cast-in place rebars in new constructions for some applications by offering advantageous solutions and flexibility allowing meeting the high architectural requirements. However, the mechanical behavior of post-installed rebars is essentially governed by the mechanical properties of polymer resins, which remain highly sensitive to temperature variation. Consequently, the temperature increase of the post-installed rebars presents a potential risk affecting their safety use. Therefore, fire presents a serious hazard that should be considered when designing post-installed rebars. Recently, the technique of post-installed rebars, exclusively used in reinforced concrete structures, has been transferred to wood structures construction, and called "glued-in rods". This technique, initially used in the retrofitting and the reinforcement of historical monuments, is today used in new construction thanks to its good mechanical and seismic behavior in addition to the possibility it offers to make invisible connections. However, glued-in rods face the same problems as post-installed rebars, especially concerning the temperature increase. The aim of this thesis is to study the evolution of the mechanical behavior of these two connection techniques in order to suggest a design method allowing ensuring their safe use in a fire situation. The study is divided into four levels:i- Study of the behavior of chemical anchors at the scale of materials through characterization tests performed on the anchor components, with a particular emphasis on the study of phenomena occurring at high temperature in the polymer resin.ii- Study of the global behavior of chemical anchors by means of pull-out tests performed at high temperature, at constant load and at stabilized temperature, carried out on post-installed rebars in concrete cylinders and on glued-in rods in parallelepipeds of spruce glulam.iii- Study of the mechanical behavior at high temperature of chemical anchors at the scale of the structure through a full-scale fire test carried out on a cantilever concrete slab connected to a concrete wall using eight post-installed rebars. Test results were also used to validate the suggested design method to predict the fire resistance duration of post-installed rebars in a fire situation.iv- Theoretical study on the evolution of the stress distribution along the anchor during a temperature variation, through the development of a non-linear shear-lag model, allowing to obtain the theoretical stress profiles for any thermal distribution, from the experimental input data obtained by pull-out tests
Siryabe, Emmanuel. "Evaluation non destructive par ultrasons de l'adhésion aux interfaces de joints collés." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0427/document.
Full textThe aim of this thesis is to develop NDT ultrasonic methods for the evaluation of the adhesion at interfaces in bonded joints.To address this problem, the assemblies are made of aluminum substrates (isotropic, elastic) and epoxy adhesive (isotropic,viscoelastic). Depending on the geometry of the studied assemblies, two methods are proposed to obtain quantitativeinformation on the adhesion level. The first method is suitable for three-layered plate-like samples. It consists in analyzingthe transmission of bulk ultrasonic plane waves through the assembly immersed in water. The consequences of a inapropriatesurface treatment of the substrates on the measurement of viscoelastic moduli of the joint are studied. It has been shown thatdegraded interphases cause an apparent anisotropy of the measured elastic moduli of the joint. This anisotropy was quantifiedusing two parameters β1 and β2 whose values can reveal the quality of the interphases. Then, the elastic moduli (or stiffnesseskL and kT) of the interphases were estimated, assuming that the adhesive layer properties are known. It was shown that theirvalues are higher when the adhesion is nominal, and are strongly decreased when the adhesion is degraded. Measurements ofthe mechanical strength, on samples prepared under the same conditions, confirmed the drops in these elastic moduli. Thesecond method is more suitable for lap joint samples. It is based on the Lamb wave transmission coefficient measured fromone substrate to the other, across the overlap zone. A numerical sensitivity analysis (finite element model) of the transmissioncoefficients of Lamb waves showed that the mechanical properties of the interphases (modeled by interfacial stiffnesses) canbe evaluated if the other characteristics of the assembly are well known. Experimental measurements of the transmissioncoefficients were then performed on two samples. One of them has interphases with nominal adhesion and the other hasdegraded interphases. A comparison between the measured results obtained for the different modes and numericalsimulations was used to determine the values of the interfacial stiffnesses for each sample. Again, it was observed that pooradhesion leads to low values of the interfacial stiffnesses of the interphases, that can be quantified using guided ultrasonicwaves
Mejri, Mohamed. "Étude mécano-fiabiliste des structures collées pour applications marines." Brest, 2008. http://www.theses.fr/2008BRES2056.
Full textVerdret, Yassine. "Analyse du comportement parasismique des murs à ossature bois : approches expérimentales et méthodes basées sur la performance sismique." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0010/document.
Full textThis thesis presents a study of the seismic behavior of light timber frame walls with stapled and nailed sheathings through experimental approaches and the development of a methodology for the application of seismic performance-based methods. The experimental approaches consist of three test campaigns: (1) a series of static tests on stapled and nailed connections, (2) a series of static tests performed on light timber frame walls and (3) a series of dynamic tests performed on light timber frame walls on a vibrating table. The database consists of these test results then allows the examination of strength and stiffness properties of the wall elements according to the stress conditions (strain rate, vertical load). The development of a macro-scale modeling of the cyclic and dynamic behavior of such elements is also proposed using constitutive law models. A framework of the application to light timber frame structures of seismic performance-based methods based (N2 method and MPA method) and a vulnerability analysis - fragility curves - using the N2 method are proposed
Joannès, Sébastien. "Caractérisation mécanique et outil d'aide au dimensionnement des collages structuraux." Phd thesis, École Nationale Supérieure des Mines de Paris, 2007. http://tel.archives-ouvertes.fr/tel-00288527.
Full textFestjens, Hugo. "Contribution à la caractérisation et à la modélisation du comportement dynamique des structures assemblées." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2014. http://www.theses.fr/2014ECAP0028/document.
Full textAt first sight, riveted and bolted connections seem to be one of the simplest mechanical systems possible. The primary function of these elements is to provide a rigid clamping between the components they assemble. The designing of these parts to nominal static stresses is already quite mastered. However, engineers are still bothered when it comes to modeling these components which have been studied for more than 50 years. This paradox can be explained by the large damping ratios joints generate in structures. The vibration level of a system is directly related to its damping ratio, i.e. its ability to dissipate or store energy. In the field of transport, among others, vibrations are unwanted because they affect the comfort of the users or the integrity of structures. A good designing of jointed structures is likely to improve the vibration behavior of mechanical systems. Nowadays, numerical calculations allow for the computing of the modes but the damping is still measured, a posteriori, through expensive tests. This is explained by the multi-scale nature and the complexity of contact physics. That is why the dynamic behavior of assembled structures remains an area of study for researchers. The work of this thesis aims to provide practical solutions for the identification and the designing of reduced order models for the dynamics of assembled structures
Zabbal, Paul. "Conception d’un dispositif de contrôle non-destructif par ultrasons de structure collée exploitant une cavité réverbérante à retournement temporel." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0316/document.
Full textBonding is of great interest to replace traditional assembly techniques, as it makes it possible to lighten structures, through a better distribution of stresses but also to limit the stresses associated with assembling different materials. However, the lack of a robust non-destructive control technique for bonding quality and more particularly adhesion slows down its development, particularly in the aeronautical field. In this work an ultrasonic inspection method of glued interfaces which should reveal defects in adhesion is proposed. This technique is validated on a system representative of industrial applications, metal substrates bonded by a thin film epoxy adhesive. Defects have been introduced into the adhesive interface (in the adhesive or at the adhesive/substrate interface) in order to simulate defects encountered in an industrial environment. In order to improve the detection capabilities of conventional linear ultrasonic guided waves methods, algorithms for reconstructing optimized dispersion curves have been developed. However, the guided waves were not sufficiently sensitive to low interfaces in this configuration, where adhesives are thin, and an uncertainty of material thickness is tolerated. Therefore, control methods based on the non-linear interaction between a high amplitude ultrasonic wave and a defect are proposed. To detect and quantify these non-linearities, sufficiently energetic ultrasound must be generated, which generally involves the use of potentially intrinsically non-linear electronic power devices. To overcome these technological limitations, a dedicated device is proposed, using transducers powered under low voltage and placed on a reverberant object. The emission of complex signals previously established by calibration makes it possible to concentrate acoustic energy temporally and spatially, to generate after time reversal ultrasonic particle movements of high amplitude on the surface of the controlled sample. To validate this approach, the device is used to control glued interfaces in which different types of gluing defects have been introduced: pollution (PTFE particles, release agent, fingerprints, etc.), insert. The samples are finally mechanically tested to assess the sensitivity of the interface resistance to the presence of these defects
Meaud, Charlotte. "Analyse multi-échelle des connexions par collage : application aux éléments structuraux multimatériaux fléchis." Phd thesis, Université Claude Bernard - Lyon I, 2012. http://tel.archives-ouvertes.fr/tel-00977408.
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