Дисертації з теми "Delamination of Composites"
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Alessa, Hassan Ali. "Delamination in Hybrid Carbon/Glass Fiber Composites." University of Dayton / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1399037290.
Повний текст джерелаCanturri, Gispert Carla. "On delamination directionality and migration in laminated composites." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/18169.
Повний текст джерелаLee, Jaehong. "Vibration, buckling and postbuckling of laminated composites with delaminations." Diss., This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-06062008-170322/.
Повний текст джерелаMalik, Basharat U. "Fatigue delamination growth under cyclic compression in unidirectional composites." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/12094.
Повний текст джерелаXu, Ying. "Detection of delamination in composites with fiber optic sensor /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202004%20XU.
Повний текст джерелаIncludes bibliographical references (leaves 194-209). Also available in electronic version. Access restricted to campus users.
Daniewicz, David Joseph 1965. "Edge delamination in advanced laminated composites, theory and verification." Thesis, The University of Arizona, 1990. http://hdl.handle.net/10150/277294.
Повний текст джерелаJavidrad, Farhad. "The development of a finite element for delamination growth in composites." Thesis, Imperial College London, 1995. http://hdl.handle.net/10044/1/7731.
Повний текст джерелаGambone, Livio R. "The effect of R-ratio on the mode II fatigue delamination growth of unidirectional carbon/epoxy composites." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/29968.
Повний текст джерелаApplied Science, Faculty of
Materials Engineering, Department of
Graduate
Gozluklu, Burak. "Delamination Analysis By Using Cohesive Interface Elements In Laminated Composites." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611005/index.pdf.
Повний текст джерелаDatta, Sidhyartha. "Investigation of the micromechanics of delamination in fibre reinforced composites." Thesis, Imperial College London, 2005. http://hdl.handle.net/10044/1/7867.
Повний текст джерелаGreenhalgh, Emile Smith. "Characterisation of mixed-mode delamination growth in carbon-fibre composites." Thesis, Imperial College London, 1998. http://hdl.handle.net/10044/1/7975.
Повний текст джерелаDyson, Igor Niladri. "The fracture behaviour of carbon fibre/polyetheretherketone composites." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309100.
Повний текст джерелаZhao, Dongming. "Interlaminar fracture behavior of woven fabric composites and mode III delamination analysis." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/10075.
Повний текст джерелаPelegri, Assimina A. "Delamination growth behavior in cross-ply composites under compressive cyclic (fatigue) loading." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/12004.
Повний текст джерелаLa, Saponara Valeria. "Crack branching in cross-ply composites." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/11973.
Повний текст джерелаFerrie, Catherine H. "Effect of transverse shear on the postbuckling and growth characteristics of delaminated composites." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/12355.
Повний текст джерелаBhat, Narendra Venugopal. "Delamination suppression in graphite/epoxy composites via efficient use of film adhesive layers." Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/42979.
Повний текст джерелаEl-Senussi, A. K. "Interlaminar delamination in unidirectional carbon epoxy composites induced by static and fatigue loading." Thesis, University of Bristol, 1986. http://hdl.handle.net/1983/5db427ad-9653-4c84-999d-59a5a511ef30.
Повний текст джерелаFox, Bronwyn Louise, and blfox@deakin edu au. "The Manufacture, Characterization and Aging of Novel High Temperature Carbon Fibre Composites." The Australian National University. Faculty of Engineering and Information Technology, 2001. http://thesis.anu.edu.au./public/adt-ANU20011207.114246.
Повний текст джерелаGovender, Reuben Ashley. "Characterisation of Glass Fibre Polypropylene and GFPP based Fibre Metal Laminates at high strain rates." Doctoral thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/25150.
Повний текст джерелаLee, Hao. "Damage modelling for composite structures." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/damage-modelling-for-composite-structures(ee416524-935c-487d-bcd5-282875e6027a).html.
Повний текст джерелаCosta, Elisabete Fernandez Reia Da. "Liquid moulding of carbon nanoparticle filled composites." Thesis, Cranfield University, 2011. http://dspace.lib.cranfield.ac.uk/handle/1826/7276.
Повний текст джерелаMoradi, Shapour. "Application of differential quadrature method to the analysis of delamination buckling of laminated composites." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0008/NQ39323.pdf.
Повний текст джерелаKiefer, Konstanze. "Simulation of high-cycle fatigue-driven delamination in composites using a cohesive zone model." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/25155.
Повний текст джерелаBrown, Kevin S. "Embedded Distributed Fiber Optic Strain Measurements for Delamination Detection in Composite Laminates." University of Dayton / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1543330547266239.
Повний текст джерелаPoutord, Antoine. "Étude du perçage à sec de l'empilage Ti6Al4V/Composite fibre de carbone." Thesis, Paris, ENSAM, 2014. http://www.theses.fr/2014ENAM0149/document.
Повний текст джерелаThe aeronautic field has stronger and stronger requirements so the use of materials for structures has been unavoidable. That’s why carbon fiber composite is appeared in plane structures, used with elements in titanium alloy, and most part of them in Ti6Al4V. These materials are also dispatched in stacks and are drilled in a “one shot” operation, in the aim of being assembled with rivets or bolts. Through the industrial point of view, many problems are highlighted by this operation, generating several over costs. Technologic and scientific locks linked with this operation will be analyzed in this study.The knowledge of local stresses exerted by the tool on the machined matter is the first point allowing the improvement of the understanding of phenomenon that occurs during cutting. Few processes will be experimented to determine stresses submitted by the tool during drilling with accuracy. In the aim of completing the knowledge of the cutting operation, the analysis of the temperature inside the drill is needed. That’s why different experimental devices of thermal measurement are developed.These devices have allowed instrumented machining of holes in each material separately and in the stack of Ti6Al4V/CFRP in order to understanding phenomenon that occur during this operations
Patel, Kinjalkumar. "Functional multi-scale composites by coating of fibrous reinforcements." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/functional-multiscale-composites-by-coating-of-fibrous-reinforcements(92842a85-98a9-44f6-9bd7-dcbd13ab57b6).html.
Повний текст джерелаClarke, M. P. "The effect of low velocity impact damage on the compressive properties of carbon fibre reinforced composites." Thesis, University of Bristol, 1997. http://hdl.handle.net/1983/98ed8240-fdad-4241-87ab-ec69d9d35532.
Повний текст джерелаDupleix-Couderc, Chloé. "Sur une stratégie multi-échelle d'analyse des grands délaminages en dynamique transitoire." Thesis, Cachan, Ecole normale supérieure, 2011. http://www.theses.fr/2011DENS0013/document.
Повний текст джерелаThe part of composite materials in aeronautic structures is increasing due to their specific properties and the mass reduction they enable. Accurate numerical simulations are thus needed in order to design these structures, particularly to verify if they could resist dynamic charges such as soft bodies impact. Nevertheless, using a refined model to represent phenomenon such as delamination leads to computing time and dofs number incompatible with an industrial context. The aim of the present work is to propose a multi-scale method in space and time to solve dynamic impact problems on laminate structures. A domain decomposition method for dynamic problems is first used to couple different kinds of models and time discretisations. A refined model for the laminate is used in the degradating areas only - elsewhere, a coarser representation using 3D-shell elements is used. This approach reduced the cost of the simulation giving accurate results. To avoid a remeshing due to delamination propagation within the structure, a multi-scale method is then proposed. A global 3D shell elements mesh for the whole structure is defined. Local meshes based on a refined representation of the laminates are used only if required. Coupling between global and local representation is done using velocity field
Maillet, Irène. "Propagation de délaminage par fatigue vibratoire dans un matériau composite." Thesis, Toulouse, ISAE, 2013. http://www.theses.fr/2013ESAE0010/document.
Повний текст джерелаBecause of their lightness, stress adaptive design and strong stiffness, composite materials are more and more used in aeronautics. Aeronautical structures are submitted to vibrations during their service life due to aerodynamic turbulent flow around the structure. The current static design of composite aircraft covers fatigue loading cases. But with the need to more and more lighten the structure, and the knowledge increase in material behavior, the static reserve factors will be reduced in the near future and sonic fatigue will become a major issue. It will be necessary to evaluate the possibility of a delamination propagation in a composite structure due to a manufacturing error or to an impact. In this context, a method has been proposed to study the propagation of a delamination under vibratory loading. Firstly, tests to characterize the propagation of delamination under vibration loading have been developed and validated for the two main failure modes. The effects induced by the highfrequency loading, self-heat generation and high speed loading, were considered in the elaboration of these tests and in the data reduction. Then, numerical tools have been developed to allow the simulation of a delaminated structure under vibratory loading in order to study the delamination propagation. Using experimental and numerical approaches and the material data identified, the analysis could be conducted on a real case of aircraft structure. A vibration fatigue test on a ply-drop structure has been achieved. The evolution of delamination during the test is adequately modelized by the numerical model
Turon, Travesa Albert. "Simulation of delamination in composites under quasi-static and fatigue loading using cohesive zone models." Doctoral thesis, Universitat de Girona, 2006. http://hdl.handle.net/10803/7764.
Повний текст джерелаEl model proposat és un model de dany termodinàmicament consistent que permet simular la delaminació en composites sota càrregues variables. El model es formula dins el context de la Mecànica del Dany, fent ús dels models de zona cohesiva. Es presenta un metodologia per determinar els paràmetres del model constitutiu que permet utilitzar malles d'elements finits més bastes de les que es poden usar típicament. Finalment, el model és també capaç de simular la delaminació produïda per càrregues de fatiga.
A design tool for the analysis of delamination in laminated composites was developed. The design tool is developed using the damage-tolerance concept to predict both delamination initiation and growth. Therefore, the model developed can be used to perform either strength or damage-tolerance verification of new components, and can be used to assess the necessity to repair or replace in-service components. The model developed can be used either to simulate quasi-static or fatigue loading.
A thermodinamically consistent damage model is proposed for the simulation of delamination in composite materials under variable-mode loading. The model is formulated in the context of Damage Mechanics by means of the Cohesive Zone Model concept. Moreover, a methodology to determine the parameters of the constitutive model is proposed. The methodology presented allows the use of coarser meshes that is usually admissible. Finally, the model has been enhanced to simulate high cycle fatigue.
Stevanovic, Dejan, and dejan@mso anu edu au. "Delamination Properties of a Vinyl-Ester/Glass Fibre Composite Toughened by Particulate-Modified Interlayers." The Australian National University. Faculty of Engineering and Information Technology, 2002. http://thesis.anu.edu.au./public/adt-ANU20030421.212730.
Повний текст джерелаTroulis, Emmanouil. "Effect of Z-Fiber® pinning on the mechanical properties of carbon fibre/epoxy composites." Thesis, Cranfield University, 2003. http://dspace.lib.cranfield.ac.uk/handle/1826/107.
Повний текст джерелаZubillaga, Eceiza Lierni. "Experimental and analytical study of delamination caused by free-edges and matrix cracks in laminated composites." Doctoral thesis, Universitat de Girona, 2014. http://hdl.handle.net/10803/284759.
Повний текст джерелаEn los últimos años se ha incrementado el uso de materiales compuestos en diferentes campos de la tecnología. Este tipo de materiales presentan varios tipos de fallo, siendo uno de ellos la deslaminación o fallo interlaminar. La deslaminación puede reducir la capacidad de carga de los compuestos y puede comprometer la integridad estructural. En la actualidad, se puede predecir la deslaminación mediante herramientas numéricas, pero estas implican un alto coste computacional que imposibilita su utilización en las primeras etapas del diseño de un componente estructural. En esta tesis se aborda esta problemática, proponiendo métodos de cálculo de bajo coste computacional que permiten predecir la deslaminación en las primeras etapas del diseño estructural. Se han desarrollado métodos de análisis para dos distintos tipos de deslaminación: por efectos de borde y provocada por grietas en la matriz, y se han validado mediante una campaña experimental
Zhang, Chao. "Random delamination of graphite/epoxy laminated composites : stress analysis, failure criteria, experimental characterization and stochastic modeling." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ63992.pdf.
Повний текст джерелаAbisset, Emmanuelle. "Un mésomodèle d’endommagement des composites stratifiés pour le virtual testing : identification et validation." Thesis, Cachan, Ecole normale supérieure, 2012. http://www.theses.fr/2012DENS0035/document.
Повний текст джерелаIn order to provide reliable numerical simulations for the design of composite structures, both accurate, physically based material models and high performance numerical codes are necessary. The aim of this thesis is to validate one of these models: the LMT damage mesomodel for laminated composites. A new validation process, based on the evolution of the degradation mechanisms in the material up to failure, is defined. This approach is then applied on two chosen test cases: open-hole tensile tests and static indentation tests, focusing on the scaling effects. The first test case highlights the model capabilities to mirror the failure mode change with ply thickness: from a fiber breaking dominated failure to a delamination dominated one. Nevertheless, it also underlines one of the model weaknesses: the bad representation of localised damage such as splits. A study of the transverse cracking, the delamination and their interaction allow to improve the capabilities of the model and to understand in depth the role of these mechanisms in the structure failure. Concerning the static indentation, a complete experimental campaign was built and performed in collaboration with the ACCIS laboratory in Bristol. It brings out different damage evolution depending on plate thickness that can be used to validate the model. The first simulations performed show that the model does not manage to mirror all the experimental observations, and underline numerical limitations of the finite elements code used
Thiagarajan, C. "Smart characterisation of damage in carbon fibre reinforced composites under static and fatigue loading condition by means of electrical resistivity measurements." Thesis, Cranfield University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309660.
Повний текст джерелаTreutenaere, Sylvain. "Modélisation du comportement des composites stratifiés à préformes textiles avec prédiction du délaminage pour des simulations d'impact." Thesis, Valenciennes, 2016. http://www.theses.fr/2016VALE0001/document.
Повний текст джерелаCarbon Fabric Reinforced Polymers (CFRP) will soon used in high volume automotive production in order to reduce the vehicle weight. For safety and design reasons, their complex behaviours under low-speed impacts, such as pedestrian impacts, need to be accurately modelled and predicted by finite element simulations. For this purpose, a material model dedicated to explicit finite element simulations has been developed and implemented in a commercial finite element code. Subject to low-speed impacts, the CFRP shows four different physical mechanisms which alter the initial stiffness of the material: intralaminar matrix cracks, fibre failure, delamination and strain-rate sensitivity. The intralaminar damage is modelled through constitutive equations based on the continuum damage theory. It is based on the Onera Damage Model, but with the consideration of friction mechanisms between crack lips in order to represent the hysteresis loops in case of cyclic loading. The strain-rate sensitivity is introduced by means of the rheological generalised Maxwell viscoelastic model. Regarding the fibre damage, a failure criterion based on the strain of the fibre direction is introduced. The energy release due to the fibre failure is also regularised thanks to a smeared crack approach. Finally, in order to welldescribed the out-of-plane behaviour, such as bending, of a laminated CFRP material, a recomputation of a realistic strain field through-the thickness of the laminate is introduced at level of the material model. Based on strain energy equilibrium between usual shell element theory and higher-order zigzag theory, this formulation is able to consider delamination at ply interfaces by using only one shell element through-the-thickness of a laminate. In addition, the model is placed in a total Lagrangian framework to ensure both objectivity and material coherence. The identification procedure, with the needed experimental tests, as well as validation tests and experimental/numerical correlations are given for all physical mechanisms previously described. Finally, this model is evaluated through the behaviour prediction of an industrial structure
Davis, Richard Anthony. "The Effects of a Damage Arrestment Device on the Mechanical Behavior of Sandwich Composite Beams Under Four-Point Bending." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/506.
Повний текст джерелаBlanco, Villaverde Norbert. "Variable mixed-mode delamination in composite laminates under fatigue conditions: testing & analysis." Doctoral thesis, Universitat de Girona, 2005. http://hdl.handle.net/10803/7760.
Повний текст джерелаMost of the failures in structural elements in use are a consequence of mechanical fatigue. Therefore, fatigue is a decisive factor in designing durable mechanical elements. In laminated composite materials, the fatigue process involves different damage mechanisms that result in the degradation of the material. One of the most important damage mechanisms is the delamination between plies of the laminate. In aeronautical applications, composite plates are sensitive to impact and delamination occurs readily in composite laminates on impact. Many composite components have curved shapes, tapered thickness and plies with different orientations, which make the delamination grow with a mode mix that depends on the extent of the crack. Thus, delaminations generally grow under varying mode mix. It is therefore important to develop methods that can characterise subcritical, mixed-mode growth in fatigue delamination. The main objective of the present investigation is the characterisation of the variable mixed-mode delamination in composite laminates under fatigue conditions. To this end, a mixed-mode fatigue delamination model is proposed. Oppositely to the mixed-mode fatigue delamination models present in the literature, the proposed model takes into account the non-monotonic variation of the propagation parameters with the mode mix observed in different experimental data. Moreover, the mixed-mode end load split (MMELS) test, which main characteristic is that the propagation mode of the interlaminar crack varies with the crack extent, is analysed. Two theoretical approaches present in the literature are considered. However, the resulting expressions for the MMELS test are not equivalent and the differences between approaches can be up to 50 times. A more accurate alternative analysis of the MMELS test is carried out in the present study for comparison. The alternative analysis is based on the finite element method and the virtual crack closure technique. Significant findings are found for precise materials characterisation using the MMELS test. A MMELS test rig is also designed and built. Different specimens of essentially unidirectional carbon/epoxy laminates are tested for the experimental characterisation of fatigue delamination under varying mode mix. A fractographic analysis is also conducted in some of the delaminated fracture surfaces. The experimental results are compared to the predictions of a proposed model for the fatigue propagation of interlaminar cracks.
Charalambous, Georgia. "The effect of temperature on mixed-mode fracture toughness and fatigue delamination growth of fibre-reinforced composites." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.682234.
Повний текст джерелаJorcin, Jean-Baptiste Pébère Nadine. "Spectroscopie d'impédance électrochimique locale caracterisation de la delamination des peintures et de la corrosion des alliages Al-Cu /." Toulouse : INP Toulouse, 2007. http://ethesis.inp-toulouse.fr/archive/00000494.
Повний текст джерелаMinnaar, Karel. "Experimental and numerical analyses of damage in laminate composites under low velocity impact loading." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/15812.
Повний текст джерелаCareddu, Matteo. "Characterization of mode I disbonding behaviour of carbon/epoxy composites bonded with two adhesion qualities." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/6355/.
Повний текст джерелаSatthumnuwong, Purimpat. "Approche expérimentale et numérique de la rupture des assemblages collés de composites stratifiés." Thesis, Dijon, 2011. http://www.theses.fr/2011DIJOS052/document.
Повний текст джерелаAdhesive bonding of composite materials has undeniable advantages over other methods such as bolting or riveting. However, one of the difficulties encountered by designers is the prediction of the failure level and failure mode of these adhesively bonded assemblies. In the case of composite laminates, one of the factors acting on the bonded joint behaviour is the stacking sequence, but works presented in the literature do not separate global effects (membrane and bending stiffness modification) and local effect (ply orientation near the adhesive layer). This study deals with the characterization of such effects in the case of single lap joints of carbon/epoxy laminates. In order to isolate the local effects, specific quasi isotropic quasi homogeneous stacking sequences are used. When stiffness properties are maintained constant, strength variations of more than 30 % are observed. Tests performed with a symmetric laminate with bending anisotropy show that the bending stiffness plays also an important role in the joint behaviour. Closed form models are able to predict global effects with a good accuracy but are inappropriate when local effects occur. The use of finite element models can account for these phenomena, by explicitly modelling the laminate plies near the adhesive layer and introducing delamination between these plies with a cohesive zone model. This model is used to perform a parametric study of the joint geometry and to produce a failure envelope according to the orientation of the loading
Vandellos, Thomas. "Développement d’une stratégie de modélisation du délaminage dans les structures composites stratifiées." Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14380/document.
Повний текст джерелаThe carbon/epoxy laminated composites of unidirectional plies are strongly used in order to reduce the weight of aeronautical structures while at the same time proposing good structural properties. However, the advantages of this kind of material are not fully exploited due to the lack of confidence in damage models, like ones concerning delamination. Then, the purpose of this work was the development of a strategy to model delamination in laminated composite structures. This strategy was based on the development of a cohesive zone model taking into account the ingredients necessary to the well description of the onset of delamination and the crack growth: (i) an onset criterion with an out-of-plan compression/shearing reinforcement, (ii) a propagation law describing the evolution of the fracture toughness as a function of mixed mode ratio and (iii) the inter/intralaminar coupling. To identify this new model, an efficient identification procedure, basing on a tensile test on notched specimen, has been proposed. This identification procedure has demonstrated that the fracture toughness seems to be independent of (i) the orientation of plies closed to the interface and (ii) the stacking sequence. Furthermore, to describe the evolution of the fracture toughness, a new propagation law adapted to carbon/epoxy material has been proposed. Finally, the strategy to model delamination, completed by a calculation strategy, has been applied on several structural cases to prove its contributions and its first limitations
Motamedi, Damoon. "Nonlinear XFEM modeling of delamination in fiber reinforced composites considering uncertain fracture properties and effect of fiber bridging." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44630.
Повний текст джерелаDurix, Lucas. "On the design of a new test method to characterize the delamination of thermosetting polymer under thermal mixed mode loading." Valenciennes, 2010. http://ged.univ-valenciennes.fr/nuxeo/site/esupversions/bd1267ad-5bd0-4890-b878-4443d6031356.
Повний текст джерелаLa propagation des fissures dans les circuits intégrés est l’une des causes principales de défaillance de ces circuits. Sur le marché automobile fortement concurrentiel, les défaillances ne sont pas permises, et la fiabilité demeure un critère pouvant faire la différence pour gagner des parts de marché. Pour cette raison, de nombreux efforts et recherches ont vu le jour durant les dernières décennies. Dans le cas des applications liées à l’automobile, les composants électroniques sont confrontés à de lourdes contraintes, telles que vibrations, importants changements de température, projections d’eau ou de dérivés pétroliers, etc. Les variations de température génèrent en particulier des déformations thermiques souvent incompatibles au niveau des interfaces entre matériaux, ce qui provoque dans les circuits intégrés le décollement des conducteurs cuivrés de l’enrobage polymérique utilisé pour la protection du composant (délaminage). Le délaminage aboutit par la suite à la fissuration propre de l’encapsulant puis à la défaillance du composant. L’amélioration de la fiabilité des composants requiert par conséquent de pouvoir prédire le délaminage aux interfaces cuivre/matériau d’encapsulation. Tel que démontré dans ces travaux, la ténacité interfaciale dépend de plusieurs influences. Une caractérisation complète requiert de nombreux tests, mettant en jeu différents types d’appareillages et d’éprouvettes, ce qui génère de nombreux coûts et un temps d’exécution important. Une méthode de test à faible coût est proposée dans ce document pour la caractérisation des interfaces cuivre/encapsulant dans les différentes conditions évoquées. Cette méthode a été mise en pratique avec succès pour caractériser un matériau d’encapsulation classiquement utilisé dans l’industrie automobile. L’influence de la mixité des modes de rupture, de la température, de la vitesse de chargement ainsi que de l’humidité ont été étudiées. Les techniques habituelles en mécanique de la rupture de corrélation résultats expérimentaux-simulations ont été utilisées pour déterminer le taux de restitution d’énergie critique dans les différents cas. La ténacité de l’interface cuivre/matériau d’encapsulation s’est révélée suivre un comportement viscoélastique, incluant des propriétés propres de superposition temps-température. Les paramètres interfaciaux obtenus ont finalement été définis dans l’outil de simulation MEF Abaqus. Ce dernier a d’ailleurs été l’objet de nombreuses vérifications en ce qui concerne la simulation des problèmes de délaminage des matériaux viscoélastiques. Dans le cas de la fissuration entre deux matériaux hétérogènes, la description analytique des champs de contrainte et de déformation en pointe de fissure fait appel à une longueur de référence. Le choix de cette longueur de référence est abordé dans ce document. Cette dernière est déterminée expérimentalement pour les différentes températures testées
Mahmood, Ali Hasan. "Optimising the lamination properties of textile composites." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/optimising-the-lamination-properties-of-textile-composites(6a215f92-e200-4e30-8b72-7f599a5e95f3).html.
Повний текст джерелаSimlissi, Essossinam. "Modeling of delamination and interface strength in printed circuit boards." Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0326.
Повний текст джерелаIn this thesis, the identification of the interface strength in Printed Circuit Boards (PCBs) is assessed. A PCB is a passive component, which allows to interconnect electronic components soldered on the outer layers in order to realize a complex electronic system. It is a multiple layer assembly made of woven composite and copper foil. Copper plays a major role in Printed Circuit Boards (PCBs) since it is the carrier of the electrical information. During its lifetime, the PCB undergoes a large number of thermal cycles, which can lead to the failure of copper path. In addition, it has been detected that the use of certain combinations of based materials leads to delamination, which limits the PCB service-life. The measurement of interface strength between copper layer and composite substrate is critical and the usual method for measuring the interface properties in PCB industry is the peel test. The PhD is divided in three main parts. In the first experimental part, peel tests at various peel angles are performed using specimens, which consist of a copper foil bonded on a woven composite substrate. Interface separation between the copper film and the composite substrate is observed. During the test, the peel force per unit width and the copper film radius at steady state are measured. Next, a theoretical analysis of the peel test for an elastic-plastic material is proposed. A precise definition of the work done by bending plasticity for a particular class of material response is established. Indeed, we have extended previous works of the literature by considering that the plastic hardening behavior of the film is modeled by a Voce type law. Finally, finite element (FE) simulations of peeling are conducted at various peel angles by considering that the copper material response is elastic-plastic. The isotropic hardening is identified based on uni-axial tensile tests. The woven composite is assumed to remain elastic with an orthotropic response. The interface is modeled by cohesive elements using a bilinear traction separation law. FE results are compared to experimental data. It is shown that the peel force and the film curvature are predicted accurately, for a large range of peel angles. 125 Therefore, from the dialog between finite element calculations and experiments, the interface fracture energy is obtained