Дисертації з теми "Delamination mechanism"
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Blandon, Omar Ali. "Mechanism of Delamination of Electrospun Adhesive Nanofibers." University of Akron / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=akron1446477512.
Повний текст джерелаYamanaka, Tadayoshi. "Delamination modelling and toughening mechanism of a woven fabric composite." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104701.
Повний текст джерелаLes méthodes de simulation numériques efficaces et exactes pour l'analyse de l'endommagement et la prédiction de vie en fatigue des matériaux composites sont essentielles pour l'industrie. Les problèmes surviennent dans le développement d'une telle méthode de simulation en raison des restrictions des méthodes numériques, c'est-à-dire, modélisation de la délamination et compréhension des mécanismes de rupture de composites à base de fibres tissées.Pour developer un modèle de délamination efficace et précis, une nouvelle méthode est proposée dans cette étude en utilisant la method des éléments finis. La méthode proposée n'exige pas de degrés-de-liberté supplémentaires pour créer de nouvelles sufaces de fissures/ délaminations. Le résultat de simulation de délamination par la méthode proposée est comparé avec un logiciel d'éléments finis commercial, et les résultats se comparent bien.Les mécanismes d'endommagement d'un composite tissé typique "five-harness satin" sont le sujet d'une étude. Ceci est fait en créant un modèle d'éléments finis "méso-échelle" en utilisant l'exemple d'un spécimen d'essais Mode 1 (spécimen DCB). Le tissu est modélisé avec les trajectoires exactes des fibres dans les deux directions, et les espaces entre les fibres sont remplis de la matrice. Des éléments cohésifs sont insérés entre la matrice et les interfaces des fibres. Les composants méso-échelles sont joints avec des parties homogènes qui sont utilisées pour modéliser des régions où aucun endommagement n'est prévu. La combinaison des ces parties constitue un modèle multiéchelle d'un spécimen DCB. Les résultats de simulation d'un essai sont en accord avec les résultats expérimentaux, du côté conservateur. Le mécanisme renforçant des ultant du type de tissage a été démontré.Cette étude contribue à la science en présentant de nouvelles méthodes pour modéliser les fissures et pour comprendre les mécanismes d'endommagement des composites tissés pendant la croissance des délaminations.
Tran, Tony D. "An Investigation of Initially Delaminated Composite Sandwich with Delamination Arrest Mechanism under Buckling Loading." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/428.
Повний текст джерелаWhitcomb, J. D. "Instability-related delamination growth of embedded and edge delaminations." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/77755.
Повний текст джерелаPh. D.
Xia, Qingxi 1973. "Mechanics of inelastic deformation and delamination in paperboard." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8334.
Повний текст джерелаIncludes bibliographical references (p. 233-236).
Paperboard is one of the most widely used materials. The inelastic deformation of paperboard plays a crucial role during many manufacturing processes (e.g., the converting process whereby paperboard is converted into a product such as a milk carton by punching and subsequent folding) and during in-service applications. There is a scarcity of constitutive models describing inelastic behavior of paperboard under complex loading, despite the paper industry's great need of analytical tools to aid the design and manufacturing of better paperboard products. In this thesis, two constitutive models are developed to model the highly anisotropic, elastic-plastic behavior of paperboard/paper: (1) A three-dimensional elastic-plastic interface constitutive model is developed to model the out-of-plane delamination behavior of paperboard. The onset of interface separation is controlled by a limit surface in the normal-shear traction space. The limit surface is taken to shrink with a monotonically-increasing scalar internal variable reflecting damage associated with the history of inelastic relative interface displacement. (2) A three-dimensional, anisotropic continuum constitutive model is developed to model the in-plane elastic-plastic deformation of paper and paperboard. The proposed initial yield surface is directly constructed from the yield strengths measured in various loading directions and the corresponding ratios of plastic strain components. An associated flow rule is used to model the plastic flow of the material. Anisotropic strain-hardening of yield strengths is introduced to model the evolution of the yield surface with inelastic strain.
(cont.) The two constitutive models are implemented into finite element software to enable the simulation of paperboard mechanical behavior under complex, finite deformation. The models are shown to be capable of accurately capturing both the out-of-plane delamination (via the interface model) and the anisotropic in-plane elastic-plastic (via the continuum in-plane model) behavior of paperboard under complex loading. The two models are combined to simulate the mechanics of a converting process (creasing and subsequent folding) of paperboard. The simulations agree well with corresponding experimental observations. In particular, the underlying mechanisms of damage and delamination development during creasing and subsequent folding are predicted well; the macroscopic response of the bending moment vs. bending angle also agrees with experimental data. This research provides physically based three-dimensional material models of the anisotropic, elastic-plastic deformation of paperboard that enable the computational design of paperboard process and product design.
by Qingxi Steve Xia.
Ph.D.
Johansson-Näslund, Markus. "Numerical analysis of paperboard delamination using cohesive elements." Thesis, KTH, Hållfasthetslära, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-277779.
Повний текст джерелаEn ny testmetod för att mäta skjuvstyrkan för modus III delaminering av kartong studeras i syftet att reducera testutrustningens storlek. Testmetoden, som använder sig av en delad konsolbalk (SCB), mäter skjuvstyrkan indirekt genom brottresistansen. Metodiken är baserad på det standardiserad konsolbalks testet DCB, var två balkar är sammankopplade och som används för att mäta delaminering styrkan i kartongens normala riktning. Studien baseras på analyser med finita element, var kohesiva element implementeras för att prediktera brottbeteendet. En experimentell utvärdering av testmetoden genomfördes i en förstudie mellan Karlstads, Skövdes och Lunds universitet tillsammans med Tetra Pak. Experimenten gjordes både för DCB- och SCB-testet, och för att utvärdera brottbeteendet användes de kohesiva lagarna som presenterats av Tryding & Ristinmaa (2017). De experimentella resultaten används som bas vid utvärdering av analyserna. För att modellera spricktillväxten implementeras de kohesiva lagarna i det kommersiella FEM programmet Abaqus genom ett användar specificerat element (UEL). Från analyserna av DCB-testet visas det att det är möjligt att simulera modus I sprickbildning i kartong genom implementering av en specifik kohesive lag. Simuleringarna av DCB-testet stämmer väl överens med de experimentella resultaten. Resultaten från SCB-analyserna visar däremot på ett avvikande beteende från experimenten genom att underskatta skjuvstyrkan. Det noteras i analyserna av SCB-testet att märkbara deformationer i både den första skjuvriktningen och normal riktningen uppkommer, vilket förhindrar att ren skjuvbelastning i modus III erhålls. Baserat på analysernas resultat indikeras det att den nuvarande konfiguration för SCB-testet inte ger ren skjuvbelastning i modus III och underskattar därför kartongens faktiska skjuvstyrka. Det visas också att en 400 mm reducering av SCB-geometrins längd inte har någon märkbar påverkan på de kohesiva egenskaperna. Genom att ändra den initiala spricklängden är det möjligt att ytterligare reducera SCBgeometrins längd. För att försäkra sig om att sprickas tillväxt förblir stabil bör däremot längden på kartongen överstiga 300 mm. Att minska den initiala spricklängden och bredden på kartongen verkar generellt bidra till lägre deformationer i normal riktningen och ett resultat som ligger närmare de experimentella. Tryding, J. & Ristinmaa, M. (2017). Normalization of cohesive laws for quasi-brittle materials. Engineering Fracture Mechanics, 178, 333-345. doi:10.1016/j.engfracmech.2017.03.020
Dávila, Carlos G. "Delamination initiation in postbuckled dropped-ply laminates /." This resource online, 1991. http://scholar.lib.vt.edu/theses/available/etd-07282008-134842/.
Повний текст джерелаWang, Bin. "Local delamination failure of thin material layers." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/25128.
Повний текст джерелаDimant, Ron A. "Damage mechanics of composite laminates." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338020.
Повний текст джерелаHuang, Haiying. "Single and multiple delamination behavior in composite plates." Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/12541.
Повний текст джерелаDávila, Carlos G. "Delamination initiation in postbuckled dropped-ply laminates." Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/38915.
Повний текст джерела劉英傑 and Yingjie Liu. "Damage characterization of multi-directional laminates with matrix cracks and delamination." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31235104.
Повний текст джерелаLiu, Ying-jie. "Damage characterization of multi-directional laminates with matrix cracks and delamination /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B16504434.
Повний текст джерелаChen, Zi Qi. "Delamination buckling of pressure-loaded laminated cylindrical shells and panels." Diss., Georgia Institute of Technology, 1987. http://hdl.handle.net/1853/21227.
Повний текст джерелаZhang, Qiuting. "Mechanics and Functionality of Extreme Mechanical Instabilities through Buckling Driven Delamination." Diss., Temple University Libraries, 2019. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/587760.
Повний текст джерелаPh.D.
Mechanical instabilities such as wrinkling and buckling-driven delamination in thin film-substrate systems have historically been considered as one of structural failure mechanisms, which should be avoided. The past decade has witnesssed rapid growth in harnessing such surface instabilities for a wide range of tunable surface related properties and functionalities, especially in soft materials on small scales. Compared to extensively studied wrinkling on soft substrates and localized buckling driven delamination on stiff substrates, the fundamental mechanics underpinning ordered buckle-delamination on soft substrate over large area and its guidance for potential implications in engineering innovation remain largely to be explored. This thesis aims to partially bridging such a knowledge gap. In this thesis, I exploit how to generate the controllable and globally periodic delaminated buckling patterns in thin films on highly prestrained elastomeric substrates, and then explore the fundamental mechanics of this spontaneous extreme buckling driven periodic delamination, as well as its implications in design of extremely stretchable electronics and interfacial mechanical properties measurement. Compared to wrinkling, one of the benefits of extremely buckling driven delamination is the extraordinarily high aspect ratio of buckles. The large surface roughness and high local curvature could potentially enable extreme surface topographies related properties, such as adhesion, wetting, friction, and optics, as well as augment the extreme stretchability in stretchable optical and electronic devices. In the aim of harnessing this extreme buckling driven delamination, I first explore the formation and evolution of extraordinarily high-aspect-ratio delaminated buckles of thin films on 400% pre-strained elastomers, as well as uncovered the underlying deformation mechanism through combining quantitative theoretical analysis and experimental and numerical approaches. A theoretical framework is developed to describe the formation and evolution process of periodic delaminated buckles, which includes three deformation stages, i.e. onset of localized blisters (Stage I), growth and propagation of delamination (Stage II), and post-buckling after delamination arrest (Stage III). I show that under extreme large compressive strain, the profile of periodic blisters changes from sinusoidal shape to jig-saw-like shape with relative high aspect ratio, which have potential applications for design of extremely stretchable electronics. Equipped with the fundamental mechanics of buckle-delamination in thin films, I then exploit harnessing the spontaneous buckling driven periodic delamination to achieve high stretchability in both metal and silicon films. Experimentally I observe periodic buckle-delaminated patterns over large area, accompanied by highly ordered transversely cracking patterns, which can be theoretically predicted by simple crack fragments model. I hypothesize that when the width of ribbons is set to be equal or smaller than the theoretically predicted crack fragment width, there would be no cracking fragmentation. This criteria for designing crack-free micro-ribbons is further validated by related experiments. Guided by the validated criteria, I successfully design crack-free and spontaneous delaminated ribbons on highly prestrained elastomer substrates, which provides a high stretchability of about 120% and 400% in Si and Au ribbons, respectively. I further extend the buckling instability-based metrology to systematically measure the mechanical properties of 2D organic conjugated polymer nano-films, which have tremendous promising applications in organic integrated circuits, solar cells, and stretchable devices. I develop a new fabrication strategy to generate buckle-delaminated free-standing organic conjugated polymeric (P3BT/C60) nanosheets. Through both experiments and theoretical analysis, I show that the free-standing buckle-delaminated organic P3BT/C60 nanosheets have significant advantages over the traditional spin-coated wrinkled nanosheets, including the enhanced mechanical properties, a higher level of stretchability with lower electrical resistance, and a wider range of controllable wettability modulation.
Temple University--Theses
Yilmaz, Suphi. "Buckling Driven Delamination Of Orthotropic Functionally Graded Materials." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/3/12607836/index.pdf.
Повний текст джерелаs technology severe working conditions increase demands on structural materials. A class of materials which are developed to meet these increased demands is Functionally Graded Materials (FGMs). These are inhomogeneous structural materials which are able to withstand large temperature gradients and corrosive environment. Application areas of FGMs are in aerospace industry, nuclear reactors, chemical plants and turbine systems. FGMs have gradual compositional variation from metal to ceramic which give them mechanical strength, toughness and heat resistance. However under high temperature gradients, cracking problems may arise due to thermal stresses. In layered structures the final stage of failure may be delamination due to crack extension. The objective of this study is to model a particular type of crack problem in a layered structure consisting of a substrate, a bond coat and an orthotropic FGM coating. There is an internal crack in the orthotropic layer and it is perpendicular to material gradation of coating. The position of the crack inside the coating is kept as a variable. The steady-state temperature distribution between the substrate and the coating causes a buckled shape along crack face. The critical temperature change, temperature distribution, mixed mode stress intensity values and energy release rates are calculated by using Displacement Correlation Technique. Results of this study present the effects of geometric parameters such as crack length, crack position, etc as well as the effects of the type of gradation on buckling behavior and mixed mode stress intensity factors.
Loveridge, M. J. "The Scanning Kelvin probe applied to mechanisms of delamination in organic coated steels." Thesis, Swansea University, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637953.
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 джерелаMessenger, C. R. "Investigation of delamination and matrix cracking in quasi-isotropic GFRP laminates." Thesis, University of Surrey, 1996. http://epubs.surrey.ac.uk/842699/.
Повний текст джерелаIlomäki, M. (Marko). "Application of fracture mechanics in analyzing delamination of cyclically loaded paperboard core." Doctoral thesis, University of Oulu, 2004. http://urn.fi/urn:isbn:9514274008.
Повний текст джерелаCardanini, Alisha Ann. "Finite Element Analysis of Bi-Metallic Structures with Adhesive Delamination." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu150185598849201.
Повний текст джерелаOkubo, Hitoshi, Fumihiro Endo, Naoki Hayakawa, Hiroki Kojima, and Diaa-Eldin A. Mansour. "Partial Discharges and Associated Mechanisms for Micro Gap Delamination at Epoxy Spacer in GIS." IEEE, 2010. http://hdl.handle.net/2237/14531.
Повний текст джерелаOkubo, Hitoshi, Masahiro Hanai, Naoki Hayakawa, Hiroki Kojima, and Diaa-Eldin A. Mansour. "Physical Mechanisms of Partial Discharges at Nitrogen Filled Delamination in Epoxy Cast Resin Power Apparatus." IEEE, 2013. http://hdl.handle.net/2237/20739.
Повний текст джерелаGoyal, Vinay K. "Analytical Modeling of the Mechanics of Nucleation and Growth of Cracks." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/30006.
Повний текст джерелаPh. D.
Garcia, Jorge David Aveiga. "A delamination propagation model for glass fiber reinforced laminated composite materials." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18148/tde-31072018-143609/.
Повний текст джерелаO emprego de materiais compósitos na indústria aeroespacial tem sido gradualmente utilizado devido às suas características fundamentais, como peso leve e alta rigidez, que este tipo de material oferece. Tanto a ciência do material como o desenvolvimento tecnológico que se tem logrado, possibilitaram que estes materiais cumprissem com os requisitos de desempenho para aplicações em estruturas aeronáuticas e aeroespaciais, por tanto, o desenvolvimento de elementos de estruturas primárias usando materiais compósitos, passou a ser muito conveniente. É de extrema importância prestar atenção aos modos de falha que comprometem a performance dos materiais compósitos, uma vez que, estas falhas levam a uma perda de resistência e rigidez do laminado. A delaminação é um modo de falha presente na maioria de estruturas danificadas e pode ser desastroso, considerando que, a evolução dos defeitos interlaminares podem levar a estrutura a falhar seguido pelo colapso estructural. Diferentes técnicas são geralmente adotadas para prever, de maneira correta, o comportamento de estruturas danificadas, porém, devido à natureza complexa do fenômeno de falha, não existe um padrão estabelecido. O presente trabalho de pesquisa visa desenvolver um modelo de delaminação e de propagação da delaminação para estimar a evolução da falha interlaminar em materiais compósitos laminados e permitir a predição do comportamento do material com a evolução da delaminação. Ensaios experimentais auxiliados por normas ASTM foram realizados para determinar parâmetros do material, tais como, as taxas de liberação de energia de deformação, usando materiais compósitos laminados de matriz polimérica reforçada com fibra de vidro. O modelo de propagação da delaminação proposto, foi implementado como uma sub-rotina em linguagem FORTRAN (UMAT – User Material) com formulações baseadas na Mecânica da Fratura. Finalmente, o modelo foi compilado com o software comercial de Elementos Finitos, ABAQUSTM.
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 джерелаPilhagen, Johan. "The fracture mechanisms in duplex stainless steels at sub-zero temperatures." Doctoral thesis, KTH, Materialteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-133677.
Повний текст джерелаQC 20131108
Kuriakose, Sunil. "Analysis of damage in composite laminates under bending." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/12054.
Повний текст джерелаBarbieri, Ettore. "Meshfree methods for the analysis of composite materials." Thesis, University of Bath, 2010. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558846.
Повний текст джерелаChadha, Harpreet Singh. "Quantitative evaluation of thin film adhesion using the probe test." Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/35426.
Повний текст джерелаMaster of Science
Ghazali, Habibah. "Dual-Capsule Based Self-Healing of Epoxy and Carbon-Epoxy Laminated Composite." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/15387.
Повний текст джерелаAbdelal, Nisrin Rizek. "Effects of Voids on Delamination Behavior Under Static and Fatigue Mode I and Mode II." University of Dayton / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1365418463.
Повний текст джерелаCERIONI, AGOSTINO. "Simulation of delamination in composite materials under static and fatigue loading by cohesive zone models." Doctoral thesis, Università degli Studi di Cagliari, 2009. http://hdl.handle.net/11584/266000.
Повний текст джерелаAminjikarai, Vedagiri Srinivasa Babu. "An Automated Dynamic Fracture Procedure and a Continuum Damage Mechanics Based Model for Finite Element Simulations of Delamination Failure in Laminated Composites." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1242963775.
Повний текст джерелаMikulik, Zoltan Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "Application of fracture mechanics to predict the growth of single and multi-level delaminations and disbonds in composite structures." Publisher:University of New South Wales. Mechanical & Manufacturing Engineering, 2008. http://handle.unsw.edu.au/1959.4/41560.
Повний текст джерелаRenault, Michel. "Tolerance a l'endommagement de composites carbone-resine et stratifies t300-914." Paris, ENMP, 1988. http://www.theses.fr/1988ENMP0109.
Повний текст джерелаNg, Annie Yuhn-Chee. "The mechanics of cam-type femoroacetabular impingement." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:390fbe37-77a5-42da-aa61-5be8e9b90955.
Повний текст джерелаSwindeman, Michael James. "A Regularized Extended Finite Element Method for Modeling the Coupled Cracking and Delamination of Composite Materials." University of Dayton / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1324605778.
Повний текст джерелаNeely, Jared A. "Correlation of Stress Intensity Range with Deviation of the Crack Front from the Primary Crack Plane in both Hand and Die Forged Aluminum 7085-T7452." University of Dayton / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1557162451907811.
Повний текст джерелаBouquet, Jean-Baptiste. "Implementation of a robust solver for predicting highly localized deformations in microelectronics." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41112.
Повний текст джерелаGe, Yangyang. "Development of testing methods for characterization of delamination behavior under pure mode III and mixed modes in a laminated composite." Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30130/document.
Повний текст джерелаThe aim of this research work is to characterize the delamination behavior of laminate composite materials under the three pure modes and mixed modes, focusing especially on the complex issue of mode III. Both experimental and numerical works were performed, validating the existing and new testing methods. Correlation between the results obtained aims, on the one hand to better understand the distribution of strain energy release rates (GI, GII, GIII) along the crack front; on the other hand, to propose and improve testing methods, and to propose and validate simple approaches for determination of delamination toughness. Pure mode III testing methods are studied. Firstly, two kinds of Edge Crack Torsion tests were carried out, the distribution of GIII along the crack front were determined by finite element analysis (FEA) using virtual crack closure technique (VCCT). The performances of these tests are compromised by the drawbacks: (1) A participation of mode II component cannot be completely eliminated; (2) The distribution of GIII along the crack front is not uniform especially near the sides. After a study of existing tests, a novel mode III testing method was proposed, named Edge Ring Crack Torsion test (ERCT or ERC-III later). In the ERC specimen, the total absence of sides in the circular crack front leads to no edge effects. As a result, pure mode III delamination is achieved and the distribution of GIII along the crack front is quite uniform. In fact, the values of GIII along the crack front are nearly constant after optimizing and modifying the geometry of device in the original ERCT test. A closed-form solution proposed by Tada is applied to determine mode III delamination toughness. In ERCT test, the results calculated by Tada formula agree well with the ones calculated by VCCT when the distribution of GIII is relatively uniform. Actually, a numerical study shows that the distribution of GIII can be affected by different factors related to the nature of laminates tested, the geometry of test device and the geometry of the specimens. The interactive effect of above factors was also discussed in this study. In order to understand the influence of potential defaults on the performance of ERCT test, sensitivity study has been performed on the relative position of the crack front, the circularity of the crack front and the specimen shape. Optimum specimen's relative pre-crack geometry is given and a method for reducing the variation is provided. Then the application of ERC specimen was generalized to other pure delamination modes characterization. Pure mode I can be realized if ERC specimens are loaded in tension, named ERCTE or ERC-I, so can pure mode II if ERC specimens are loaded in flexion, named ERCF or ERC-II. The distribution of the strain energy release rates was also evaluated by FEA using VCCT. These tests keep most advantages of ERC-III test. Pure mode I and pure mode II delamination are achieved respectively and the distribution of GI or GII along the crack front is quite uniform. The realization of ERC-I, ERC-II and ERC-III allows to measure the toughness of each of three pure modes without any interference from geometry of specimens. Finally, we have studied numerically the feasibility to realize the delamination tests in mixed mode I+II, I+III and I+II+III by using ERC specimen. Firstly, the mixed mode ratio can be obtained in a large range by varying the geometry of the specimen and by combining loading modes. Secondly, no unwanted mode is presented for mixed mode I+II and mixed mode I+III; Thirdly, the distribution of strain energy release rates are not completely uniform but its variation is small enough to be accepted. In conclusion, ERC tests are promising testing methods for characterization of mixed mode delamination behavior. It will be possible to propose a mixed mode I+II+III delamination criterion based on the investigation by ERC tests in a close future
Seon, Guillaume. "Finite element-based failure models for carbon/epoxy tape composites." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/28117.
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
Rodriguez, George IV. "Finite Element Modeling of Delamination Damage in Carbon Fiber Laminates Subject to Low-Velocity Impact and Comparison with Experimental Impact Tests Using Nondestructive Vibrothermography Evaluation." DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1583.
Повний текст джерелаKulkarni, Mandar Madhukar. "Prediction of Elastic Properties of a Carbon Nanotube Reinforced Fiber Polymeric Composite Material Using Cohesive Zone Modeling." University of Cincinnati / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1235433423.
Повний текст джерелаMatheas, Jan. "Entwicklung von Finiten Schalenelementen zur Berechnung von Verstärkungen aus Textilbeton bei Flächentragwerken." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2007. http://nbn-resolving.de/urn:nbn:de:swb:14-1177589904936-74048.
Повний текст джерелаThis publication introduces, in a continuum-mechanical approach, the formulation of a mechanical model in connection with the transformation into a shell element using the finite element method for the simulation of the load-bearing behaviour of laminated shell structures thereby considering delamination as a type of damage. This multi-layer model is based upon the development of a geometrically nonlinear surface-related shell theory with shear-elastic behaviour and variable thickness, beginning with the complete kinematics of a multi-director theory. The surface relationship ensures a mechanical modelling which is adaptable for contact problems. A linear-elastic orthotropic material law, whose three-dimensionality is not restricted by the shell formulation, applies within the layers. The main focus of the thesis is on the development of a layer-bond model that can be adjusted for different materials. The debonding of layers – called delamination – is described by a simple stress criterion. Delamination is discretely taken into account by modifying the kinematic conditions. A contact model, called „inner contact“, that can be used to account for adhesion between layers, has been developed to describe the load-bearing behaviour after delamination has occurred. The present shell model is restricted to elastic material behaviour and can preferably be applied to such problems where small relative displacements are expected. The environment, in which this research has been conducted, established the primary of application area, which is the simulation of shell structures within a strengthening layer comprised of textile-reinforced concrete
Matheas, Jan. "Entwicklung von Finiten Schalenelementen zur Berechnung von Verstärkungen aus Textilbeton bei Flächentragwerken." Doctoral thesis, Technische Universität Dresden, 2005. https://tud.qucosa.de/id/qucosa%3A24873.
Повний текст джерелаThis publication introduces, in a continuum-mechanical approach, the formulation of a mechanical model in connection with the transformation into a shell element using the finite element method for the simulation of the load-bearing behaviour of laminated shell structures thereby considering delamination as a type of damage. This multi-layer model is based upon the development of a geometrically nonlinear surface-related shell theory with shear-elastic behaviour and variable thickness, beginning with the complete kinematics of a multi-director theory. The surface relationship ensures a mechanical modelling which is adaptable for contact problems. A linear-elastic orthotropic material law, whose three-dimensionality is not restricted by the shell formulation, applies within the layers. The main focus of the thesis is on the development of a layer-bond model that can be adjusted for different materials. The debonding of layers – called delamination – is described by a simple stress criterion. Delamination is discretely taken into account by modifying the kinematic conditions. A contact model, called „inner contact“, that can be used to account for adhesion between layers, has been developed to describe the load-bearing behaviour after delamination has occurred. The present shell model is restricted to elastic material behaviour and can preferably be applied to such problems where small relative displacements are expected. The environment, in which this research has been conducted, established the primary of application area, which is the simulation of shell structures within a strengthening layer comprised of textile-reinforced concrete.
Singh, Hitendra Kumar. "Determining Interfacial Adhesion Performance and Reliability for Microelectronics Applications Using a Wedge Test Method." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/30973.
Повний текст джерелаMaster of Science
Pour, Shahid Saeed Abadi Parisa. "Mechanical behavior of carbon nanotube forests under compressive loading." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47699.
Повний текст джерелаZheng, Jiantao. "Interfacial fracture of micro thin film interconnects under monotonic and cyclic loading." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26489.
Повний текст джерелаCommittee Chair: Sitaraman, Suresh; Committee Member: Degertekin, Levent; Committee Member: McDowell, David; Committee Member: Tummala, Rao; Committee Member: Vandentop, Gilroy; Committee Member: Wang, Zhong Lin. Part of the SMARTech Electronic Thesis and Dissertation Collection.