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Dissertations / Theses on the topic 'Cracks closure'

Author: Grafiati

Published: 4 June 2021

Last updated: 9 February 2022

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1

Alizadeh, Hassan. "Closure of three-dimensional fatigue cracks." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425128.

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2

Iyyer, Nagaraja S. "Closure of fatigue cracks at high strains." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/91124.

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Experiments were conducted on smooth specimens to study the closure behavior of short cracks at high cyclic strains under completely reversed cycling. Testing procedures and methodology, and closure measurement techniques, are described in detail. The strain levels chosen for the study cover from predominantly elastic to grossly plastic strains. Crack closure measurements were made at different crack lengths. The study reveals that, at high strains, cracks close only as the lowest stress level in the cycle is approached. The crack opening was observed to occur in the compressive part of the lo

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3

Iyyer, Nagaraja S. "Fatigue growth and closure of short cracks." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/52324.

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A study has been carried out to investigate the growth and closure behavior of short cracks in 2024-T351 aluminum alloy and four different conditions of 4340 steel using through thickness cracks of straight fronts. The experiments were carried out to study the influence of stress level, stress ratio, yield strength and prior austenitic grain A sizes in notched and unnotched specimens. The stereoimaging technique was developed and adapted to obtain crack closing and opening points, and also near tip displacement fields. Experimental results are presented with a general discussion. It was found

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4

Patel, Surendra Kumar. "Experimental And Numerical Studies On Fatigue Crack Growth Of Single And Interacting Multiple Surface Cracks." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/276.

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Design based on damage tolerance concepts has become mandatory in high technology structures. These concepts are also essential for evaluating life extension of aged structures which are in service beyond originally stipulated life. Fracture analysis of such structures in the presence of single or multiple three-dimensional flaws is essential for this approach. Surface cracks are the most commonly occurring flaws and development of accurate methods of analysis for such cracks is essential for structural integrity evaluation of newly designed or aged structures. The crack fronts of these surfac

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5

Rahman, Md Moshiur. "Experimental and theoretical study of the stress and strain fields around fatigue cracks and plasticity-induced crack closure." Thesis, Open University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.446310.

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6

Dahlin, Peter. "Growth of fatigue cracks subjected to non-proportional Mode I and II." Doctoral thesis, Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-585.

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7

Ignatiev, Konstantin I. "Development of x-ray phase contrast and microtomography methods for the 3D study of fatigue cracks." Diss., Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-08202004-114942/unrestricted/ignatiev%5Fkonstantin%5Fi%5F200407%5Fphd.pdf.

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Thesis (Ph. D.)--Materials science and engineering, Georgia Institute of Technology, 2005.<br>Stock, Stuart, Committee Chair ; Sanders, Thomas, Committee Member ; Snyder, Robert, Committee Member ; Johnson, Steven, Committee Member ; Wilkinson, Angus, Committee Member. Vita. Includes bibliographical references.

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8

Cadario, Alessandro. "Life prediction and mechanisms for the initiation and growth of short cracks under fretting fatigue loading." Doctoral thesis, KTH, Hållfasthetslära (Inst.), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4185.

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Fretting fatigue is a damage process that may arise in engineering applications where small cyclic relative displacements develop inside contacts leading to detrimental effects on the material fatigue properties. Fretting is located in regions not easily accessible, which makes it a dangerous phenomenon. It is therefore important to be able to make reliable predictions of the fretting fatigue lives. The work presented in this thesis has its focus on different aspects related to fretting fatigue in the titanium alloy Ti-17. A fretting experiment was developed which allowed for separate control

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9

Burgos, Diego Felipe Sarzosa. "Avaliação da vida à fadiga em materiais homogêneos e juntas soldadas incluindo efeitos de fechamento de trinca." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3135/tde-04062013-153636/.

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Esta tese investiga o efeito do fechamento de trinca sobre as previsões da vida à fadiga em materiais homogêneos e juntas soldadas. É apresentada uma metodologia para a simulação numérica do fenômeno de fechamento de trinca induzido por plasticidade utilizando o método dos elementos finitos. Ensaios laboratoriais de propagação de trinca por fadiga do aço ASTM A516 Gr. 70 à temperatura ambiente foram realizados usando corpos de prova típicos da mecânica da fratura nas condições soldada e homogênea. Estes resultados foram usados para validar a metodologia numérica do cálculo da carga de abertura

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10

CORBANI, SILVIA. "CRACK GROWTH WITH PARTIAL BENDING-INDUCED CRACK CLOSURE." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2012. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=23847@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO<br>CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO<br>Neste trabalho são investigadas experimentalmente e numericamente as mudanças de geometria em trincas inicialmente passantes submetidas a carregamento remoto de flexão pura induzindo fechamento parcial das faces da trinca. Esse crescimento de trinca pode ocorrer numa variedade de estruturas com defeitos pré-existentes, tais como fuselagens de aviões, cascos de navios, vasos de pressões e pontes metálicas. O carregamento de flexão pura ocasiona regiões de tração e compressão na

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11

Skinner, Jr Jeffrey David. "Finite Element Analysis of Plasticity-Induced Fatigue Crack Closure in Three-Dimensional Cracked Geometries." MSSTATE, 2001. http://sun.library.msstate.edu/ETD-db/theses/available/etd-05022001-123857/.

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Elastic-plastic finite element analyses were performed to predict the crack opening level profiles in semi-elliptical surface cracks. A script was written to use the commercial finite element code ANSYS to predict opening levels in cracked geometries. The functionality of the scripts was verified by comparing predicted opening levels in two and three-dimensional center-cracked geometries to experimental results. In addition, a parameter study was performed in which various aspects of the modeling routine were modified. This included a mesh refinement study as well as a study into the effect of

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12

Mirzaei, Majid. "On fatigue crack closure analysis and measurement." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=70339.

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This thesis describes a novel approach to the analysis of fatigue crack closure phenomena. Based on the proposed model, the combined effect of residual plastic stretch, asperity mismatch, and corrosion debris on the closure behavior of a fatigue crack can be simulated by a hypothetical rigid insert located in an ideal crack wake. Accordingly, the crack closing period can be modeled by a gradual contact between the ideal crack faces and the rigid insert.<br>The formulation of the model results in a set of equations which can predict the closure load as well as the load-CMOD characteristics usin

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13

De, Matos Paulo Fernando Pinto. "Plasticity induced fatigue crack closure: Modelling and Experiments." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491427.

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The understanding of fatigue crack closure has been proved to be a challenging and controversial topic among the fatigue community over the last three decades. Since the pioneering work of Elber, different forms of crack closure have been identified (e.g. roughness and oxide induced), however, plasticity-induced crack closure has been shown to be particularly relevant in engineering applications. The effect of the specimen (or component) thickness has been shown to have a significant effect on closure behaviour and this seems to be related to the relative size of the plastic zone. The state of

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14

Newman, John Andrew. "The Effects of Load Ratio on Threshold Fatigue Crack Growth of Aluminum Alloys." Diss., Virginia Tech, 2000. http://hdl.handle.net/10919/29418.

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The integrity of nearly all engineering structures are threatened by the presence of cracks. Structural failure occurs if a crack larger than a critical size exists. Although most well designed structures initially contain no critical cracks, subcritical cracks can grow to failure under fatigue loading, called fatigue crack growth (FCG). Because it is impossible or impractical to prevent subcritical crack growth in most applications, a damage tolerant design philosophy was developed for crack sensitive structures. Design engineers have taken advantage of the FCG threshold concept to design

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15

Wallhead, Ian. "Crack closure measurement by the optical method of caustics." Thesis, Open University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241083.

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16

Rehman, Atiq-Ur. "An investigation of methods of reducing fatigue crack growth by artificial crack-closure effects." Thesis, University of Salford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315379.

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17

McMaster, Fraser J. "The effects of load interaction on fatigue crack growth and crack closure in aluminium alloys." Thesis, University of Bristol, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297844.

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18

Loureiro-Homs, Jordi. "Modelling of TMF Crack Growth in Polycrystalline Gas Turbine Alloys : Accounting for Crack Closure Effects." Licentiate thesis, Linköpings universitet, Mekanik och hållfasthetslära, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-170275.

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The main objective of the work presented in this Licentiate of Engineering thesis is to investigate and model the fatigue crack propagation behaviour of the nickel-based superalloy Inconel 792, with special attention to the industrial lifing of high-temperature components. In-phase (IP) crack propagation tests have been performed at different temperatures and loading regimes, including extended hold times. The observations from these tests have been the basis for establishing several hypotheses to describe the crack growth behaviour, which progressively have been verified experimentally and nu

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19

Parry, M. R. "Finite element and analytical modelling of roughness induced fatigue crack closure." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342763.

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20

Whang, Kyunghyun. "Some problems of localized crack closure due to nearby concentrated loads /." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487326511712949.

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21

Lu, Yanwei. "Full-field modelling of crack tip shielding phenomena." Thesis, University of Plymouth, 2011. http://hdl.handle.net/10026.1/885.

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The application of fracture mechanics to engineering design has provided significant advances in understanding of the causes and mechanisms of failure and crack growth. Despite this, there are still some aspects that remain incompletely understood, such as the crack closure/crack shielding effect. The presence of crack closure/shielding acts to reduce . The mechanisms of crack closure/shielding are complicated, and have not been fully understood. This work focuses on the plasticity-induced crack tip shielding mechanism and presents a novel approach to characterise the elastic stress fields und

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22

Goulding, A. "Small fatigue crack growth in a near alpha titanium alloy : crack closure, stress gradient and temperature considerations." Thesis, Swansea University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.637082.

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The effect of fatigue crack closure in IMI 829 has been addressed for cracks growing from plain surfaces and under the influence of a stress concentration. Several test-piece configurations were employed, incuding thick and thin section double edge notches and standard corner crack (CC) geometries. All types incorporated an ultra fine corner slit to bias the crack initiation site. A thin double edge notch (DEN) specimen with a through section starter slit was also tested. Crack closure loads were measured using direct current potential drop (PD) and replica techniques. The primary closure mech

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23

Xu, Yigeng. "Closure assessment and overload transient behaviour in damage tolerant airframe materials." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390752.

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24

Kirmani, Ghulam Ashraf-Ul-Harmain. "Single overload fatigue crack growth retardation : an implementation of plasticity induced closure." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ32752.pdf.

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25

McKellar, Dougan Kelk. "A dislocation model of plasticity with particular application to fatigue crack closure." Thesis, University of Oxford, 2001. http://ora.ox.ac.uk/objects/uuid:45183b90-017f-4ac1-9550-94772a0ca88b.

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The ability to predict fatigue crack growth rates is essential in safety critical systems. The discovery of fatigue crack closure in 1970 caused a flourish of research in attempts to simulate this behaviour, which crucially affects crack growth rates. Historically, crack tip plasticity models have been based on one-dimensional rays of plasticity emanating from the crack tip, either co-linear with the crack (for the case of plane stress), or at a chosen angle in the plane of analysis (for plane strain). In this thesis, one such model for plane stress, developed to predict fatigue crack closure,

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26

Kemp, Ronald Martin John. "The effect of environment on fatigue and crack closure in aluminium alloys." Thesis, University of Southampton, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385101.

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27

Varvani, Farahani Ahmad. "Biaxial fatigue crack growth and crack closure under constant amplitude and periodic compressive overload histories in 1045 steel." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0010/NQ30656.pdf.

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28

Teall, Oliver. "Crack closure and enhanced autogenous healing of structural concrete using shape memory polymers." Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/100250/.

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Self-healing concrete has the potential to significantly reduce the life cycle cost of concrete structures. The ability for concrete to undergo autogenous self-healing is largely dependent upon the width of the cracks in the material. Shape memory polymers (SMP) can be used to close cracks in concrete and produce a compressive stress across crack faces, enhancing the load recovery associated with this healing process. Previous proof of concept studies used commercially available SMP strips to close cracks within small scale mortar beams. Within this thesis, specifically manufactured high shrin

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29

Baskaya, Mehmet. "Three-dimensional effects of crack closure in laminated composite plates subjected to bending loads." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA283342.

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30

Azeez, Ahmed. "High-Temperature Fatigue in a Steam Turbine Steel : Modelling of Cyclic Deformation and Crack Closure." Licentiate thesis, Linköpings universitet, Mekanik och hållfasthetslära, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-173354.

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Existing conventional thermal power plants are retrofitted for flexible operations to assist the transition toward more renewable energies. The deployment of many renewable energy power plants is necessary to achieve a clean environment with less pollution. However, the intermittent nature of renewable energies, due to weather changes, and the lack of efficient large energy storage systems put renewables at a disadvantage. Flexible operations of power plants imply fast and frequent start-ups. Thus, retrofitted power production plants can be utilised as an energy backup to satisfy the immediate

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31

Tuyishimire, Gabriel. "Utvärdering av osäkerhet i sprickfortplantningsmodeller." Thesis, Högskolan Väst, Avd för tillverkningsprocesser, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-8323.

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In aerospace industry and other major mechanical industry systems, engineering components that are subjected to cyclic loads often lead to progressive crack growth that eventually results in struc-tural fracture. The damage tolerance design which is based on the assumption of pre-existed flaws in a structure is an important approach in aircraft industry since it is impossible to have flaw-free manufactured components.In this thesis work, an evaluation of crack propagation models was carried out. Fatigue crack growth threshold and fatigue crack growth rate models were evaluated. A method to pre

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32

Solanki, Kiran N. "TWO AND THREE-DIMENSIONAL FINITE ELEMENT ANALYSIS OF PLASTICITY-INDUCED FATIGUE CRACK CLOSURE ? A COMPREHENSIVE PARAMETRIC STUDY." MSSTATE, 2002. http://sun.library.msstate.edu/ETD-db/theses/available/etd-11102002-143748/.

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Finite element analyses are frequently used to model growing fatigue cracks and the associated plasticity-induced crack closure. Two-dimensional, elastic-perfectly plastic finite element analyses of middle-crack tension (M(T)), bend (SEB), and compact tension (C(T)) geometries were conducted to study fatigue crack closure and to calculate the crack opening values under plane-strain and plane-stress conditions. The loading was selected to give the same maximum stress intensity factor in both geometries, and thus similar initial forward plastic zone sizes. Mesh refinement studies were performed

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33

Wu, Weidong Aerospace &amp Mechanical Engineering Australian Defence Force Academy UNSW. "Fatigue crack propagation behaviour of welded and weld repaired 5083 aluminium alloy joints." Awarded by:University of New South Wales - Australian Defence Force Academy. School of Aerospace and Mechanical Engineering, 2002. http://handle.unsw.edu.au/1959.4/38663.

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Welding, as one of the most effective joining methods for metals, has been extensively applied in engineering usage for a long time. When cracks occur in the vicinity of weldments, weld repairs are frequently considered for crack repair to extend service life. In order to evaluate to what extent the weld repair has improved the fatigue life of a cracked welded structure, it is necessary to be able to determine the residual life of the cracked welded joint, as well as the life of the weld repaired joint. Both these assessments require that the fatigue crack growth data be available. The determ

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34

Dharmawan, Ferry, and ferry dharmawan@rmit edu au. "The Structural Integrity And Damage Tolerance Of Composite T-Joints in Naval Vessels." RMIT University. Aerospace, Mechanical and Manufacturing Engineering, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20081216.163144.

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In this thesis, the application of composite materials for marine structures and specifically naval vessels has been explored by investigating its damage criticality. The use of composite materials for Mine Counter Measure Vessels (MCMVs) was desirable, especially for producing material characteristics, such as light weight, corrosion resistance, design flexibility due to its anisotropic nature and most importantly stealth capability. The T-Joint structure, as the primary connection between the hull and bulkhead forms the focus of this research. The aim of the research was to determine the met

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35

Morano, Robert Natale. "Effect of R-ratio on crack closure in Al-Li 2090 T8E41, investigated non-destructively with x-ray microtomography." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/19903.

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36

Šebík, Marek. "Vliv plasticky indukovaného zavírání únavové trhliny na její šíření." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-382564.

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This study is focused on plasticity induced crack closure effect on fatigue crack propagation. It utilizes finite element method modeling to evaluate the effect of this phenomenon on crack propagation at a series of MT specimen configurations. The modeling has been done both 2D and 3D. Comparison of computed results with experiments explains effect of the phenomenon at performed experimental measurements. Above all, three-dimensional modeling provides assessment of plasticity induced crack closure through thickness of the object. Thereby it explains shapes of fatigue crack fronts and lays foun

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37

Mohin, Ma. "Fatigue crack growth assessment and fatigue resistance enhancement of aluminium alloys." Thesis, University of Hertfordshire, 2018. http://hdl.handle.net/2299/20824.

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Fatigue damage of aluminium alloys is one of the key concerns in transport industries, particularly in the aerospace industry. The purpose of the project is to develop new knowledge and techniques against fatigue failure for these industries through a systematic investigation of fatigue resistance and crack growth behaviours of aluminium alloys. Fatigue and fracture mechanics have been investigated analytically, numerically and experimentally in this project. Overload transient effect on fatigue crack growth has been examined by considering various parameters including crack closure, overload

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38

Orifici, Adrian Cirino, and adrian orifici@student rmit edu au. "Degradation Models for the Collapse Analysis of Composite Aerospace Structures." RMIT University. Aerospace, Mechanical and Manufacturing Engineering, 2007. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20080619.090039.

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39

Silversides, Ian. "Détection de l'initiation de la délamination des matériaux composites par suivi de l'émission acoustique." Mémoire, Université de Sherbrooke, 2012. http://hdl.handle.net/11143/6210.

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Cette étude, basée sur la surveillance des ondes d'émission acoustique (E.A.), présente le développement d'une approche de prédiction de l'initiation de la délamination de pièces composites soumises à des chargements statiques et en fatigue. La surveillance des ondes d'E.A. fait parti d'un nombre restreint de méthodes pouvant détecter, en continu, l'apparition et la croissance de dommages dans les matériaux composites. L'approche est comparée à des méthodes conventionnelles ainsi qu'à une modélisation numérique pour des composites à fibre de carbone unidirectionnels et tissés, sur une gamme de

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40

Chrétien, Gaëlle. "Etude de la propagation de fissures physiquement courtes dans les alliages de titane pour turbomachines d'hélicoptères à différentes températures." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2017. http://www.theses.fr/2017ESMA0022.

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Cette thèse s’inscrit dans le cadre général de l’étude de la tolérance au dommage des pièces tournantes dans les turbomachines d’hélicoptères et porte sur la résistance à la propagation de fissures courtes 2D.Pour mener à bien cette étude, l’effet de la température est d’abord étudié sur les seuils de propagation de fissures longues à R=0,1 sur deux alliages TA6V et Ti6242 de microstructure bimodale (20°C et 400°C pour le TA6V et 20°C, 200°C et 500°C pour le Ti6242). Au voisinage du seuil, le comportement effectif(après correction de la fermeture) est sensiblement identique pour les deux allia

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41

Lados, Diana Aida. "Fatigue crack growth mechanisms in Al-Si-Mg alloys." Link to electronic thesis, 2004. http://www.wpi.edu/Pubs/ETD/Available/etd-0204104-125758.

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Thesis (Ph. D.)--Worcester Polytechnic Institute.<br>Keywords: Microstructure; Elastic-Plastic Fracture Mechanics; Crack closure; A356; J-integral; Conventionally cast and SSM Al-Si-Mg alloys; Residual stress; Heat treatment; Fatigue crack growth mechanisms; Threshold stress intensity factor; Plastic zone; Paris law; Fracture toughness; Roughness. Includes bibliographical references.

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42

Ucak, Ibrahim. "Assessment Of Different Finite Elementmodeling Techniques On Delamination Growth Inadvanced Composite Structures." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614188/index.pdf.

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Virtual crack closure technique (VCCT) is commonly used to analyze debonding/delamination onset and growth in fiber reinforced composite assemblies. VCCT is a computational fracture mechanics based approach, and is based on Irwin&rsquo<br>s crack closure integral. In this study, the debonding/delamination onset and growth potential in a bonded fiber reinforced composite skin-flange assembly is investigated using the VCCT. A parametric finite element analyses is conducted. The finite element analyses results are compared with coupon level experimental results available in the literature. The e

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43

Gates, Nicholas R. "Fatigue Behavior under Multiaxial Stress States Including Notch Effects and Variable Amplitude Loading." University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1469637495.

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44

Taleb, Wissam. "Influence de l'historique du chargement sur la fermeture induite par la plasticité et la forme d'une fissure de fatigue." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2021. http://www.theses.fr/2021ESMA0003.

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L'objectif de cette étude est de fournir un outil numérique prédictif tridimensionnel de l'évolution de la courbure du front de fissure lors de la propagation d'une fissure de fatigue en tenant compte de la fermeture de fissure induite par la plasticité. Des tests ciblés effectués sur une éprouvette CT-50 d'acier inoxydable austénitique 304L ont donné la forme stabilisée du front de fissure pour une fissure longue pour différents rapports de charge R et différentes amplitudes ΔK du facteur d'intensité de contrainte (FIC). Afin d'éviter toute influence de l'historique de chargement, une valeur

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45

Santos, Neilor Cesar dos. "Análise de problemas de trincas em materiais anisotrópicos usando o método dos elementos finitos: abordagem pela integral Jk." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/18/18135/tde-16022016-115310/.

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Apresenta-se um estudo, por meio do método dos elementos finitos, de problemas quase-estáticos de trincas em materiais anisotrópicos. Os fatores de intensidade de tensão em modo misto de carregamento foram determinados utilizando-se as metodologias da integral Jk, da correlação dos deslocamentos e da integral de fechamento de trinca modificada. Para a integral Jk, foi desenvolvida uma formulação baseada nas leis da conservação da elasto-estática e das integrais independentes do percurso. Na expressão, para a integral J2 levou-se em consideração o termo não singular da representação analítica d

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Mattrand, Cécile. "Approche probabiliste de la tolérance aux dommages." Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2011. http://tel.archives-ouvertes.fr/tel-00738947.

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En raison de la gravité des accidents liés au phénomène de fatigue-propagation de fissure, les préoccupations de l'industrie aéronautique à assurer l'intégrité des structures soumises à ce mode de sollicitation revêtent un caractère tout à fait essentiel. Les travaux de thèse présentés dans ce mémoire visent à appréhender le problème de sûreté des structures aéronautiques dimensionnées en tolérance aux dommages sous l'angle probabiliste. La formulation et l'application d'une approche fiabiliste menant à des processus de conception et de maintenance fiables des structures aéronautiques en conte

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Teall, O. R., M. Pilegis, John Sweeney, et al. "Development of high shrinkage Polyethylene Terephthalate (PET) shape memory polymer tendons for concrete crack closure." 2017. http://hdl.handle.net/10454/11340.

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Yes<br>The shrinkage force exerted by restrained shape memory polymers can potentially be used to close cracks in structural concrete. This paper describes the physical processing and experimental work undertaken to develop high shrinkage die-drawn Polyethylene Terephthalate (PET) shape memory polymer tendons for use within a crack closure system. The extrusion and die-drawing procedure used to manufacture a series of PET tendon samples is described. The results from a set of restrained shrinkage tests, undertaken at differing activation temperatures, are also presented along with the me

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Venkatesha, K. S. "Finite Element Estimates Of Strain Energy Release Rate Components At Interface Cracks." Thesis, 1995. http://etd.iisc.ernet.in/handle/2005/1860.

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Muthukumar, R. "Effect Of Material Non-Linearity Of Adherends On Fracture Behaviour Of Bimaterial Interface Cracks." Thesis, 2005. http://etd.iisc.ernet.in/handle/2005/1470.

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Okayasu, Mitsuhiro. "Experimental study of crack closure characteristics /." 2006. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=442642&T=F.

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