Relevant bibliographies by topics / Crack propagation / Dissertations / Theses

Dissertations / Theses on the topic 'Crack propagation'

To see the other types of publications on this topic, follow the link: Crack propagation.
Author: Grafiati
Published: 4 June 2021
Last updated: 20 July 2024

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 dissertations / theses for your research on the topic 'Crack propagation.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.

1

Hodgkins, Andrew D. "Crack propagation in nuclear graphite." Thesis, University of Manchester, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.488486.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Dumpleton, P. "Fatigue crack propagation in polyethylene." Thesis, Cranfield University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373987.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Hejman, Ulf. "On initiation of chemically assisted crack growth and crack propagation paths of branching cracks in polycarbonate." Licentiate thesis, Malmö högskola, Teknik och samhälle, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-7790.

Full text
Abstract:
Stress corrosion, SC, in some cases gives rise to stress corrosion cracking, SCC, which differs from purely stress intensity driven cracks in many aspects. They initiate and grow under the influence of an aggressive environment in a stressed substrate. They grow at low load and may branch. The phenomenon of SCC is very complex, both the initiation phase and crack extension itself of SCC is seemingly associated with arbitrariness due to the many unknown factors controlling the process. Such factors could be concentration of species in the environment, stress, stress concentration, electrical conditions, mass transport, and so on.In the present thesis, chemically assisted crack initiation and growth is studied with special focus on the initiation and branching of cracks. Polycarbonate plates are used as substrates subjected to an acetone environment. Experimental procedures for examining initiation and branching in polycarbonate are presented. An optical microscope is employed to study the substrate.The attack at initiation is quantified from pits found on the surface, and pits that act as origin for cracks is identified and the distribution is analysed. A growth criterion for surface cracks is formulated from the observations, and it is used to numerically simulate crack growth. The cracks are seen to coalesce, and this phenomenon is studied in detail. Branching sites of cracks growing in the bulk of polycarbonate are inspected at the sample surface. It is found that the total width of the crack branches are approximately the same as the width of the original crack. Also, angles of the branches are studied. Further, for comparison the crack growth in the bulk is simulated using a moving boundary problem based algorithm and similar behaviour of crack branching is found.
APA, Harvard, Vancouver, ISO, and other styles
4

Leaity, Grant Philip. "Residual stresses and fatigue crack propagation." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293635.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Viesca, Lobaton Gabriel D. "Fatigue crack propagation in plastic fields." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301842.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

胡思來 and See-loi Wu. "Numerical analysis of dynamic crack propagation." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1988. http://hub.hku.hk/bib/B31208459.

Full text
APA, Harvard, Vancouver, ISO, and other styles
7

Abdul-Salam, Ezzet Hameed. "Fatigue crack propagation in mild steel." Thesis, University of Salford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.291749.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Al-Falou, Ahmed Amir. "A theoretical analysis of crack propagation." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624858.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Hafezi, M. H., R. Alebrahim, and T. Kundu. "Crack propagation modeling using Peridynamic theory." SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622515.

Full text
Abstract:
Crack propagation and branching are modeled using nonlocal peridynamic theory. One major advantage of this nonlocal theory based analysis tool is the unifying approach towards material behavior modeling- irrespective of whether the crack is formed in the material or not. No separate damage law is needed for crack initiation and propagation. This theory overcomes the weaknesses of existing continuum mechanics based numerical tools (e.g. FEM, XFEM etc.) for identifying fracture modes and does not require any simplifying assumptions. Cracks grow autonomously and not necessarily along a prescribed path. However, in some special situations such as in case of ductile fracture, the damage evolution and failure depend on parameters characterizing the local stress state instead of peridynamic damage modeling technique developed for brittle fracture. For brittle fracture modeling the bond is simply broken when the failure criterion is satisfied. This simulation helps us to design more reliable modeling tool for crack propagation and branching in both brittle and ductile materials. Peridynamic analysis has been found to be very demanding computationally, particularly for real-world structures (e.g. vehicles, aircrafts, etc.). It also requires a very expensive visualization process. The goal of this paper is to bring awareness to researchers the impact of this cutting-edge simulation tool for a better understanding of the cracked material response. A computer code has been developed to implement the peridynamic theory based modeling tool for two-dimensional analysis. A good agreement between our predictions and previously published results is observed. Some interesting new results that have not been reported earlier by others are also obtained and presented in this paper. The final objective of this investigation is to increase the mechanics knowledge of self-similar and self-affine cracks.
APA, Harvard, Vancouver, ISO, and other styles
10

Wu, See-loi. "Numerical analysis of dynamic crack propagation /." [Hong Kong] : University of Hong Kong, 1988. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12354569.

Full text
APA, Harvard, Vancouver, ISO, and other styles
11

Perng, Jia-Der. "Analysis of crack propagation in asphalt concrete using a cohesive crack model." Connect to this title online, 1989. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1094737677.

Full text
APA, Harvard, Vancouver, ISO, and other styles
12

Brunelli and Marco Claudio Pio. "Crack propagation in quasicrystals at different temperatures." Phd thesis, Universitaet Stuttgart, 2000. http://elib.uni-stuttgart.de/opus/volltexte/2001/798/index.html.

Full text
APA, Harvard, Vancouver, ISO, and other styles
13

Sharifimajd, Babak. "High temperature fatigue crack propagation in Inconel718." Thesis, Linköping University, Solid Mechanics, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-57854.

Full text
APA, Harvard, Vancouver, ISO, and other styles
14

Yayla, Pasa. "Rapid crack propagation in polyethylene gas pipes." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/8711.

Full text
APA, Harvard, Vancouver, ISO, and other styles
15

Meyer, Arnd, Frank Rabold, and Matthias Scherzer. "Efficient finite element simulation of crack propagation." Universitätsbibliothek Chemnitz, 2006. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200601402.

Full text
Abstract:
The preprint delivers an efficient solution technique for the numerical simulation of crack propagation of 2D linear elastic formulations based on finite elements together with the conjugate gradient method in order to solve the corresponding linear equation systems. The developed iterative numerical approach using hierarchical preconditioners comprehends the interesting feature that the hierarchical data structure will not be destroyed during crack propagation. Thus, one gets the possibility to simulate crack advance in a very effective numerical manner including adaptive mesh refinement and mesh coarsening. Test examples are presented to illustrate the efficiency of the given approach. Numerical simulations of crack propagation are compared with experimental data.
APA, Harvard, Vancouver, ISO, and other styles
16

Tilbrook, Matthew Thomas Materials Science &amp Engineering Faculty of Science UNSW. "Fatigue crack propagation in functionally graded materials." Awarded by:University of New South Wales. Materials Science & Engineering, 2005. http://handle.unsw.edu.au/1959.4/21885.

Full text
Abstract:
Propagation of cracks in functionally graded materials (FGMs) under cyclic loading was investigated via experiments and finite element (FE) analysis. Alumina-epoxy composites with an interpenetrating-network structure and tailored spatial variation in composition were produced via a multi-step infiltration technique. Compressed polyurethane foam was infiltrated with alumina slip. After foam burn-out and sintering, epoxy was infiltrated into the porous alumina body. Non-graded specimens with a range of compositions were produced, and elastic properties and fatigue behaviour were characterised. An increase in crack propagation resistance under cyclic loading was quantified via a novel analytical approach. A simulation platform was developed with the commercial FE package ANSYS. Material gradient was applied via nodal temperature definitions. Stress intensity factors were calculated from nodal displacements near the crack-tip. Deflection criteria were compared and the local symmetry criterion provided the most accurate and efficient predictions. An automated mesh-redefinition algorithm enabled incremental simulation of crack propagation. Effects of gradient and crack-geometry parameters on crack-tip stresses were investigated, along with influences of crack-shape, crack-bridging, residual stresses and plasticity. The model provided predictions and data analysis for experimental specimens. Fatigue cracks in graded specimens deflected due to elastic property mismatch, concordant with FE predictions. In other FGMs, thermal or plastic properties may dominate deflection behaviour. Weaker step-interfaces influenced crack paths in some specimens; otherwise effects of toughness variation and gradient steps on crack path were negligible. Crack shape has an influence, but this is secondary to that of elastic gradient. Cracks in FGM specimens initially experienced increase in fatigue resistance with crack-extension followed by sudden decreases at step-interfaces. Bridging had a notable effect on crack propagation resistance but not on crack path. Similarly, crack paths did not differ between monotonic and cyclic loading, although crack-extension effects did. Recommendations for analysis and optimisation strategies for other FGM systems are given. Experimental characterization of FGMs is important, rather than relying on theoretical models. Opportunities for optimization of graded structures are limited by the properties of the constituent materials and resultant general crack deflection behaviour.
APA, Harvard, Vancouver, ISO, and other styles
17

Yiangou, Savvakis Chrysostomou. "Fatigue crack propagation in low density polyethylene." Thesis, Imperial College London, 1988. http://hdl.handle.net/10044/1/47317.

Full text
APA, Harvard, Vancouver, ISO, and other styles
18

Hauber, Brett Kenneth. "Fatigue Crack Propagation in Functionally Graded Materials." University of Dayton / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1259881312.

Full text
APA, Harvard, Vancouver, ISO, and other styles
19

Brunelli, Marco Claudio Pio. "Crack propagation in quasicrystals at different temperatures." [S.l. : s.n.], 2001. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB9075745.

Full text
APA, Harvard, Vancouver, ISO, and other styles
20

Rudhart, Christoph Paul. "Crack propagation in decagonal and icosahedral quasicrystals." [S.l. : s.n.], 2004. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11078364.

Full text
APA, Harvard, Vancouver, ISO, and other styles
21

Baer, Máren Ingá. "Crack propagation calculations in non-elastic metals." Thesis, Luleå tekniska universitet, Material- och solidmekanik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-71108.

Full text
Abstract:
It is important to know the lifespan of a component, thus services can be planed. At Siemens Industrial Turbomachinery AB (SIT AB) develop and produce gas and steam turbines, the turbines are heavily strained by thermal and centrifugal forces during their life span which lead to cracking. Today there is no good crack propagation method for materials with large amount of plastic deformation and creep. At SIT a new method, ΔKBDCPP, has been developed that takes these phenomenon in consideration. It is assumed that the whole model has plastic material properties except circular elements at the crack front which have elastic properties. The new method is reviewed by doing simulations on a a specimen model in Franc3D together with the FE program Abaqus. There have been conducted thermo-mechanical fatigue (TMF) tests and 2D simulations on specimen to measure the crack propagation. The TMF tests where immitaded in new simulations with the method ΔKBDCPP. Forces, creep times, cycles and material data where emulated in the model and then simulated. The number of cycles per crack length for the isothermal simulations became higher then for the TMF tests. This is a expected result because the conditions are optimal during simulations, which they may not be during experimental test. The result of ΔKBDCPP are closer to the TMF test results then the 2D simulated ΔKeffective, another crack propagation calculation method. Additionally, out-of-phase (OP) simulations where carried out, in OP the maximum temperature and maximum stress do not coincide. When the temperature is at max the component is held in the minimum stress. For OP simulations the results became irregular, for one of the simulations the number of cycles per crack length became lower for the simulated specimen than for the TMF test, and contrariwise for the other OP simulation. However, it was concluded that the later was correct because the majority of the simulations, and all the isothermal simulations, gave this result. it also was the result for the isothermal simulations. One OP simulation was compared to a 2D simulation and here the method of ΔKBDCPP was also more accurate to the TMF tests. The method of ΔKBDCPP seem to function well however, the solving time for models with creep is long. A model with a small crack and creep is time consuming to simulate, which is a disadvantages.
Det är viktigt att veta livslängden på en komponent, då kan det planeras för en service. På Siemens Industrial Turbomachinery AB (SIT AB) utvecklas och produceras det gas- och ångturbiner, turbiner utsätts för höga temperaturer och krafter under dess livstid vilket resulterar i sprickor. Idag finns det inte en bra sprickpropageringsteori för material i ett stort plasticerat tillstånd och kryp, SIT har därför tagit fram en ny metod som ska ta hänsyn till dessa parametrar. I den nya beräkningsmetoden, ΔKBDCPP, antas det att hela modellen har en plastisk materialmodell förutom ett antal ringelement vid sprickspetsen som antas ha en elastisk materialmodell. Den nya metoden undersöks genom att provstavsmodell simuleras i programmet Franc3D tillsammans med Abaqus. Det har tidigare gjorts termodynamiska utmattningsprov (TMF), samt simuleringar i 2D, på provstavar för att mäta sprickpropageringen. Därför imiterades dessa TMF prov i nya simuleringar med metoden för ΔKBDCPP. Krafter, hålltider, cykler och materialdata efterliknades i modellen och sedan kördes simuleringarna. För de isoterma körningarna blev resultatet att antalet cykler per spricklängd är högre för simulerade värden än för TMF prover, vilket var väntat. Vid simulationer är det optimala förhållanden utan avvikelser, vilket kan finnas vid experimentella tester. De simulerade värdena för ΔKBDCPP stämmer bättre överens med TMF proverna än de 2D simulerade resultaten för ΔKeffective, en annan beräkningsmodell för sprickpropagering. Även out-of-phase (OP) simuleringar genomfördes, vid OP sker inte temperatur max och spännings max samtidigt. När det är max temperatur hålls komponenten i den minimala spänningen. För OP simuleringarna blev resultatet annorlunda, ena körningen blev antalet cykler per spricklängd lägre för de simulerade värden än för TMF prover och i den andra blev det tvärt om. Dock drogs slutsatsen att den senare stämde då majoriteten av körningarna, och alla isoterma körningar, gav det resultatet. En OP körning jämfördes med en 2D körning och även där var metoden för ΔKBDCPP närmare TMF provsresultatet. ΔKBDCPP metoden verkar fungera bra, dock är simuleringstiden för att lösa körningar med kryp väldigt lång. En modell med en liten spricka och kryp är mycket tidskrävande att lösa, vilket är en nackdel.
APA, Harvard, Vancouver, ISO, and other styles
22

Sewell, Anthony J. "Crack propagation in high modulus asphalt mixtures." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/43552/.

Full text
Abstract:
This Thesis was undertaken at the University of Nottingham which has a world class history of research into the fatigue of asphalt materials. The work described in this thesis was part of a research project funded by EPSRC, which attempts to gain a greater understanding of fatigue crack propagation in High Modulus Base (HMB) materials. Following on from Pell, Brown and Read this research has introduced the Compact Tension (CT) Test and Fracture Mechanics principles to examine the behaviour of HMB materials which had relatively little fatigue behavioural understanding on commencement of this research. This research investigated the fatigue cracking behaviour of twelve High Modulus Base (HMB) binders and mixtures. The research was instigated in response to the introduction of these HMB binders from France, as it was thought that these materials were not particularly well understood. In hindsight, this view was proven to be correct, as numerous problems have been experienced after using such materials. The Compact Tension test has been proved to be an effective means of testing bituminous mixtures for their crack propagation resistance, allowing the study of temperature effects. Crack propagation is dramatically affected by both binder hardness and temperature. In a pavement, the current approach to design, assuming a single fatigue characteristic, underestimates the life of 35 and 25 pen mixtures. However, it probably overestimates the life of 15 pen mixtures by not accounting for the effects of low temperatures.
APA, Harvard, Vancouver, ISO, and other styles
23

Molinari, Gianluca <1979&gt. "Fatigue Crack Propagation in Pressurized metallic Fuselages." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5849/1/Tesi_Molinari.pdf.

Full text
Abstract:
On the basis of well-known literature, an analytical tool named LEAF (Linear Elastic Analysis of Fracture) was developed to predict the Damage Tolerance (DT) proprieties of aeronautical stiffened panels. The tool is based on the linear elastic fracture mechanics and the displacement compatibility method. By means of LEAF, an extensive parametric analysis of stiffened panels, representative of typical aeronautical constructions, was performed to provide meaningful design guidelines. The effects of riveted, integral and adhesively bonded stringers on the fatigue crack propagation performances of stiffened panels were investigated, as well as the crack retarder contribution using metallic straps (named doublers) bonded in the middle of the stringers bays. The effect of both perfectly bonded and partially debonded doublers was investigated as well. Adhesively bonded stiffeners showed the best DT properties in comparison with riveted and integral ones. A great reduction of the skin crack growth propagation rate can be achieved with the adoption of additional doublers bonded between the stringers.
APA, Harvard, Vancouver, ISO, and other styles
24

Molinari, Gianluca <1979&gt. "Fatigue Crack Propagation in Pressurized metallic Fuselages." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amsdottorato.unibo.it/5849/.

Full text
Abstract:
On the basis of well-known literature, an analytical tool named LEAF (Linear Elastic Analysis of Fracture) was developed to predict the Damage Tolerance (DT) proprieties of aeronautical stiffened panels. The tool is based on the linear elastic fracture mechanics and the displacement compatibility method. By means of LEAF, an extensive parametric analysis of stiffened panels, representative of typical aeronautical constructions, was performed to provide meaningful design guidelines. The effects of riveted, integral and adhesively bonded stringers on the fatigue crack propagation performances of stiffened panels were investigated, as well as the crack retarder contribution using metallic straps (named doublers) bonded in the middle of the stringers bays. The effect of both perfectly bonded and partially debonded doublers was investigated as well. Adhesively bonded stiffeners showed the best DT properties in comparison with riveted and integral ones. A great reduction of the skin crack growth propagation rate can be achieved with the adoption of additional doublers bonded between the stringers.
APA, Harvard, Vancouver, ISO, and other styles
25

Donohoe, C. J. "Corrosion fatigue of a high strength low alloy steel." Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322985.

Full text
APA, Harvard, Vancouver, ISO, and other styles
26

Burman, Magnus. "Fatigue crack initiation and propagation in sandwich structures." Doctoral thesis, KTH, Flygteknik, 1998. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2696.

Full text
Abstract:
The focus throughout this thesis is on the fatigue characteristics of core materials used insandwich structures. Three sandwich configurations are investigated, two with cellular foamsand one with honeycomb core material These corresponds to typical materials and dimensionsused in the marine and aeronautical industry.A modified four-point bending rig, which enables reversed loading, is successfully used forconstant amplitude fatigue tests of all material configurations. The core materials are tested asused in composite sandwich beams and through the design of the specimens the desiredfailure is in shear of the core. Analyses and inspections during and after the tests supports thetheory that the fracture initiation and fatigue failure occurs in a large zone of the core withwell distributed micro cracks rather than a single propagating crack. The fatigue test resultsare plotted in stress life diagrams including a Weibull type function which provides a goodaccuracy curve fit to the results. The fatigue life of the core materials is found to be reducedwith a increased load ratio, R.The influence on the strength and fatigue performance on sandwich beams with two types ofcore damages, an interfacial disbond and a flawed butt-joint, are experimentally investigated.The fatigue failure initiates at the stress intensity locations which are present due to the predamage.The specimens with flawed butt-joints display a fatigue crack propagation in theinterface between the core and face of the sandwich while the crack propagates through thethickness of the beams where an initial interface flaw is present. A fatigue failure predictionmodel is suggested which utilises the fatigue performance of undamaged beams and thestrength reduction due to the damages. The approach is correlated with results from fatiguetesting and satisfactory correlation is found.A uni-axial fatigue tests method is developed which simplifies the rig and specimenscompared to the four point bend method. A comparison between the results from uni-axialtension/compression fatigue tests and shear fatigue tests shows good correlation, although theR-dependency differs in some cases.The fatigue crack propagation rates are investigated for two configurations: crackspropagating in pure foam core material and cracks propagating in the core material near andalong a sandwich face/core interface. The rate at which a crack propagates stable in the socalled Paris’ regime is extracted for both Mode I and Mode II loading. The agreement betweenthe Mode I crack propagation rate in the pure foam and in the core/face sandwich interfacelayer supports the theory that the crack actually propagates in the sandwich core beneath astiffened resin rich layer present in the face/core interface. The stress intensity thresholds andthe limits at which the crack growth becomes unstable are further established.Acoustic Emission (AE) is used to monitor crack initiation and growth in the core, duringboth static and fatigue loading. It is found that the approximate location of AE-hits can bedetermined which demonstrates that AE has a potential both as an non destructive testing tooland to study the failure process of non-visible sub-surface damages in sandwich structures.
QC 20100520
APA, Harvard, Vancouver, ISO, and other styles
27

Ivankovic, Alojz. "Rapid crack propagation in polymer multi-layer systems." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/46837.

Full text
APA, Harvard, Vancouver, ISO, and other styles
28

Guirgis, Sameh. "Fatigue crack propagation in steel components at resonance." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ62216.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
29

Crepeau, Paul Noles. "Crack propagation in high chromium white cast iron." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/11182.

Full text
APA, Harvard, Vancouver, ISO, and other styles
30

馮錦生 and Kam-sang Fung. "Fatigue crack propagation with strain energy density approach." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1989. http://hub.hku.hk/bib/B31209713.

Full text
APA, Harvard, Vancouver, ISO, and other styles
31

Yang, Jing. "Fatigue crack propagation threshold in lamellar TiAl alloys." Thesis, University of Birmingham, 2015. http://etheses.bham.ac.uk//id/eprint/5620/.

Full text
Abstract:
In the present study, the effect of lamellar spacing, volume fraction of equiaxed gamma grains and lamellar orientation on fatigue crack propagation threshold have been assessed for three as-cast γ-TiAl alloys, Ti45Al2Mn2Nb1B (4522XD), Ti45Al2Mn2Nb (4522) and Ti46Al8Nb (at %). The influence of alloying elements, Nb and Ta on fatigue threshold was also studied with five forged alloys, Ti45Al2Mn2Nb1B, Ti45Al2Nb2Ta1B, Ti45Al2Mn2Ta1B, Ti45Al2Mn4Ta1B and Ti45Al2Mn4Nb1B. The fatigue crack propagation threshold tests were carried out at 650°C in air at a stress ratio R=0.1 and frequency of 10HZ. In addition, the microstructural characterisation of fatigue crack growth fracture surface was also examined by SEM. The samples assessed for fatigue crack propagation threshold failed mainly by translamellar fracture and interlamellar fracture. Interlamellar cracking occurs in lamellar colonies at any lamellar orientation at high stress intensity factor, ΔK, while at low ΔK cracking occurs in lamellar colonies only when the lamellar interface is parallel to the fracture plane. Therefore, the fracture behaviour is determined by both lamellar orientation and ΔK. The fatigue crack propagation threshold shows little sensitivity to lamellar spacing and volume fraction of equiaxed gamma grains with 4522XD variants in the studied range.
APA, Harvard, Vancouver, ISO, and other styles
32

Behera, Santosh K. "Molecular Dynamics Simulation of Crack Propagation in Nickel." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1285010270.

Full text
APA, Harvard, Vancouver, ISO, and other styles
33

Lee, Sam Lai. "A decohesion model of hydrogen assisted crack propagation /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487322984316684.

Full text
APA, Harvard, Vancouver, ISO, and other styles
34

Palettas, Panickos Neophytos. "Stochastic modeling and predictions for fatigue crack propagation /." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487597424135962.

Full text
APA, Harvard, Vancouver, ISO, and other styles
35

VINOGRADOV, Alexei. "Fatigue Crack Propagation in Copper Single and Bicrystals." Kyoto University, 1997. http://hdl.handle.net/2433/202336.

Full text
APA, Harvard, Vancouver, ISO, and other styles
36

Fung, Kam-sang. "Fatigue crack propagation with strain energy density approach /." [Hong Kong] : University of Hong Kong, 1989. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12827204.

Full text
APA, Harvard, Vancouver, ISO, and other styles
37

Gualandi, Gabriele. "Crack modeling and crack propagation in structures using damage model and extended finite element techniques." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/3931/.

Full text
APA, Harvard, Vancouver, ISO, and other styles
38

Gustafsson, David. "High temperature fatigue crack propagation behaviour of Inconel 718." Doctoral thesis, Linköpings universitet, Hållfasthetslära, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-85934.

Full text
Abstract:
The overall objective of this work has been to develop and evaluate tools for designing against fatigue in gas turbine applications, with special focus on the nickel-based superalloy Inconel 718. The fatigue crack propagation behaviour under high temperature hold times has been studied. Firstly, the main fatigue crack propagation phenomena have been investigated with the aim of setting up a basis for fatigue crack propagation modelling. Secondly, modelling of the observed behaviour has been performed. Finally, the constitutive behaviour of the material has been studied, where focus has been placed on trying to describe the mean stress relaxation and initial softening of the material under intermediate temperatures. This thesis is divided into two parts. The first part describes the general framework, including basic observed fatigue crack propagation behaviour of the material when subjected to hold times at high temperature as well as a background for the constitutive modelling of mean stress relaxation. This framework is then used in the second part, which consists of the seven included papers.
APA, Harvard, Vancouver, ISO, and other styles
39

Gustafsson, David. "Constitutive and fatigue crack propagation behaviour of Inconel 718." Licentiate thesis, Linköpings universitet, Hållfasthetslära, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-72610.

Full text
Abstract:
In this licentiate thesis the work done in the TURBO POWER project Influence of high temperature hold times on the fatigue life of nickel-based superalloys will be presented. The overall objective of this project is to develop and evaluate tools for designing against fatigue in gas turbine applications, with special focus on the nickel-based superalloy Inconel 718. Firstly, the constitutive behaviour of the material has been been studied, where focus has been placed on trying to describe the mean stress relaxation and initial softening of the material under intermediate temperatures. Secondly, the fatigue crack propagation behaviour under high temperature hold times has been studied. Focus has here been placed on investigating the main fatigue crack propagation phenomena with the aim of setting up a basis for fatigue crack propagation modelling. This thesis is divided into two parts. The first part describes the general framework, including basic constitutive and fatigue crack propagation behaviour as well as a theoretical background for the constitutive modelling of mean stress relaxation. This framework is then used in the second part, which consists of the four included papers.
APA, Harvard, Vancouver, ISO, and other styles
40

Zhai, Zhen-Hua. "A study of fatigue crack initiation and early propagation /." Thesis, McGill University, 1988. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=75900.

Full text
Abstract:
This thesis proposes a quantitative model of fatigue crack initiation and early propagation based on a plastic strain intensity factor $ Delta{K} sb{p}$. In this model, the crack growth rate in the initiation region is simplified as a straight line on the log-log scale of da/dN verses $ Delta{K} sb{p}$ curve. A turning point which divides crack growth into the initiation and propagation regions is introduced as the plastic crack propagation threshold, $ Delta{K} sb{pth}$, whose value is determined by the plastic crack propagation threshold in the $ Delta{J}$-integral form, $ sqrt{ Delta{J} cdot{E}} sb{pth}$. The crack propagation style in the initiation region up to the plastic crack propagation threshold is Stage I propagation. This thesis also proposes a Stage I crack propagation model for cyclindrical specimens which consists of a model of sub-microcrack propagation prior to the sub-threshold and a model of the subsequent microcrack propagation. Crack profile changes and closure effect in the initiation region are also qualitatively proposed. The results of an experimental study carried out on smooth cylindrical specimens of polycrystalline OFHC copper at room temperature are compared with the proposed models. The coated and shadowed replicas viewed by SEM traced a fatal or main surface crack in a specimen back to a size of less than one micron. A combination of the replication technique and post-mortem specimen surface and fractographic surface examination by SEM provided good information of crack initiation and Stage I propagation. The results support the proposed models. The integration of the crack growth rate as a function of the plastic strain intensity factor yields a fatigue crack initiation life estimate whose error is less that 5%. For comparison, the experimental data presented in this paper is also discussed on the basis of $ Delta{K}$ and $ Delta{K} sb{eff}$ parameters proposed by other researchers.
APA, Harvard, Vancouver, ISO, and other styles
41

Manjunatha, Chikkamadal Mallappa. "Oxidation assisted fatigue crack propagation behaviour in structural steels." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363317.

Full text
APA, Harvard, Vancouver, ISO, and other styles
42

Kwon, Young W. "A numerical study of dynamic crack propagation in composites." Thesis, Monterey, California. Naval Postgraduate School, 1992. http://hdl.handle.net/10945/23735.

Full text
APA, Harvard, Vancouver, ISO, and other styles
43

KUNIEDA, Minoru, Keisuke KAWAMURA, Hikaru NAKAMURA, and Khoa K. TRAN. "QUANTITATIVELY EVALUATION OF CRACK PROPAGATION DUE TO REBAR CORROSION." 日本コンクリート工学会, 2010. http://hdl.handle.net/2237/20926.

Full text
APA, Harvard, Vancouver, ISO, and other styles
44

KENEDI, PAULO PEDRO. "ESTIMATION OF FATIGUE CRACK PROPAGATION RATES FROM CYCLIC MECHANICAL." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1991. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=19342@1.

Full text
Abstract:
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
FUNDAÇÃO DE APOIO À PESQUISA DO ESTADO DO RIO DE JANEIRO
COMISSÃO NACIONAL DE ENERGIA NUCLEAR
INSTITUTO DE PESQUISAS DA MARINHA
Este trabalho tem como objetivo a proposição de um modelo que correlacione duas metodologias de projeto à fadiga, o método EN e a Mecânica da Fratura Linear Elástica (MFLE), tradicionalmente utilizada de forma estanque para se estimar a vida residual de peças à fadiga estrutural. Para tal um modelo foi construído à partir de hipóteses e limitações bem estabelecidas, com cada passo explicitamente mostrado e comentado. Alguns aperfeiçoamentos ao modelo proposto foram implementados e seus resultados avaliados. Finalmente através da comparação das curvas geradas pelos modelos com as curvas dos resultados experimentais de 4 materiais, cujas propriedades mecânicas retiramos da literatura, validamos os modelos propostos.
The objective of this work is to propose a model to correlative two metodologies of fatigue design, the EN Method and the Linear Elastic Fracture Mechanics, traditionaly used in a separate way, to estimate the residual life of components subjected to estrutural fatigue. For this purpose a model was built based on well estabilished hipotesis and limitations, where every step was explicitaly explained in detail. Some improvement to the model were estabilished and their results evaluated. Finally a comparasion between the curves generated by the models with the curves of experimental results of four materials, which mechanical properties were documentaded in especific literature, we confirm the vality of the proposed models.
APA, Harvard, Vancouver, ISO, and other styles
45

Gonçalves, da Silva Bruno Miguel. "Modeling of crack initiation, propagation and coalescence in rocks." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/55156.

Full text
Abstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2009.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 254-260).
Natural or artificial fracturing of rock plays a very important role in geologic processes and for engineered structures in and on rock. Fracturing is associated with crack initiation, propagation and coalescence, which have been studied experimentally and analytically by many researchers. The analytical models developed to describe the initiation and propagation of cracks in brittle materials can be incorporated in Finite Element (FE) and Displacement Discontinuity (DD) codes. Corresponding research has been going on at MIT and has led to the development of a DDM code - FROCK - which currently uses a stress-based criterion proposed by Bobet (1997) to model crack initiation and propagation. Even though the predictions obtained with this criterion generally correspond to the experimental results, there are cases, in which the results obtained with FROCK are not satisfactory. This thesis proposes and implements new crack initiation and propagation criteria in the DDM code FROCK, namely a strain-based criterion and two stress-dependent criteria. It also studies the crack initiation and propagation processes numerically, using the FEM code ABAQUS. Existing crack initiation and propagation criteria (stress, strain and energy based) are also investigated with ABAQUS. The crack development processes are studied by modeling pairs of pre-existing flaws (double-flaw geometries) embedded in specimens subjected to vertical compressive loads in both ABAQUS and FROCK. For the different flaw arrangements studied, the difference between the stress and strain fields around the flaw tip gradually increases as the horizontal distance between the inner flaw tips increases. In terms of crack initiation, the results obtained with the stress and strain-based criteria studied were more consistent with the experimental observations than the results obtained with the energy-based criterion. The proposed strain-based criterion implemented in FROCK yielded better results than Bobet's stress-based criterion currently used in FROCK, for the five flaw arrangements studied. The results obtained with the two proposed stress-dependent criteria indicate that the critical shear stress at which a crack propagates in rock does not depend upon the normal stress applied, since the best crack propagation results were obtained for very low or zero friction angles.
by Bruno Miguel Gonçalves da Silva.
S.M.
APA, Harvard, Vancouver, ISO, and other styles
46

Zhuang, Linqi. "Fiber/matrix interface crack propagation in polymeric unidirectional composite." Licentiate thesis, Luleå tekniska universitet, Materialvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-17391.

Full text
Abstract:
Fiber/matrix interface cracking plays an important role in determining the final failure of unidirectional composites. In the present study, energy release rate (ERR) for fiber/matrix interface debond growth originated from fiber break in unidirectional composite is calculated using 5-cylinders axisymmetric and 3-D FEM models with hexagonal fiber arrangement. In the model the debonded fiber is central in the hexagonal unit which is surrounded by effective composite. The effect of neighboring fibers focusing on local fiber clustering on the ERR is analyzed by varying the distance between fibers in the unit. Two different scenarios are considered, one is the steady-state debond where debond are long and thus there is no interaction between debond tip and fiber break; the other case is when debond are relatively short when debond tip interacts with fiber break. The steady-state ERR is calculated from potential energy difference between a unit in the bonded region far away from the debond front and a unit in the debonded region far behind the debond front. The ERR for different modes of crack propagation is obtained from a FEM model containing a long debond by analyzing the stress at the debond front. For very short debonds, the ERR was calculated by both the J integral and the Virtual crack closure technique (VCCT).For steady-state debond growth, results show that in mechanical axial tensile loading fracture Mode II is dominating, it has strong angular dependence (effect of closest fibers) but the average ERR is not sensitive to the local fiber clustering. In thermal loading the Mode III is dominating and the average ERR is highly dependent on the distance to neighboring fibers. For short debod growth, results show that the debond growth is Mode II dominated and that the ERR strongly depends on the angular coordinate. The local fiber clustering has larger effect on the angular variation for shorter debonds and the effect increases with larger local fiber volume fraction. Finally, the ERR values from 5-cylinder axisymmetric model could be considered as upper bound for the 3-D hexagonal model.
Godkänd; 2016; 20160415 (linzhu); Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Linqi Zhuang Ämne: Polymera konstruktionsmaterial/Polymeric Composite Material Uppsats: Fiber/Matrix Interface Crack Propagation in Polymeric Unidirectional Composite Examinator: Professor Janis Varna, Avdelningen för materialvetenskap, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet, Luleå. Diskutant: PhD, R&D Manager Anders Holmberg, ABB AB Composites, Piteå. Tid: Fredag 27 maj, 2016 kl 15.00 Plats: F531, Luleå tekniska universitet
APA, Harvard, Vancouver, ISO, and other styles
47

Genussov, Ron M. S. "Rapid crack propagation in pipe grades of poly-ethylene." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47444.

Full text
APA, Harvard, Vancouver, ISO, and other styles
48

Horne, Michael R. "Rayleigh Wave Acoustic Emission during Crack Propagation in Steel." Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/28780.

Full text
Abstract:
An investigation was conducted of the existence of seismic surface pulses (SSP) on crack faces in near-failure fatigue. An SSP has components of various modes of wave propagation. The component with the largest amplitude is a Rayleigh surface wave pulse. The possibility that these surface modes have much higher amplitudes than bulk modes of acoustic emission (AE) was illustrated by an idealized thought experiment relating an SSP on a half-space to the response of crack faces to crack extension. A number of aspects of AE monitoring in finite objects were investigated. Attributes of surface wave propagation on the edge of a specimen were found to be easier to monitor than other modes of wave propagation. Wavelet analysis was used to compare the characteristics of brittle AE with other sources. A new testing paradigm was developed to reduce interference from secondary sources of AE and enhance the investigation of AE from critical crack behavior. Unique specimen design features were developed, data acquisition features sought and validated, a dead weight load frame was modified, and data analysis procedures were developed. Criteria based on velocity, frequency content, amplitude and shape were devised to determine if an AE event is an SSP. The tests were designed to mimic load conditions on structures such as bridges and hence investigate the difference between AE generated in field conditions and that of typical laboratory conditions. Varieties of steel, from very ductile to very brittle, were tested. It was concluded that plastic zone formation, considered a secondary source of AE, was found not to interfere with the SSP activity. The SSP was found experimentally to have 2-3 times the amplitude of the bulk wave AE. The lack of sufficient AE did not allow for determination of conclusive changes in the AE as the specimens approached failure. However, it was found that brittle crack extension in fatigue and ductile failure can produce wave propagation resembling the SSP.
Ph. D.
APA, Harvard, Vancouver, ISO, and other styles
49

Arranz, Carreño Aurelio. "Discontinuous Galerkin methods for elasticity and crack propagation problems." Thesis, University of Oxford, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.558688.

Full text
Abstract:
A new set of numerical methods for predictive modelling of quasistatic and dynamic crack propagation in brittle materials for aerospace applications based upon the Symmetric Interior Penalty Galerkin Method (SIPG) and the Nonsymmetric Interior Penalty Galerkin Method (NIPG) is proposed. This new approach to solving problems in Computational Fracture Mechanics belongs to the family of Discontinuous Galerkin Finite Element Meth- ods (DGFEMs) and draws on the qualities of both the classical Finite Element Methods (FEMs) and Finite Volume Methods (FVMs) in order to overcome the shortcomings and limitations which both methods exhibit when trying to address the transition from contin- uum to discontinuum during material fracture. This thesis focuses mainly on the numerical linear algebra aspects associated with the two above DGFEM methods when applied to crack propagation problems. A new precondi- tioning technique for the iterative solution of linear systems of equations is introduced and its qualities are presented by means of numerical examples. A coupling technique with pre- conditioners for conforming approximations is also introduced. Several improvements and extensions to the original technique are presented to make crack propagation simulations with the SIPG viable. Results for both quasistatic and dynamic fracture propagation are presented. Practical aspects ofthe implementation are also discussed, revealing the important issues that still have to be addressed and that constitute paths for further research.
APA, Harvard, Vancouver, ISO, and other styles
50

Rösch, Frohmut. "Atomistic dynamics of crack propagation in complex metallic alloys." [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-35984.

Full text
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the bibliographies on the topic 'Crack propagation' for other source types:
Journal articles Books
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography