Academic literature on the topic 'Rupture criterion'
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Journal articles on the topic "Rupture criterion":
1
Li Shiyu. "Earthquake rupture model and rupture criterion." Physics and Chemistry of the Earth 17 (January 1990): 55–61. http://dx.doi.org/10.1016/0079-1946(89)90009-8.
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Walczak, Jan. "On an energy creep-rupture criterion." International Journal of Mechanical Sciences 28, no. 2 (January 1986): 71–81. http://dx.doi.org/10.1016/0020-7403(86)90015-9.
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Varble, Nicole, Gabriel Trylesinski, Jianping Xiang, Kenneth Snyder, and Hui Meng. "Identification of vortex structures in a cohort of 204 intracranial aneurysms." Journal of The Royal Society Interface 14, no. 130 (May 2017): 20170021. http://dx.doi.org/10.1098/rsif.2017.0021.
Abstract:
An intracranial aneurysm (IA) is a cerebrovascular pathology that can lead to death or disability if ruptured. Abnormal wall shear stress (WSS) has been associated with IA growth and rupture, but little is known about the underlying flow physics related to rupture-prone IAs. Previous studies, based on analysis of a few aneurysms or partial views of three-dimensional vortex structures, suggest that rupture is associated with complex vortical flow inside IAs. To further elucidate the relevance of vortical flow in aneurysm pathophysiology, we studied 204 patient IAs (56 ruptured and 148 unruptured). Using objective quantities to identify three-dimensional vortex structures, we investigated the characteristics associated with aneurysm rupture and if these features correlate with previously proposed WSS and morphological characteristics indicative of IA rupture. Based on the Q -criterion definition of a vortex, we quantified the degree of the aneurysmal region occupied by vortex structures using the volume vortex fraction ( vVF ) and the surface vortex fraction ( sVF ). Computational fluid dynamics simulations showed that the sVF , but not the vVF , discriminated ruptured from unruptured aneurysms. Furthermore, we found that the near-wall vortex structures co-localized with regions of inflow jet breakdown, and significantly correlated to previously proposed haemodynamic and morphologic characteristics of ruptured IAs.
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Aubertin, Michel, and Richard Simon. "Un critère de rupture multiaxial pour matériaux fragiles." Canadian Journal of Civil Engineering 25, no. 2 (April 1, 1998): 277–90. http://dx.doi.org/10.1139/l97-092.
Abstract:
Most brittle materials show little straining at failure and an ultimate strength that depends upon loading geometry. The surface that defines failure in stress space has a characteristic shape that may be defined by an appropriate mathematical criterion. In this paper, the authors present a simple multiaxial criterion formulated from two quadric functions. Under conventional triaxial compression, the MSDP criterion reduces to the Mises-Schleicher criterion at low mean stress and it takes the shape of the conical Nadai-Drucker-Prager criterion at higher mean stress. The MSDP criterion can be expressed from the three principal stresses or from the usual invariantsI1, J2, and J3. It includes four characteristic parameters, each having a particular significance regarding material properties. The validity of the criterion is shown using experimental results taken from the literature on rock, concrete, and grey cast iron.Key words: failure, brittle materials, rock, concrete, cast iron.
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Huddleston, R. L. "An Improved Multiaxial Creep-Rupture Strength Criterion." Journal of Pressure Vessel Technology 107, no. 4 (November 1, 1985): 421–29. http://dx.doi.org/10.1115/1.3264476.
Abstract:
An improved strength model is developed for predicting creep rupture under multiaxial stress states. The new model incorporates three independent stress parameters and distinguishes between life under tensile versus compressive stress states. Assessments of the new model based on experimental biaxial creep-rupture data for type 304 stainless steel tested at 593°C show the new model to be significantly more accurate than the classical criteria of von Mises, Tresca, or Rankine.
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Dai, Zongfu, and Shouci Lu. "Liquid bridge rupture distance criterion between spheres." International Journal of Mineral Processing 53, no. 3 (April 1998): 171–81. http://dx.doi.org/10.1016/s0301-7516(97)00078-1.
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Li, Chun Guang, Xiu Run Ge, Hong Zheng, and Shui Lin Wang. "Two-Parameter Parabolic Mohr Strength Criterion and Its Damage Regularity." Key Engineering Materials 306-308 (March 2006): 327–32. http://dx.doi.org/10.4028/www.scientific.net/kem.306-308.327.
Abstract:
A series of formulas about two-parameter parabolic Mohr strength criterion(2-PP Mohr criterion) are derived. Based on the results of uniaxial tension and uniaxial compression tests, the parameters involved in the criterion can be easily determined, then the criterion in terms of the major principal stress and the minor principal stress is derived, and the damage pattern is also discussed. At last, the formulas about the rupture angle and the friction angle are presented, and their relationship is also given. 2-PP Mohr criterion can describe not only shear but also tensile failure. In this criterion the ratio of the uniaxial compression strength and the uniaxial tension strength is not confined as in Griffith criterion. The formula about the rupture angle provides steady theoretical foundation for determining the direction of crack faces and damage patterns in the computation of macro crack propagation. In fact, Griffith criterion is only a special case of the two-parameter parabolic Mohr strength criterion proposed in this present paper.
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Paraskevas, Kosmas I., Alexandros A. Tzovaras, Vassilios Stathopoulos, Fotini Gentimi, and Dimitri P. Mikhailidis. "Increased Fluorodeoxyglucose Uptake Following Endovascular Abdominal Aortic Aneurysm Repair: A Predictor of Endoleak?" Open Cardiovascular Medicine Journal 4, no. 1 (April 8, 2010): 117–19. http://dx.doi.org/10.2174/1874192401004010117.
Abstract:
The main criterion for abdominal aortic aneurysm (AAA) repair is an AAA diameter ≥5.5 cm. However, some AAAs rupture when they are smaller. Size alone may therefore not be a sufficient criterion to determine rupture risk. Fluorodeoxyglucose (FDG) uptake is increased in the presence of inflammation and it was suggested that this may be a better predictor of rupture risk than AAA size. Furthermore, increased FDG uptake following endovascular AAA repair may be an indirect predictor of continuous AAA sac enlargement due to the presence of an endoleak (even if this is not detected by imaging modalities) and/or increased AAA rupture risk. The role of FDG uptake needs to be explored further in the management of AAAs.
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Jusko, Maciej, Piotr Kasprzak, Alicja Majos, and Waclaw Kuczmik. "The Ratio of the Size of the Abdominal Aortic Aneurysm to That of the Unchanged Aorta as a Risk Factor for Its Rupture." Biomedicines 10, no. 8 (August 17, 2022): 1997. http://dx.doi.org/10.3390/biomedicines10081997.
Abstract:
Background: A ruptured abdominal aortic aneurysm is a severe condition associated with high mortality. Currently, the most important criterion used to estimate the risk of its rupture is the size of the aneurysm, but due to patients’ anatomical variability, many aneurysms have a high risk of rupture with a small aneurysm size. We asked ourselves whether individual differences in anatomy could be taken into account when assessing the risk of rupture. Methods: Based on the CT scan image, aneurysm and normal aorta diameters were collected from 186 individuals and compared in patients with ruptured and unruptured aneurysms. To take into account anatomical differences between patients, diameter ratios were calculated by dividing the aneurysm diameter by the diameter of the normal aorta at various heights, and then further comparisons were made. Results: It was found that the calculated ratios differ between patients with ruptured and unruptured aneurysms. This observation is also present in patients with small aneurysms, with its maximal size below the level that indicates the need for surgical treatment. For small aneurysms, the ratios help us to estimate the risk of rupture better than the maximum sac size (AUC: 0.783 vs. 0.650). Conclusions: The calculated ratios appear to be a valuable feature to indicate which of the small aneurysms have a high risk of rupture. The obtained results suggest the need for further confirmation of their usefulness in subsequent groups of patients.
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Gao, C. Y., and Y. T. Fang. "Strain-Based Damage Tolerance of Cylindrical Shells Subjected to Transient Loading and Its Application." Key Engineering Materials 293-294 (September 2005): 501–8. http://dx.doi.org/10.4028/www.scientific.net/kem.293-294.501.
Abstract:
In this paper, a new approach to damage tolerance determination, which is related to the critical rupture strain, is proposed for cylindrical shells subjected to inner transient high-pressure loading. The relation of damage variable and circumferential plastic strain is deduced on the basis of a damage evolution equation as well as a simplified dynamic viscoplastic constitutive equation. The value of damage variable can be obtained then if the strain is known by strain measurement, and the damage tolerance just corresponds to the rupture strain of the structure. Further, the damage tolerance has been applied as the strain-based rupture criterion in the FE simulation of the dynamic fracture process for transient-pressurized cylindrical shells. Especially for the notched shells, the strain concentration effect of notches on the rupture criterion is analyzed quantitatively.
Dissertations / Theses on the topic "Rupture criterion":
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Barthélémy, Jean-François. "Approche micromécanique de la rupture et de la fissuration dans les géomatériaux." Marne-la-vallée, ENPC, 2005. https://pastel.archives-ouvertes.fr/pastel-00001296.
2
Michaut, Vincent. "Modélisation de la fragmentation dynamique par la méthode des éléments discrets." Phd thesis, Ecole Centrale Paris, 2011. http://tel.archives-ouvertes.fr/tel-00601766.
Abstract:
L'objectif de ce travail de thèse a été de modéliser avec une méthode aux éléments discrets la fracturation en tension, et plus particulièrement la fragmentation dynamique, sur des matériaux fragiles pour de hautes vitesses de déformation. La fragmentation est un phénomène irréversible, non linéaire et aléatoire. Elle intervient dans de nombreux domaines de la vie courante, quelque soit l'échelle considérée. La modélisation numérique de ce phénomène permettrait une prédiction de certains paramètres statistiques de la fragmentation, comme le nombre de fragments, la taille des fragments, la distribution de la taille des fragments, etc. Pour cette thèse, la Méthode des Éléments Discrets (DEM) s'est révélée être un excellent moyen pour simuler la fracturation en raison de sa nature discrète. Toutefois, une bonne méthode de simulation numérique ne suffit pas à elle seule pour modéliser la fragmentation dynamique. Un critère de rupture doit également être inséré, afin d'introduire un endommagement. Ce critère de rupture s'écrit au niveau d'un lien entre deux particules et il engendre un dommage, en faisant décroître la contrainte locale jusqu'à l'obtention d'une fissuration discrète. Dans un premier temps, un critère de rupture de Camacho-Ortiz |24| a été introduit dans une méthode aux éléments discrets. Ce critère se traduit par un endommagement en fonction d'une ouverture de fissure. Ce premier critère a donné de bons résultats comparé à ceux de |69, 88, 97, 143-147| sur la convergence des paramètres de la fragmentation sur des cas simples, mais nécessite un grand nombre de particules. Dans un second temps, afin d'envisager la modélisation de la fragmentation sur des cas plus complexes en trois dimensions à de hautes vitesses de déformation, un second critère de rupture a été introduit. Ce critère de rupture s'appuie sur une approche physique différente, qui prend en compte l'hétérogénéité des matériaux fragiles avec leurs défauts susceptibles d'évoluer et de provoquer une rupture locale. Pour cela, il fait intervenir une loi probabiliste de Weibull afin d'introduire des défauts par élément de volume. Ce critère a été développé par C. Denoual, P. Forquin et F. Hild |29, 33, 42-44|. Tout d'abord, ce second critère de rupture a été testé sur des cas simples en obtenant une convergence des paramètres statistiques de la fragmentation avec un nombre environ $10$ fois moins important de particules que pour la première méthode. Un cas plus complexe en trois dimensions de modélisation de barre d'Hopkinson en trois dimensions a permis de tester de manière " qualitative " la méthode.
3
Bui, Thanh Quang. "Caractérisation de l'amorçage de fissure dans les assemblages collés : application à l'adhérence moléculaire renforcée." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4729/document.
Abstract:
L'adhérence moléculaire est une technique d’assemblage basée sur la mise en contact directe de deux surfaces sans utiliser aucune colle ou produit spécifique à l’interface. Une telle opération nécessite que les surfaces à coller soient suffisamment lisses et qu’elles soient suffisamment rapprochées pour provoquer l’adhérence moléculaire. La caractérisation de la tenue mécanique de ce type d’assemblage par des essais mécaniques classiques de type pelage, clivage ou double cisaillement présentent des dispersions de mesures très importantes.Le premier objectif de ce travail concerne la conception et le développement d’un nouvel essai pour l’analyse de l’amorçage de fissure permettant d’obtenir des résultats moins dispersés que les essais classiques notamment pour des colles fragiles de faible épaisseur comme l’adhésion moléculaire. Seul le mode I a été étudié et un montage de type DCB modifié a été proposé pour étudier l’amorçage pour différentes géométries de bord (homogène, concentration de contrainte élevée, …).Le second objectif se propose, en partant des différents résultats expérimentaux obtenues, de comparer des approches (PSC, CC, MZC) qui permettent de prédire l’amorçage de la fissure pour des colles fragiles et en particulier pour l’adhérence moléculaire. L’idée est de proposer une solution simple aux ingénieurs souhaitant prédire la rupture dans un assemblage collé avec une épaisseur de colle tendant vers zéroDirect bonding by molecular adhesion is a bonding technique based on joining two surfaces into direct contact without the use of any adhesives or additional material. Such an operation requires the surfaces that are to be bonded to be sufficiently smooth and for them to be sufficiently close together to allow contact to be initiated. Mechanical characterization of this type of assembly with classical mechanical test as for instance wedge test, cleavage test or double shear test present a highly defects sensitivity on mechanical results.The first objective of this work concerns the design and the development of a new test for the analysis of crack initiation in order to obtain results less dispersed than conventional tests particularly for fragile adhesives with small thickness as molecular bonding. Only the mode I was investigated and an experimental device based on modified DBC classical test is proposed to study crack initiation with different edge geometries (homogeneous, high stress concentration).The second objective proposed, in starting from the different experimental results obtained, to compare some approaches (PSC, CC, MZC) to predict crack initiation for fragile adhesives and in particular for molecular bonding. The idea is to propose a simple methodology for engineers in order to predict fracture in an assembly bonded with an adhesive thickness close to zero
4
Brunel, Jean-Evrard. "Influence de l'endommagement sur la rupture de plaques composites en présence de surcontraintes." Paris 13, 1989. http://www.theses.fr/1989PA132008.
Abstract:
On cherche à définir un critère de rupture d'éprouvettes trouées en matériau composite stratifiés croisé. Des essais de traction statique uniaxiale, menés sur 3 matériaux (T300-5208, T300-6376, T400-6376) agencés sous différentes séquences d'empilement conduisent à déterminer l'influence de la nature du renfort ou de la matrice sur les mécanismes d'endommagement.
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Reck, Bernhard. "Comportement mécanique anisotrope des composites stratifiés carbone/époxyde sous contraintes complexes : élasticité, endommagement, rupture." Université Joseph Fourier (Grenoble), 1994. http://www.theses.fr/1994GRE10183.
Abstract:
L'objet de ce travail est l'analyse experimentale et theorique du comportement mecanique anisotrope de trois types de stratifies composites carbone/epoxyde (unidirectionnel, croise et quasi-isotrope) dans les domaines de l'elasticite, des deformations irreversibles, de l'endommagement et de la rupture, sous sollicitations uniaxiales monotones et cycliques et sous contraintes complexes. L'instrumentation des eprouvettes par des jauges extensometriques a permis d'acceder aux differentes composantes du tenseur des deformations de green-lagrange. Les techniques experimentales tiennent compte des exigences particulieres des materiaux composites par l'utilisation du montage en doubles rotules ponctuelles en traction et du montage de boehler en compression simple et en compression sous pression de confinement. Les essais ont mis en evidence la forte anisotropie des differents stratifies. Pour les orientations hors-axes des stratifies unidirectionnel et croise, la deformation de distorsion joue un role important pour les modes de deformation et de rupture. Le plan du stratifie quasi-isotrope presente un comportement elastique isotrope et un comportement a la rupture anisotrope. A l'aide des essais cycliques, l'endommagement a ete evalue par les mesures des deformations irreversibles, des evolutions des modules directionnels et des variations relatives des modules directionnels en fonction des deformations irreversibles correspondantes. Sous etats de contraintes complexes, le critere de tsai et wu prevoit mal les resistances directionnelles des stratifies unidirectionnel et croise. La generalisation du critere de boehler, qui comporte trois branches correspondant a trois modes de rupture differents, est en tres bon accord avec les resultats experimentaux. Pour le stratifie quasi-isotrope, le critere de tsai et wu prevoit un comportement isotrope a la rupture, ce qui est en contradiction avec les donnees experimentales ; le critere de boehler prevoit correctement le comportement anisotrope a la rupture de ce stratifie
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Raviol, Jolan. "Vers l'évaluation du risque de rupture des anévrismes intracrâniens : caractérisation mécanique in vivo de la paroi artérielle." Electronic Thesis or Diss., Ecully, Ecole centrale de Lyon, 2024. http://www.theses.fr/2024ECDL0011.
Abstract:
Les anévrismes intracrâniens constituent une pathologie critique de santé publique liée à la dégradation de la paroi d’artères cérébrales. Il n’existe actuellement aucune méthode permettant d'estimer le risque de rupture d’un anévrisme qui prenne en compte les propriétés mécaniques in vivo de la paroi anévrismale, pourtant reconnues comme essentielles dans le phénomène de rupture. Ce travail de doctorat s'inscrit dans un projet de grande envergure visant à améliorer les critères d’intervention, actuellement disponibles pour les praticiens, en développant un outil d'aide à la décision non invasif se basant sur l’état mécanique du tissu pour en évaluer la probabilité de rupture. Cet outil reposera sur la définition d'une relation entre la forme de l'anévrisme observé par imagerie clinique et une base de données contenant un ensemble d’images cliniques issues d’études préalables, associées aux propriétés mécaniques in vivo de la paroi et à une caractérisation de sa rupture. Pour produire cette base de données, un dispositif de déformation de la paroi anévrismale est développé dans le cadre du projet global. Ce travail doctoral se focalise sur (1) la calibration, l'optimisation et les tests in vitro de ce dispositif sur artères fantômes et (2) l’application in vivo du dispositif sur un modèle animal d'anévrisme intracrânien. Pour ce faire, un modèle numérique de l'expérimentation in vitro a été implémenté et validé au regard des résultats expérimentaux, grâce au développement d’une méthode de validation originale. Ce modèle éléments finis d’interaction fluide-structure a permis d'appréhender les incertitudes d'utilisation du dispositif au sein de l'anévrisme et d’aider au dimensionnement des artères fantômes. Le meilleur compromis en termes d'épaisseur et de souplesse de la paroi des artères fantômes a ainsi été identifié compte tenu des limites des techniques de fabrication. De plus, une procédure d'analyse inverse a été développée de sorte à estimer les caractéristiques mécaniques de la paroi anévrismale in vivo. Son utilisation repose sur la quantification de la déformation engendrée par le dispositif et visualisée par scanner spectral à comptage photonique, technique d’imagerie médicale émergente dont les résolutions spatio-temporelles permettent une sollicitation contrôlée du tissu sans risque accru de rupture. Les propriétés mécaniques identifiées sont cohérentes avec celles issues des caractérisations ex vivo d'anévrismes similaires disponibles dans la littérature. Enfin, un premier critère de rupture patient-spécifique de la paroi anévrismale, prenant en compte l’état de contrainte in vivo dans le tissu, a été proposéIntracranial aneurysms are a critical public health condition linked to the degradation of the cerebral artery wall. There is currently no method for estimating the risk of aneurysm rupture that takes into account the in vivo mechanical properties of the aneurysm wall, which are believed to be essential in the rupture phenomenon. This doctoral work is part of a large-scale project aimed at improving the intervention criteria currently available to practitioners by developing a non-invasive decision-support tool based on the mechanical state of the tissue to assess the probability of rupture. This tool will be based on the definition of a relationship between the shape of the aneurysm observed by clinical imaging and a database containing a set of clinical images from previous studies, associated with the in vivo mechanical properties of the wall and a characterisation of the rupture. To produce this database, an aneurysm wall deformation device was developed as part of the overall project. This doctoral work focuses on (1) the calibration, the optimisation and in vitro testing of this device on phantom arteries and (2) the in vivo application of the device on an animal model of intracranial aneurysm. To do this, a numerical model of the in vitro experiment was implemented and validated against the experimental results by developing an original validation method. This finite element model of fluid-structure interaction was used to understand the uncertainties involved in using the device within the aneurysm and to help for dimensioning the phantom arteries. The best compromise in terms of phantom artery wall thickness and flexibility was identified, taking into account the limitations of the fabrication techniques. In addition, an inverse analysis procedure was developed to estimate the mechanical characteristics of the aneurysm wall in vivo. Its use is based on quantifying the deformation generated by the device and visualised by spectral photon-counting computed tomography, an emerging medical imaging technique whose spatio-temporal resolutions allow controlled stressing of the tissue without increasing the risk of rupture. The mechanical properties identified were consistent with those derived from ex vivo characterisations of similar aneurysms available in the literature. Finally, a first patient-specific criterion for rupture of the aneurysm wall, taking into account the state of stress in vivo in the tissue, was proposed
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Wehbi, Mickaël. "Modélisation de l'amorçage de la corrosion sous contrainte dans les alliages base nickel 182 et 82 en milieu primaire des réacteurs à eau sous pression." Thesis, Paris, ENMP, 2014. http://www.theses.fr/2014ENMP0056/document.
Abstract:
Les métaux déposés base nickel sont utilisés pour assembler des composants du circuit primaire des centrales nucléaires à Réacteurs à Eau sous Pression (REP). Un nombre croissant de cas de fissuration par Corrosion Sous Contrainte (CSC) des soudures en alliages base nickel 182 et 82 est rapporté dans le retour d'expérience international ce qui motive le développement d'un modèle permettant de prévoir la fissuration par CSC de ces matériaux. Ce mécanisme de dégradation fait intervenir des paramètres matériaux, mécaniques ou environnementaux qui peuvent interagir entre eux. L'objectif de cette étude est de mieux comprendre les mécanismes physiques locaux (aux joints de grains) impliqués dans l'amorçage de fissures de CSC. Un essai de traction sur une éprouvette en alliage 182 préalablement oxydée en milieu primaire simulé a mis en évidence une dispersion de la sensibilité à l'oxydation des différents joints de grains. L'analyse couplée entre oxydation et fissuration a permis, à l'aide de calculs de micro-mécanique sur un agrégat polycristallin synthétique, de proposer un critère de rupture des joints de grains oxydés défini par un couple profondeur d'oxydation/ contrainte locale critique. Compte tenu du rôle clé que tient l'oxydation intergranulaire dans le mécanisme de fissuration par CSC et de la dispersion observée entre les différents joints de grains, une cinétique d'oxydation intergranulaire des alliages base nickel 182 et 82 a été identifiée prenant en compte la précipitation de carbures de chrome, la température ou encore la teneur en hydrogène dissous. Ce modèle cinétique permet d'aborder statistiquement l'oxydation des joints de grains et est intégré à un modèle d'amorçage local. Dans ce dernier l'amorçage, défini par la fissuration de l'oxyde intergranulaire est suivi d'une phase de propagation lente puis rapide jusqu'à une certaine profondeur de fissure. Des hypothèses simplificatrices ont été faites lors de l'identification des lois embarquées dans le modèle de CSC. Toutefois, celles-ci s'avèreront utiles pour cibler les conditions des futurs essais à mener afin de conforter l'identification des différents paramètresNickel base welds are widely used to assemble components of the primary circuit of Pressurized Water Reactors (PWR) plants. International experience shows an increasing number of Stress Corrosion Cracks (SCC) in nickel base welds 182 and 82 which motivates the development of models predicting the time to SCC initiation for these materials. SCC involves several parameters such as materials, mechanics or environment interacting together. The goal of this study is to have a better understanding of the physical mechanisms occurring at grains boundaries involved in SCC. In-situ tensile test carried out on oxidized alloy 182 evidenced dispersion in the susceptibility to corrosion of grain boundaries. Moreover, the correlation between oxidation and cracking coupled with micro-mechanical simulations on synthetic polycrystalline aggregate, allowed to propose a cracking criterion of oxidized grain boundaries which is defined by both critical oxidation depth and local stress level. Due to the key role of intergranular oxidation in SCC and since significant dispersion is observed between grain boundaries, oxidation tests were performed on alloys 182 and 82 in order to model the intergranular oxidation kinetics as a function of chromium carbides precipitation, temperature and dissolved hydrogen content. The model allows statistical analyses and is embedded in a local initiation model. In this model, SCC initiation is defined by the cracking of the intergranular oxide and is followed by slow and fast crack growth until the crack depth reaches a given value. Simplifying assumptions were necessary to identify laws used in the SCC model. However, these laws will be useful to determine experimental conditions of future investigations carried out to improve the calibration used parameters
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Perret, Adrien. "Étude du comportement en post-flambement d’un panneau de fuselage composite infusé avec structures intégrées." Thesis, Toulouse, INPT, 2011. http://www.theses.fr/2011INPT0035/document.
Abstract:
Ces travaux concernent l’étude numérique et expérimentale d’un panneau composite autoraidi fabriqué par le procédé d’infusion de résine (Liquid Resin Infusion LRI). Le procédé LRI permet d’intégrer des structures sur les peaux d’un panneau représentatif d’un fuselage composite. Dans l’étude numérique, des modèles éléments finis sont réalisés, pour étudier le comportement global du panneau en post-flambement. Cela permet de mettre au point un dispositif d’essai. L’approche expérimentale consiste en l’application de différentes méthodes pour contrôler la pièce et réaliser l’essai. Des essais de caractérisation sont aussi réalisés pour obtenir les propriétés mécaniques nécessaires à l’élaboration de modèles numériques locaux, permettant de décrire la décohésion des structures intégréesThese works are related to the numerical and experimental study of a composite stiffened panel, which is manufactured by a resin infusion process (Liquid Resin Infusion LRI). This manufacturing process allows structures to be integrated onto the skins of a panel being representative of a composite fuselage. Finite element models are built along with the numerical study, in order to deal with the post-buckling global behaviour of this panel. This leads to perfect a test set-up addressed during the experimental investigation. Several experimental methods are used to check the test panel and achieve the test. Material properties are also determined through material testing intended for the development of local numerical models, describing the integrated structures decohesion
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Uguen, Alexandre. "Influence de l'endommagement plan sur le comportement hors-plan des composites stratifiés et des assemblages collés." Thesis, Brest, 2017. http://www.theses.fr/2017BRES0004/document.
Abstract:
Les matériaux composites sont utilisés dans le domaine maritime depuis des dizaines d’années que ce soit par exemple pour les éoliennes offshore ou encore les navires militaires étant donné leurs propriétés intrinsèques avantageuses pour de telles applications (faible masse, faible signature magnétique ...). Jusqu’ici les composites employés sont surtout composés de fibres de verre et de matrice polyester. Cependant, les demandes croissantes de navires toujours plus légers et rapides conduisent peu à peu les industriels à se tourner vers les composites à haute performance composés de fibres de carbone et de matrice époxyde. L’utilisation de cette nouvelle génération de matériau nécessite de connaître l’influence de l’endommagement plan, qui peut être d’origine hydrique ou mécanique, sur leur tenue hors-plan. Cette étude a montré une diminution importante de l’enveloppe de rupture du matériau étudié lorsqu’il a séjourné en eau de mer jusqu’à saturation. La résistance en traction hors-plan du composite n’est quant à elle que très peu affectée par la présence de fissures transverses dans le matériau, quel que soit son état de vieillissement. Des travaux ont également été menés sur des assemblages composites collés et mis en avant à la fois la chute de la tenue de l’assemblage due à la présence d’eau de mer dans la matrice époxyde, mais également la nécessité de la prise en compte du couplage endommagement plan/endommagement hors-plan pour la prédiction de la tenue hors-plan de tels assemblages. Enfin, différentes méthodes de prédiction ont été utilisées pour valider les résultats expérimentaux confirmant ainsi l’importance de la prise en compte de l’endommagement plan sur la tenue hors-plan des composites et des assemblages composites collésComposite materials have been used in marine applications for decades for offshore windmills or even battleships because of its intrinsic properties which are assets for such applications (low weight, low magnetic signature...). Until now the composites used are almost made of glass fibers and polyester matrix. However the increasing demand for faster and lighter ships gradually leads manufacturers to turn to high performance composites made of carbon fibers and epoxy matrix. Using this new generation of material requires knowing the influence of the in-plane damage which can be due to water or mechanical damage on its out-of-plane strength. This study has shown a significant reduction of the out-of-plane failure envelope of the studied material after an extended stay in seawater until the saturation point.The out-of-plane tensile strength of the composite is very little affected by transverse cracking in the material whatever the aging state. Work has also been carried out on composite bonded assemblies and pointed out, on the one hand, the drop of the assembly strength because of the water aging and, on the other hand, the necessity to take into account the coupling between in-plane and out-of-plane damage for the prediction of the out-of-plane strength of such assemblies. Finally, different methods of prediction have been used to validate the experimental results confirming the importance to take into account the in-plane damage to predict the out-of-plane strength of composites and composite bonded assemblies
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Le, Pavic Jérémy. "Méthodologie de dimensionnement d’un assemblage collé pour application aérospatiale." Thesis, Brest, École nationale supérieure de techniques avancées Bretagne, 2018. http://www.theses.fr/2018ENTA0001/document.
Abstract:
Les lanceurs spatiaux sont des structures complexes associant une multitude de composants. L’assemblage de ces éléments doit répondre à un niveau de performance élevé. Le collage structural demeure un bon candidat en raison des nombreux avantages qu’il présente. Cependant, cette technologie montre des inconvénients. En raison des changements brusques de géométrie et de propriétés matériaux, des concentrations de contraintes apparaissent aux extrémités du joint de colle. Ce phénomène appelé effets de bords est néfaste pour la tenue mécanique de l’assemblage collé. La présence des effets de bords exclut l’utilisation de critères en contrainte utilisés classiquement. Le dimensionnement d’assemblages collés requiert des outils fiables prenant en compte ces effets de bords. Dans cette étude, un modèle de ruine incrémentale, associant une approche en contrainte et en énergie, est utilisé. L’utilisation de cet outil dans un cadre industriel, impose de répondre aux besoins d’un Bureau d’Études, notamment en termes de coût de calculs. Afin de le diminuer, une implémentation semi-analytique, est tout d’abord développée. Puis, une seconde méthode d’implémentation, basée sur la méthode des Eléments Finis, permet une prévision plus précise de la ruine d’un assemblage. La pertinence de ces deux approches a été vérifiée pour plusieurs configurations de joints collés. Des campagnes d’essais, destinées à confronter les résultats expérimentaux aux prévisions numériques, ont été réalisées. Dans le cadre de ce travail, un montage de collage et d’essai pour assemblages tubulaires a en particulier été développé. L’objectif du pré-dimensionnement est d’identifier une zone d’intérêt dans l’ensemble du domaine d’étude. Aussi, une étude paramétrique peut être requise afin de réaliser cette tâche. Afin de réduire le coût de calcul, une méthode d’interpolation spatiale appelée Krigeage a été mise en œuvre, et permet la construction efficace d’une surface de réponseSpace Launchers are complex structures composed of a large number of elements. The assembling of these components must show a high level of reliability. The use of adhesive bonding technology is an interesting solution since it presentsseveral assets compared to “classical” joint techniques (such as riveting, bolting and welding), mainly because it can help to construct lighter and less energy consuming systems However„ the implementation of adhesives also has somedrawbacks. Due to the strong variations of geometrical and material properties, stress concentrations appear at the extremities of the joint. This phenomenon; called edge effects; has a great influence on the failure of the bond. As a result, the simple use of a classical stress or energetic criteria is not appropriate to predict the fracture of such structures. Therefore, it is obvious that the design of bonded assemblies requires reliable tools to take the edge effects into account. In this work an incremental failure model, which combines the stress and energetic criteria, is used. In order to decrease the computational cost, a semi-analytical application of this model is proposed. This is intended to make the approach more interesting to be implemented in an industrial environment. The accuracy of the prediction of the failure load is enhanced by means of the Finite Element method. The reliability of both the semi-analytical and Finite Element approaches is verified by comparing the model predictions with experimental data issued from double-notched Arcan and tubular specimen geometries. The aim of the pre-design phase is to identify the critical area in the whole range of the application of the studied geometry. Therefore, the realization of a parametric study is required in order to build a response surface. In the present study, this has been achieved by means of spatial interpolation using the Kriging model
Books on the topic "Rupture criterion":
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Eleftheriou, Despina, and Paul A. Brogan. Paediatric vasculitis. Oxford University Press, 2013. http://dx.doi.org/10.1093/med/9780199642489.003.0136.
Abstract:
Systemic vasculitis is characterized by blood vessel inflammation which may lead to tissue injury from vascular stenosis, occlusion, aneurysm, and/or rupture. Apart from relatively common vasculitides such as Henoch-Schönlein purpura (HSP) and Kawasaki's disease (KD), most of the primary vasculitic syndromes are rare in childhood, but are associated with significant morbidity and mortality. New classification criteria for childhood vasculitis have recently been proposed and validated. The cause of most vasculitides is unknown, although it is likely that a complex interaction between environmental factors such as infections and inherited host responses trigger the disease and determine the vasculitis phenotype. Several genetic polymorphisms in vasculitis have now been described that may be relevant in terms of disease predisposition or development of disease complications. Treatment regimens continue to improve, with the use of different immunosuppressive medications and newer therapeutic approaches such as biologic agents. We provide an overview of paediatric vasculitides focusing on HSP, KD, and polyarteritis nodosa (PAN). Key differences (where relevant) between paediatric and adult vasculitis are highlighted. In addition we discuss new emerging challenges particularly in respect to the long-term cardiovascular morbidity for children with systemic vasculitis, and emphasize the importance of future international multicentre collaborative studies to further increase and standardize the scientific base of investigating and treating childhood vasculitis.
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Álvarez Álvarez, Harold. Eco-contabilidad : propuesta para la fundamentación teórica de la T3C. Universidad Libre Cali, 2020. http://dx.doi.org/10.18041/978-958-5545-90-8.
Abstract:
La investigación contable latinoamericana se ha caracterizado fundamentalmente por la interpretación y aplicación de los constructos teóricos y las regulaciones que han sido creadas en los países desarrollados. Algunos investigadores han asumido un juicio crítico con respecto a este proceso a-crítico y no reflexivo de transferencia voluntaria o impositiva de las teorías y normas o estándares creados en otras latitudes. El presente texto hace parte de una tercera categoría, correspondiente a una investigación propositiva, la cual pretende hacer parte de un proyecto de construcción de una nueva contabilidad; no se trata de ajustes parciales, adición de criterios de reconocimiento, nuevos métodos de medición, inclusión de revelaciones o modificación a la estructura conceptual; si bien la propuesta incluye lo mencionado anteriormente, va mucho más allá, se trata de reconstruir el saber contable desde sus bases ontológicas, epistemológicas, metodológicas, praxeológicas, teleológicas y axiológicas. Se trata del germen de una nueva contabilidad comprometida con el interés social, con la biodiversidad y el multiculturalismo, es decir, con la sustentabilidad; a todo este proceso los autores lo han denominado Eco-Contabilidad. La eco-contabilidad compromete a todos los actores sociales para alcanzar sus fines morales superiores; la contabilidad es un saber tan importante y con tantas implicaciones para la presente y futuras generaciones, que requiere la participación directa de la sociedad en general en su concepción, desarrollo y control. Señala Suárez et al (2020) que “el contar del contador es moral” (69), en tal sentido implica una conciencia ecológica, propio de una contabilidad que nace pública, y configura su condición de ciencia social por abordar de forma comprometida los problemas de la sociedad (27). En tal sentido, el autor hace hincapié en la probidad como actuar íntegro y honrado que va más allá de la ley, en fidelidad con los ideales y sujetos siempre al bien común (61-62). La eco-contabilidad es concebida por Franco (2019) como un saber subrogado superior que integra otras aristas de la contabilidad, que se ocupa del control de la riqueza ecológica y que tiene por finalidad la preservación de la vida, a través de los principios de responsabilidad, balance, compensación y de vida. La lectura del libro “Eco-Contabilidad. Propuesta para la fundamentación teórica de la T3C” constituye un paso decisivo en la ruptura paradigmática con la contabilidad tradicional caracterizada por la financiarización, la acumulación y el antropocentrismo economicista. Durante las últimas décadas autores vinculados a las corrientes críticas y alternativas han acopiado las falencias, fallas e incoherencias de la contabilidad financiera regulada, la cual se muestra alejada del interés general, abandona el bien común para insertarse como instrumento al servicio de la especulación y el despojo de las riqueza ambiental y social de los pueblos. Los autores del presente libro, conocedores de la existencia de dichas investigaciones críticas, han decidido dar un paso más adelante, el cual materializan a través de una rigurosa propuesta de fundamentación teórica de lo que debe representar la nueva contabilidad. La Eco-Contabilidad no constituye una propuesta de reforma a la contabilidad convencional, no es un ajuste a los instrumentos tradicionales del hacer contable. La Eco-Contabilidad pretende contribuir a una verdadera revolución científica, no es perfeccionamiento del paradigma vigente, es un cambio profundo de paradigma. La Eco-Contabilidad no es un ajuste a las hipótesis auxiliares del programa de investigación del modelo contable financiero; es en realidad, un cambio de núcleo, lo que implica la invitación a una palingenesia contable, a construir una nueva contabilidad desde sus cimientos. El desafío propuesto abarca reconstruir, repensar, reorientar e incluso construir de nuevo muchos de los elementos del ser y del deber ser contable.
Book chapters on the topic "Rupture criterion":
1
Di Iorio, S., L. Briottet, Edgar F. Rauch, and D. Guichard. "Damage Mechanisms and Rupture Criterion of PM Ti-6Al-4V at 20K." In Materials Science Forum, 287–90. Stafa: Trans Tech Publications Ltd., 2005. http://dx.doi.org/10.4028/0-87849-964-4.287.
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Sandström, Rolf. "Tertiary Creep." In Basic Modeling and Theory of Creep of Metallic Materials, 233–56. Cham: Springer Nature Switzerland, 2024. http://dx.doi.org/10.1007/978-3-031-49507-6_12.
Abstract:
AbstractIn the tertiary stage, the creep rate is continously increasing eventually leading to rupture. Many mechanisms can contribute to the increasing creep rate such as particle coarsening, substructure coarsening, cavitation, changes in the dislocation density and necking. A large number of empirical models exist for the description of tertiary creep and the development of creep damage not least in the context of continuum damage mechanics (CDM). However, there are also basic models. An equation is presented that can describe the whole creep strain versus time curve. Only parameters that are already defined for secondary creep are needed. During the tertiary stage the true applied stress increases rapidly and faster than the counteracting dislocation strength, which is one main reason for the increase in the creep rate during the tertiary stage. Cavitation is of importance, but the cavitation is often local and therefore gives a modest contribution to the creep rate. According Hart’s criterion, necking starts right at the beginning of the tertiary stage. But the necking is not fully developed until close to rupture. This is demonstrated both by uniaxial and multiaxial models and it is also consistent with available experimental data.
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Aplin, P. F., and G. F. Eggeler. "Multiaxial Stress Rupture Criteria for Ferritic Steels." In Mechanics of Creep Brittle Materials 1, 245–61. Dordrecht: Springer Netherlands, 1989. http://dx.doi.org/10.1007/978-94-009-1117-8_18.
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Jain, Appurva, and Abhishek Mishra. "Computation of Rupture Strain from Macroscopic Criteria." In Lecture Notes in Mechanical Engineering, 765–69. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-5463-6_68.
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Webster, G. A. "Determination of Multiaxial Stress Creep Deformation and Rupture Criteria." In Harmonisation of Testing Practice for High Temperature Materials, 289–93. Dordrecht: Springer Netherlands, 1992. http://dx.doi.org/10.1007/978-94-011-2888-9_14.
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Stein, E., and U. Heemann. "Failure Criteria on Creep Rupture of Mineral Salt Based on Micromechanical Mechanisms." In Mechanics of Creep Brittle Materials 2, 160–71. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3688-4_14.
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Xia, Ming-ming, Jun-long Wang, Jian-ping Zhu, Chao Tian, and Jia-jia Liu. "Analytical Method Research of Source Term for Steam Generator Tube Rupture Accident of Small Modular Reactor." In Springer Proceedings in Physics, 1114–20. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-1023-6_95.
Abstract:
AbstractBased on the full reference to the existing engineering practice and safety review experience, and considering the actual design characteristics of the small modular reactor ACP100, a set of source term analysis method suitable for ACP100 of the steam generator tube rupture (SGTR) accident is proposed, and the source term analysis and consequence evaluation of ACP100 SGTR accident was carried out using this method. The analysis shows that the radiological consequences of the accident source term calculated by this method meet the acceptance criteria of small modular reactor. The analysis results of this article can provide support for the follow-up review of accident source term of ACP100.
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Louchet, Francois. "Deformation, Fracture, and Friction Processes." In Snow Avalanches, 14–24. Oxford University Press, 2020. http://dx.doi.org/10.1093/oso/9780198866930.003.0003.
Abstract:
The main mechanical and physical quantities and concepts ruling deformation, fracture, and friction processes are recalled, with particular attention paid to the simplicity of the analysis, but without betraying the scientific validity of the arguments. We particularly discuss the difference between between elastic and plastic deformation, and quasistatic and dynamic loadings, essential in avalanche triggering mechanisms. The physical origin of Griffith’s rupture criterion that rules both fracture nucleation and propagation, and the transition between brittle and ductile failure processes, is thoroughly discussed. We also explain the physical meaning of the classical Coulomb’s friction law, showing why it can hardly apply to a non-conventional porous, brittle, and healable solid like snow.
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Teoh, S. H. "CREEP RUPTURE PREDICTION OF PLASTICS USING A MECHANICAL MODEL AND AN ENERGY RELATED FAILURE CRITERION." In Proceedings of the Fourth International Conference on Durability of Building Materials and Components, 348–55. Elsevier, 1987. http://dx.doi.org/10.1016/b978-1-4832-8386-9.50048-6.
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Gao, Quanping, and Xiaoli Song. "Seepage Exploration on a Landslide in a Hydroelectric Power Station." In Advances in Transdisciplinary Engineering. IOS Press, 2022. http://dx.doi.org/10.3233/atde220950.
Abstract:
Landslide stability analysis is the basement of landslide research. To study the influence of water on reservoir landslide stability, taking a landslide for example in a hydroelectric power station based on detailed field investigation and reservoir operation data, the geological conditions, reservoir and rainfall were considered, the slope failure pattern under natural state and rain state were simulated with Mohr-Coulomb criterion after an numerical three-dimensional model established by the fast Lagrange analysis of continua in 3-dunebsion. A simulation was made for the sliding direction under limit equilibrium situation. The change laws of stability were analyzed under self-gravity, rainfall and reservoir water fluctuation. The distribution characteristics of plastic deformation, displacement and potential sliding surface inside slope were intuitively showed under different conditions. From the point of instability mechanism, water is one of the important factors inducing landslide instability. The key block is suddenly broken with shear rupture that triggers landslide. It offers a reliable basis for both prediction of second landslide induced by rainfall and disaster prevention.
Conference papers on the topic "Rupture criterion":
1
Swindeman, Robert, Weiju Ren, and Michael J. Swindeman. "The Significance of the Tertiary Creep Criterion in Setting Time-Dependent Allowable Stresses." In ASME 2015 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/pvp2015-45981.
Abstract:
The database for Alloy 800H was reviewed with respect to the initiation of tertiary creep and subsequent rupture. Data covered temperatures in the range of 600 to 1000°C and times to 100,000 hours. The establishment of the time to initiate tertiary creep presented a problem because of the non-classical behavior of creep often exhibited in the creep curves. Stress values based on the current tertiary creep and rupture criteria were compared for several heats of material considering both classical and non-classical creep data. Fits to tertiary creep showed more scatter and it was found that 80% of the minimum stress for tertiary creep was generally lower than 67% of the minimum stress to rupture. Using only data from classical curves did produce stress values higher than those from the rupture criterion.
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Zaitsev, Dmitry, Andrey Semenov, and Oleg Kabov. "Viscosity Effect on Thermocapillary Rupture of Falling Liquid Films." In 2010 14th International Heat Transfer Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ihtc14-23222.
Abstract:
Rupture of a subcooled liquid film flowing over an inclined plate with a 150×150 mm heater is studied for a wide range of liquid viscosity (dynamic viscosity μ = (0.91–17.2)x10−3 Pa·s) and plate inclination angle with respect to the horizon (Θ = 3–90 deg). The main governing parameters of the experiment and their respective values are: Reynolds number Re = 0.15–54, heat flux q = 0–224 W/cm2. The effect of the heat flux on the film flow leads to the formation of periodically flowing rivulets and thin film between them. As the heat flux grows the film thickness between rivulets gradually decreases, and, upon reaching a certain threshold heat flux, qidp, the film ruptures in the area between the rivulets. The threshold heat flux increases with the flow rate of liquid and with the liquid viscosity, while the plate inclination angle has little effect on qidp. Criterion Kp, which is traditionally used in the literature to predict thermocapillary film rupture, was found to poorly generalize data for high viscous liquids (ethylene glycol, and aqueous solutions of glycerol) and also data for Θ≤45 deg. The criterion Kp was modified by taking into account characteristic critical film thickness for film rupture under isothermal conditions (no heating), deduced from existing theoretical models. The modified criterion has allowed to successfully generalize data for whole ranges of μ, Re, Θ and q, studied.
3
Doyle, Barry J., and Tim M. McGloughlin. "The Relationship Between Wall Stress and 3D Asymmetry in Repaired and Ruptured Abdominal Aortic Aneurysms." In ASME 2010 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2010. http://dx.doi.org/10.1115/sbc2010-19142.
Abstract:
Abdominal aortic aneurysm (AAA) is a permanent dilation of the infrarenal aorta and is defined as having a diameter 50% greater than the original diameter. If left untreated, an AAA will continue to expand until rupture. The maximum diameter is currently the primary indicator of rupture-risk with AAAs > 5.5 cm deemed a likely to rupture. There have, however, been many reports identifying the inadequacies of the maximum diameter criterion to accurately determine the threat of rupture. It is believed by many researchers that there is a need to review the decision of surgical intervention based solely on aneurysm diameter, and rather include other relevant risk factors. These additional risk factors could, for example, include, AAA wall stress, AAA expansion rate, degree of asymmetry, presence of intraluminal thrombus (ILT), and hypertension. The addition of these parameters may aid the surgical decision-making process. A previous report by our group identified the relationship between asymmetry and posterior wall stress in patient-specific cases [1,2] and as over 80% of ruptures occur on the posterior wall [3] this finding may have significant clinical relevance. In this previous report, the study group was limited to 15 cases and asymmetry was only measured in the anterior-posterior plane. This current paper furthers this previous work by increasing the cohort to 40 cases of electively repaired AAAs and also examines 8 cases of ruptured AAAs. The methodology has been improved to now measure asymmetry in all three dimensions (3D).
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Speelman, Lambert, E. Marielle H. Bosboom, Femke A. M. V. I. Hellenthal, Geert Willem H. Schurink, Micheal J. H. M. Jacobs, and Frans N. van de Vosse. "99 Percentile Wall Stress and Not Peak Stress Correlates With AAA Diameter." In ASME 2008 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2008. http://dx.doi.org/10.1115/sbc2008-191986.
Abstract:
Abdominal Aortic Aneurysm (AAA) is a dilation of the aorta of at least 50% increase in diameter, or an aortic diameter over 3 cm. If left untreated, an AAA will increase in size until rupture of the aortic wall causes a life threatening hemorrhage [1]. The current criterion for a repair procedure is a maximum diameter of the AAA of at least 5.5 cm. However, the diameter is not adequate for some small AAAs that rupture early [2]. Therefore, multiple studies have focused on and published data on patient-specific wall stress analyses. Fillinger et al. (2002) found higher peak wall stresses in ruptured AAAs than in electively repaired AAAs [3].
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Maruyama, Kouichi, Nobuaki Sekido, and Kyosuke Yoshimi. "A Proposal for Post-Assessment Test of Long-Term Creep Rupture Strength of Grade 91 Steel." In ASME 2018 Symposium on Elevated Temperature Application of Materials for Fossil, Nuclear, and Petrochemical Industries. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/etam2018-6706.
Abstract:
Predictions as to 105 hrs creep rupture strength of grade 91 steel have been made recently. The predictions should be verified by some means, since they are based on certain assumptions. A formula for predicting long-term creep rupture lives should correctly describe long-term data points used in its formulation. Otherwise the formula cannot properly predict further longer-term creep rupture lives. On the basis of this consideration, the predictions are examined with long-term creep rupture data of the steel. In the predictions three creep rupture databases were used: data of tube products of grade 91 steel reported in NIMS Creep Data Sheet (NIMS T91 database), data of T91 steel collected in Japan, and data of grade 91 steel collected by an ASME code committee. Short-term creep rupture data points were discarded by the following criteria for minimizing overestimation of the strength: selecting long-term data points with low activation energy (multi-region analysis), selecting data points crept at stresses lower than a half of proof stress (σ0.2/2 criterion), and selecting data points longer than 1000 hrs (cut-off time of 1000 hrs). In the case of NIMS T91 database, a time-temperature parameter (TTP) analysis of a dataset selected by the multi-region analysis can properly describe the long-term data points. However, the TTP analyses of datasets selected by the σ0.2/2 criterion and by the cut-off time of 1000 hrs from the same database overestimate the long-term data points. The different criteria for data selection have more substantial effects on predicted values of the strength of the steel than difference of the databases.
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Margolin, B. Z., A. G. Gulenko, and A. A. Buchatsky. "Prediction of Creep-Rupture Properties for Austenitic Steels Undergone Neutron Irradiation." In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77084.
Abstract:
The paper presents the physical and mechanical model that allows predicting fracture of materials subjected to neutron irradiation under creep. The model is based on the equations of void nucleation and growth on grain boundaries that were proposed earlier. The equations are developed for the case of neutron irradiation of a material. The constitutive equations describing viscoplastic deformation of a material with regard to void evolution are formulated. The criterion of microplastic collapse of a unit cell is used as a fracture criterion. The creep-rupture strength and ductility of austenitic materials in the initial and irradiated conditions with different neutron flux levels are predicted on the basis of the model. The calculated results are compared with the available experimental data.
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Maldonado, Natalia, Adreanne Kelly, Yuliya Vengrenyuk, John T. Fallon, Renu Virmani, Luis Cardoso, and Sheldon Weinbaum. "Human Coronary Microcalcifications: 3D High Resolution Characterization of Frequency Size and Distribution." In ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53198.
Abstract:
Despite major advances in treatment of coronary heart disease, apparently healthy patients die suddenly. Rupture of vulnerable fibroatheroma plaques in coronary arteries cause more than 250,000 deaths a year, yet the mechanisms as to why some caps rupture and some others do not, remain unknown. The current criterion to consider a fibroatheroma as “vulnerable” or prone to rupture is the thickness of its fibrous cap. However, available screening techniques and the cap thickness criterion have been shown to be insufficient to identify the victims before the event occurs.
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Pei, Yuanjin, and Song Wang. "Study on Head Injury Criterion affected by the various rupture mode of window shield." In 2020 7th International Conference on Information Science and Control Engineering (ICISCE). IEEE, 2020. http://dx.doi.org/10.1109/icisce50968.2020.00274.
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Washington, Christopher B., Judy Shum, Satish C. Muluk, and Ender A. Finol. "Abdominal Aortic Aneurysm Growth: The Association of Aortic Wall Mechanics and Geometry." In ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-53977.
Abstract:
In an effort to prevent rupture, patients with known AAA undergo periodic abdominal ultrasound or CT scan surveillance. When the aneurysm grows to a diameter of 5.0–5.5 cm or is shown to expand at a rate greater than 1 cm/yr, elective operative repair is undertaken. While this strategy certainly prevents a number of potentially catastrophic ruptures, AAA rupture can occur at sizes less than 5 cm. From a biomechanical standpoint, aneurysm rupture occurs when wall stress exceeds wall strength. By using non-invasive techniques, such as finite element analysis (FEA), wall stress can be estimated for patient specific AAA models, which can perhaps more carefully predict the rupture potential of a given aneurysm, regardless of size. FEA is a computational method that can be used to evaluate complicated structures such as aneurysms. To this end, it was reported earlier that AAA peak wall stress provides a better assessment of rupture risk than the commonly used maximum diameter criterion [1]. What has yet to be examined, however, is the relationship between wall stress and AAA geometry during aneurysm growth. Such finding has the potential for providing individualized predictions of AAA rupture potential during patient surveillance. The purpose of this study is to estimate peak wall stress for an AAA under surveillance and evaluate its potential correlation with geometric features characteristic of the aneurysm’s morphology.
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Varble, Nicole, Gabriel Trylesinski, Jianping Xiang, and Hui Meng. "Vortex Dynamics of Ruptured and Unruptured Intracranial Aneurysms." In ASME 2014 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/detc2014-35713.
Abstract:
Intracranial aneurysms are a potentially devastating pathological dilation of brain arteries that affect 1–5 % of the population. In this study we investigated the vortex structures of both unruptured and ruptured intracranial aneurysms as a discriminating property. We performed pulsatile computational fluid dynamic simulations on 204 patient-specific aneurysm models (57 ruptured and 147 unruptured) derived from patient angiographic imaging. Using Q-criterion we analyzed the coherent structures both throughout the aneurysm volume and at the wall. The relative surface area with positive Q values (indicating vortices at the wall) was able to differentiate ruptured and unruptured aneurysms. For the first time, in a large patient cohort, mechanistic fluid analysis is leading to insights into rupture pathways.
Reports on the topic "Rupture criterion":
1
Ren, W. Investigation on Stress-Rupture Behavior of a Chopped-Glass-Fiber Composite for Automotive Durability Design Criteria. Office of Scientific and Technical Information (OSTI), August 2001. http://dx.doi.org/10.2172/788350.
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Lublin, A., H. Ly, E. Porter, S. Mor, Y. Farnoushi, and S. M. Goyal. Novel vaccination strategies to combat chicken arthritis/tenosynovitis reoviruses in US and Israel. Israel: United States-Israel Binational Agricultural Research and Development Fund, 2020. http://dx.doi.org/10.32747/2020.8134154.bard.
Abstract:
Objectives: The general objective of the research was to study the evolution of lameness/tendon rupture-associated CARVs (chicken avian reovirus) in the US and Israel with a view to develop novel vaccines for its control. -- Specific aims: 1. To perform comparative genomic analysis and phylodynamics of CARV strains from the US and Israel, to determine space-time distribution of variant viruses; to propose unified criteria for assigning them to genotypes and genotype constellations, to determine re-assortments and rate of substitutions in the re-emerging viruses, and to identify specific strains suitable to be used for a safe and effective vaccine for the control of multiple contemporary CARV strains. 2. To develop a live virus vectored bivalent vaccine and a bivalent subunit vaccine against new CARV strains in US and Israel.
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Shim, D. J., Gery Wilkowski, Mohammed Uddin, Sureshkumar Kalyanam, and P. Mincer. PR-276-094509-R01 Develop Fracture Initiation Criteria for High-Strength Steel Line Pipe Phase II. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), August 2013. http://dx.doi.org/10.55274/r0010072.
Abstract:
This report summarizes the major findings from a PRCI Project on developing fracture initiation criteria for axial flaws (both through-wall and surface flaws) in high-strength line-pipe materials. This work was originally done on the basis to see if improvements were needed for higher-grade steels, but interestingly there were several outcomes that affect predictions for all piping steels. One of the outcomes of this work is a new correlation between Charpy USE and J-R curve for high-strength materials. Although it is based on limited data, it was demonstrated that there is significant difference compared to the existing correlation. Another interesting finding is the effect of the internal patch on burst pressure of axial through-wall-cracked pipe test. Careful experimental and detailed finite element analyses showed patching affects burst pressure by at least 10-percent which affects the leak-rupture boundary. For axial surface-cracked pipes, the effect of crack shape on the crack-driving force was investigated. Finally, it was demonstrated that the actual axial surface-cracked pipe bulging factor is considerably lower than bulging factor empirically derived at Battelle in the 1970s. If past bulging factor is used for subcritical crack growth (e.g., for SCC or fatigue analyses), the crack growth and start of ductile tearing can be significantly overpredicted. Overall, J-T analysis provided the most accurate results when proper crack-driving forces and J-R curves were used (both for axial through-wall-cracked pipe and axial surface-cracked pipe). This report also includes recommendations for future work.
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PR-313-113603-R01 Criteria For Susceptibility To Circumferential SCC. Chantilly, Virginia: Pipeline Research Council International, Inc. (PRCI), November 2013. http://dx.doi.org/10.55274/r0010805.
Abstract:
While much more rare than axial stress-corrosion cracking (SCC), circumferential SCC (CSCC) has been observed in Canada, the United States, and two European countries. Because the orientation of stress-corrosion cracks invariably is perpendicular to the maximum tensile stress, the axial stresses at the locations of the cracks must have been greater than the hoop stress. The Poisson effect and thermal effects can account for about half of the axial stresses. Evidence from the field suggests that there are three probable sources of additional axial stresses that can promote CSCC: residual stresses in bent pipe, axial stresses caused by movement of unstable soil on slopes, and residual stresses opposite rock dents. CSCC can be managed by one or a combination of the following procedures: direct assessment (DA), in-line inspection (ILI), or hydrostatic testing. Guidance for selection of sites for DA is derived from industry experience, which was determined from responses to a questionnaire and from published reports. The capabilities of ILI to detect circumferential stress-corrosion cracks or the conditions that promote them are summarized. A method for calculating the size of circumferential flaws that can cause ruptures is presented and compared with service experience. That information can provide useful guidance for ILI requirements and decisions about which flaws need to be removed immediately. The benefits and limitations of hydrostatic testing also are described.