Academic literature on the topic 'Brittle curve'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Brittle curve.'
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.
Journal articles on the topic "Brittle curve"
1
Lee, Tae-kyung, Seokmin Hong, Jongmin Kim, Min-Chul Kim, and Jae-il Jang. "Evaluation of Transition Temperature in Reactor Pressure Vessel Steels 6using the Fracture Energy Transition Curve from a Small Punch Test." Korean Journal of Metals and Materials 58, no. 8 (August 5, 2020): 522–32. http://dx.doi.org/10.3365/kjmm.2020.58.8.522.
Full textAbstract:
The small punch (SP) test is one of the small specimen test techniques, and standardization of the SP test method for evaluating the mechanical properties of metallic materials is in progress. In this study, the impact transition temperature of reactor pressure vessel steels (RPV) in nuclear power plants was estimated using the draft standard SP test method. The SP fracture energy (ESP) and normalized SP fracture energy (ENSP) of the RPV steels were evaluated at various temperatures, and their transition curves were derived and compared to the transition curve in the Charpy V notch (CVN) test. The SP transition region appeared at a much lower temperature range than that of the CVN owing to the size and notch effect. Ductile brittle transition temperature (DBTT) in the SP transition curve showed a linear relationship with DBTT and T41J in the CVN transition curve. The ductile to brittle transition behaviors of SP specimens were analyzed using fractographs and compared with the transition curves in ESP and ENSP. ENSP started to decrease at the temperature at which the SP ductile to brittle transition behavior occurred, and this means that the ENSP transition curves were in good agreement with transition behavior in the SP test. However, the ESP transition curves did not match transition behavior. Using DBTT in the ENSP transition curve is appropriate to estimate the CVNDBTT and T41J.
2
Sakai, M., S. Shimizu, and T. Ishikawa. "The Indentation Load-depth Curve of Ceramics." Journal of Materials Research 14, no. 4 (April 1999): 1471–84. http://dx.doi.org/10.1557/jmr.1999.0198.
Full textAbstract:
The pyramidal indentation-induced surface deformation of brittle ceramics is examined on the basis of extensive test results for indentation load (P)-depth (h) curves during loading/unloading cycle. A mechanically stiff test system is essential for obtaining P-h curves acceptable and reliable for subsequent analyses. Both the loading and unloading P-h curves are expressed by quadratic functions within experimental variations for all the indenters used (Vickers, Berkovich, and Knoop). The loading curve is then related to the Meyer hardness and the unloading curve to Young's modulus by the use of semiempirical equations which enable one to estimate these moduli from the observed loading/unloading parameters. An elastoplastic constitutive equation for indentation surface deformation is theoretically derived. This equation not only predicts well the experimental observations but also gains an important physical insight into the Meyer hardness. The Meyer hardness of brittle materials is not a measure for plasticity, but an elastic/plastic parameter which significantly depends on the geometry of indenter. The concept and experimental determination of “true” hardness as a characteristic material measure for plasticity are proposed.
3
Ouyang, Chengsheng, and Surendra P. Shah. "Geometry-Dependent R-Curve for Quasi-Brittle Materials." Journal of the American Ceramic Society 74, no. 11 (November 1991): 2831–36. http://dx.doi.org/10.1111/j.1151-2916.1991.tb06851.x.
Full text
4
Lambrigger, M. "Master curve for brittle cleavage fracture toughness testing." Engineering Fracture Mechanics 55, no. 4 (November 1996): 677–78. http://dx.doi.org/10.1016/0013-7944(95)00259-6.
Full text
5
Cao, L. W., S. J. Wu, and P. E. J. Flewitt. "Comparison of ductile-to-brittle transition curve fitting approaches." International Journal of Pressure Vessels and Piping 93-94 (May 2012): 12–16. http://dx.doi.org/10.1016/j.ijpvp.2012.02.001.
Full text
6
Wei, Jing Ping, Zhi Hao Ding, and Fan Chen. "Research on Brittleness and its Definition of Mudstone." Applied Mechanics and Materials 275-277 (January 2013): 379–82. http://dx.doi.org/10.4028/www.scientific.net/amm.275-277.379.
Full textAbstract:
Abstract. Through the uniaxial compressive test, the mechanical parameters and the complete stress-strain curves were obtained, which presented a brittle failure of the mudstone samples of the No.21coal seam in West Henan. Soft rock was regarded as no brittle in its failure usually, but in fact it was exactly. It showed that yield failure occurred in some areas and tension occurred inside the specimens because of the samples’ inhomogeneous deformation. The comprehensive decision method of mining surrounding rock’s brittleness was suggested: the brittleness index was more than 25; the strain of rock at failure was less than 3%, and there was brittle stress drop in the complete stress-strain curve.
7
Wallin, Kim. "The master curve method: a new concept for brittle fracture." International Journal of Materials and Product Technology 14, no. 2/3/4 (1999): 342. http://dx.doi.org/10.1504/ijmpt.1999.036276.
Full text
8
Chai, Peng, Shujuan Li, Yan Li, Lie Liang, and Xincheng Yin. "Mechanical Behavior Investigation of 4H-SiC Single Crystal at the Micro–Nano Scale." Micromachines 11, no. 1 (January 17, 2020): 102. http://dx.doi.org/10.3390/mi11010102.
Full textAbstract:
In this paper, theoretical models of the critical indentation depth and critical force on brittle materials using cleavage strength and contact theory are proposed. A Berkovich indenter is adopted for nanoindentation tests on a 4H-SiC single crystal sample to evaluate its mechanical behaviors. The stages of brittle material deformation (elastic, plastic, and brittle) can be characterized by the load versus indentation depth curves through the nanoindentation test. The curve of the elastic deformation stage follows the Hertz contact theory, and plastic deformation occurs at an indentation depth of up to 10 nm. The mechanism of 4H-SiC single crystal cracking is discussed, and the critical indentation depth and critical force for the plastic–brittle transition are obtained through the occurrence of the pop-in point. This shows that the theoretical results have good coherence with the test results. Both the values of the elastic modulus and hardness decrease as the crack length increases. In order to obtain more accurate mechanical property values in the nanoindentation test for brittle materials such as SiC, GaN, and sapphire, an appropriate load that avoids surface cracks should be adopted.
9
Barinov, S. M., and M. Sakai. "The work-of-fracture of brittle materials: Principle, determination, and applications." Journal of Materials Research 9, no. 6 (June 1994): 1412–25. http://dx.doi.org/10.1557/jmr.1994.1412.
Full textAbstract:
Theoretical and empirical considerations of the work-of-fracture, γwof, of brittle materials are reviewed. The energy principle of the work-of-fracture provides a modified Irwin similarity relationship in the nonlinear fracture mechanics regime. Various microscopic deformation and fracture processes in the crack wake and the crack-face contact regions contribute to the rising R-curve behavior of brittle materials, and then significantly affect the work-of-fracture, resulting in the work-of-fracture that is dependent on the dimension and geometry of test specimens as well as test methods. The requisite for the work-of-fracture to be a material characteristic resistance to failure is discussed in relation to the R-curve behavior. Some examples of the work-of-fracture test results demonstrate the usefulness of the work-of-fracture for designing brittle materials with improved toughness.
10
Li, Fei, Shuang You, Hongguang Ji, and Hao Wang. "Study of Damage Constitutive Model of Brittle Rocks considering Stress Dropping Characteristics." Advances in Civil Engineering 2020 (October 26, 2020): 1–9. http://dx.doi.org/10.1155/2020/8875029.
Full textAbstract:
Deep brittle rock exhibits characteristics of rapid stress dropping rate and large stress dropping degree after peak failure. To simulate the whole process of deformation and failure of the deep brittle rock under load, the Lemaitre strain equivalent theory is modified to make the damaged part of the rock has residual stress. Based on the damage constitutive model considering residual strength characteristics, a correction factor reflecting stress dropping rate is added, the Weibull distribution is used to describe the inhomogeneity of rock materials, and Drucker–Prager criterion is used to quantitatively describe the influence of stress on damage; a damage constitutive model of deep brittle rock considering stress dropping characteristics is established. According to the geometric features of the rock stress-strain curve, the theoretical expressions of model parameters are derived. To verify the rationality of the model, triaxial compression experiments of deep brittle rock under different confining pressures are conducted. And the influence of model parameters on rock mechanical behaviour is analysed. The results show that the model reflects the stress dropping characteristics of deep brittle rock and the theoretical curve is in good agreement with the experimental results, which indicates that the proposed constitutive model is scientific and feasible.
Dissertations / Theses on the topic "Brittle curve"
1
Dourado, Nuno Miguel. "R-Curve behaviour and size effect of a quasibrittle material : wood." Thesis, Bordeaux 1, 2008. http://www.theses.fr/2008BOR13734/document.
Full textAbstract:
Ce travail concerne des expériences mécaniques, des analyses numériques et des modélisations analytiques de la rupture cohésives (Mode I), vis-à-vis de l’étude du comportement mis en évidence par la courbe de Résistance (Courbe-R) et l’effet d’échelle de structures entaillées en bois massif. Des expériences de fissuration sont combinées à des analyses numériques pour déterminer les propriétés de rupture au moyen d’une procédure appelée Théorie de la Mécanique de la Rupture Linéaire Élastique équivalente (TMRLE), basée sur la complaisance de la structure. La courbe-R, obtenue à partir des expériences, selon une méthode de correction du poids propre, montre l’existence d’un domaine endommagé (Zone de Processus de Rupture) de taille non négligeable se développant en fond de fissure. Dans des conditions de fissuration stationnaire, ce domaine atteint une taille critique, et l’énergie nécessaire pour faire propager la fissure avec ce domaine endommagé (par unité de surface de rupture), reste constante. Le taux de libération de l’énergie de fissuration ainsi attendu, joue un rôle important en Mécanique de la Rupture, car il est possible simuler le comportement quasi-fragile du matériau en combinaison avec les autres propriétés de cohésion. La loi d’effet d’échelle de Bažant, utilisée pour prévoir l’influence de la taille sur la contrainte nominale, est estimée à partir de la réunion de deux comportements asymptotiques réalisés sur de petites tailles (Analyse limite ou RdM) et des grandes tailles. Une procédure analytique est présentée pour évaluer le comportement asymptotique additionnel exhibé par la contrainte nominale dans le régime intermédiaire, de façon plus exacte. Une validation numérique est présentée, et l’information expérimentale vient confirmer ce comportement asymptotiqueThis work concerns the mechanical testing, numerical analysis and modelling of cohesive fracture (Mode I) on the purpose to study the Resistance-curve behaviour and the size effect in wooden notched structures. The mechanical testing is combined with the numerical analysis to evaluate fracture properties by means of an equivalent LEFM approach based on the structure compliance. The Resistance-curve being revealed from the experiments, by means of a self-weight compensation method, correction puts into evidence that a non-negligible damaged domain (Fracture Process Zone) is under development in the crack front during the loading process. This being the case, among other fracture parameters issued from the Resistance-curve, the critical (asymptotic) energy release rate is determined, turning possible to use it in combination with other cohesive crack properties in the crack modelling (in Mode I). Thus, for a given geometry it is possible to monitor the critical dimension being revealed by the Fracture Process Zone (FPZ) during the crack propagation. The well known Bažant’s size effect law provides the scaling of the nominal strength through the asymptotic matching performed both on the small (Strength Theory) and on the large (LEFM) structure sizes. An analytical procedure is proposed to determine an additional asymptotic regime in the intermediate size range through a more accurate manner. Numerical validations of the proposed procedure are made and experimental data is presented revealing the scaling of the nominal strength through an envelop of values
2
Sieber, Lars. "Zur Beurteilung der Sprödbruchgefährdung gelochter Stahltragwerke aus Flussstahl." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-223593.
Full textAbstract:
Bei der Beurteilung der Sicherheit bestehender Konstruktionen aus altem Baustahl (i. A. Flussstahl) und der Entscheidung über notwendige Instandsetzungs- und Verstärkungsmaßnahmen ist der Nachweis ausreichender Werkstoffzähigkeit (der Sicherheit gegen ein sprödes Versagen) von wesentlicher Bedeutung. Die in DIN EN 1993-1-10 normativ geregelten Nachweismethoden zur Beurteilung der Sprödbruchgefährdung wurden basierend auf umfangreichen bruchmechanischen Untersuchungen entwickelt. Sie gelten für Schweißkonstruktionen und „Stähle aus neuerer Zeit“ mit in der Regel hohen Zähigkeitswerten. Die Quantifizierung der Zähigkeit in Werkstoffnormen erfolgt durch Kerbschlagbiegeversuche. Die Beziehung zwischen der Übergangstemperatur der Kerbschlagarbeit und der Referenztemperatur der Bruchzähigkeit wird durch die modifizierte Sanz-Korrelation hergestellt, die nur für diese Stähle abgeleitet wurde. Das in der Norm verankerte Verfahren ist für alte Flussstahlkonstruktionen mit Lochschwächung durch Niet- und Schraubenverbindungen nicht geeignet. Einerseits unterscheiden sich Kerbwirkung und Eigenspannungszustand von geschweißten und genieteten Konstruktionen und damit die Zähigkeitsanforderungen wesentlich voneinander. Auf der anderen Seite unterliegen die Zähigkeitseigenschaften von Flussstählen deutlich größeren Streuungen.
In der vorliegenden Arbeit werden experimentelle und rechnerische Untersuchungen zum Sprödbruchverhalten gelochter Konstruktionen aus altem Flussstahl vorgestellt. Wesentlicher Bestandteil sind dabei die umfangreichen Werkstoffanalysen zur Ermittlung der bruchmechanischen Werkstoffzähigkeit im spröd-duktilen Übergangsbereich nach dem Master-Curve-Konzept (ASTM E1921). Die Auswertungen belegen, dass in Abhängigkeit des Herstellungsverfahrens unterschiedliche Werkstoffgüten definiert werden können. Um den Einfluss des Stanzens von Löchern auf das Sprödbruchverhalten alter Flussstähle zu beurteilen, werden Gefügeuntersuchungen und Mikrohärtemessungen durchgeführt.
Ausgehend von einer umfassenden Analyse typischer Konstruktionsformen bestehender Tragwerke des Stahlhochbaus erfolgen bruchmechanische FE-Berechnungen an Anschlüssen von Winkelprofilen zur Bestimmung der Zähigkeitsanforderungen. Die dabei gewonnenen Ergebnisse des Spannungsintensitätsfaktors werden durch Modifikation bekannter Lösungen aus der Fachliteratur für die weitere Anwendung aufbereitet. Darauf aufbauend wird für die untersuchten Konstruktionsdetails im Rahmen einer bruchmechanischen Sicherheitsanalyse ein praxisgerechtes Verfahren zur Beurteilung der Sprödbruchgefährdung genieteter und geschraubter Bauteile abgeleitet. Mit Hilfe statistischer Methoden werden Streuungen der Festigkeits- und Zähigkeitskennwerte der Flussstähle erfasst und nach der Verifizierung durch Bauteilversuche in ein semi-probabilistisches Nachweiskonzept überführt.
3
Huapaya, Velarde Karla Priscila, and Ayvar Pool David Palomino. "Propuesta de mapa de riesgo sísmico para la estimación de pérdidas mediante curvas de fragilidad de sistemas estructurales típicos usando la metodología fema-hazus para el distrito de Surquillo en Lima." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2021. http://hdl.handle.net/10757/654669.
Full textAbstract:
Se sabe que la mayoría de las viviendas en el Perú no cumplen con las normas de edificaciones, por ello abunda la autoconstrucción debido muchas veces a las limitaciones económicas. Esto puede presentar mayor vulnerabilidad frente a algún movimiento telúrico en la costa peruana. Es necesario cuantificar el daño estructural de las edificaciones comunes producido por un sismo mediante las curvas de fragilidad.
Los métodos empleados para evaluar el riesgo sísmico generalmente son abstrusos ya que se necesita evaluar la curva de capacidad de cada vivienda seleccionada, utilizando un análisis no lineal o por desempeño sísmico; por ello en un área de mayor amplitud como en el caso de un distrito se vuelven poco convencionales para la estimación de perdidas. Por este motivo, en el presente trabajo de investigación, se emplea un método de la vulnerabilidad sísmica utilizando las curvas de fragilidad propuestas por el FEMA.
Si bien las construcciones americanas presentan características propias de lugar y la calidad de los materiales de las diferentes tipologías estructurales, se puede utilizar la metodología HAZUS pero adaptándolas a la realidad peruana.
Debido a esto, las viviendas serán analizadas en el mapa de riesgo sísmico para escenarios que comprenden las siguientes clasificaciones de intensidad del sismo: frecuente, ocasional, raro y muy raro, analizando así el comportamiento y los niveles de daño alcanzados para cada caso, con ello se podrá determinar las pérdidas para cada situación.It is known that most of the houses in Peru do not comply with the building standards, therefore self-construction abounds, often due to economic limitations. This may present greater vulnerability to any telluric movement on the Peruvian coast. It is necessary to quantify the structural damage of common buildings produced by an earthquake using the fragility curves. The methods used to evaluate the seismic risk are generally abstruse since it is necessary to evaluate the capacity curve of each selected dwelling, using a nonlinear analysis or by seismic performance; therefore, in a larger area, such as a district, they become unconventional for loss estimation. For this reason, in this research work, a seismic vulnerability method is used using the fragility curves proposed by FEMA. Although the American constructions present their own characteristics of place and the quality of the materials of the different structural typologies, the HAZUS methodology can be used but adapting them to the Peruvian reality. Due to this, the houses will be analyzed in the seismic risk map for scenarios that include the following earthquake intensity classifications: frequent, occasional, rare and very rare, thus analyzing the behavior and the levels of damage achieved for each case, with this can determine the losses for each situation.
Tesis
4
Ferreño, Blanco Diego. "Integridad estructural de vasijas nucleares en base a la curva patrón obtenida mediante probetas reconstruidas." Doctoral thesis, Universidad de Cantabria, 2008. http://hdl.handle.net/10803/10603.
Full textAbstract:
En esta tesis se ha caracterizado el acero, virgen e irradiado, de la vasija de una central nuclear española actualmente en servicio, en la región de temperaturas conocida como Zona de Transición Dúctil-Frágil. Para ello, se han ensayado probetas propias de la Mecánica de Fractura, reconstruidas a partir de mitades de probetas de impacto previamente ensayadas. Para describir la tenacidad a fractura en la Zona de Transición se ha empleado el modelo de la Curva Patrón.Finalmente, se ha analizado el impacto del procedimiento de caracterización y del modelo de la Curva Patrón sobre la Integridad Estructural de la vasija, comparando sus predicciones con las que se obtienen de aplicar los procedimientos convencionales que contempla la normativa vigente, representada por el Código ASME. En esta comparación se ha hecho uso del procedimiento FITNET de Integridad Estructural.In this thesis, the steel, virgin and irradiated, from the vessel of a Spanish Nuclear Plant currently operating, has been characterized in the range of temperatures known as Ductile to Brittle Transition Region. For this purpose, Fracture Mechanics specimens, reconstituted from halves of impact specimens previously broken, have been tested. To describe fracture toughness in the Transition Region, the Master Curve method has been used.Eventually, the influence of the characterization procedure together with the Master Curve method on the Structural Integrity of the vessel has been analyzed, comparing their predictions with those coming from applying conventional procedures proposed by the current regulations, represented by the ASME Code. In this comparison, the FITNET Structural Integrity procedure has been used.
5
Savioli, Rafael Guimarães. "Estudo experimental do comportamento à fratura frágil em aços estruturais ferríticos e aplicações à determinação da curva mestra." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3135/tde-23062016-074259/.
Full textAbstract:
Este trabalho apresenta uma investigação experimental sobre o comportamento à fratura frágil de aços estruturais ferríticos, ASTM A285 Gr C e ASTM A515 Gr 65. Os resultados deste trabalho ampliam a base de dados de propriedades mecânicas utilizadas nas análises de integridade de estruturas pressurizadas tais como vasos de pressão e tanques de armazenamento construídos com esta classe de material. O trabalho tem por objetivo também avaliar a aplicabilidade de corpos de prova de dimensões reduzidas, PCVN, na determinação da temperatura de referência, T0, por meio da metodologia da Curva Mestra, a qual define a dependência da tenacidade à fratura do material em função da temperatura. Os ensaios de tenacidade à fratura foram conduzidos utilizando-se corpos de prova solicitados em flexão três pontos com geometria SE(B), PCVN e PCVN com entalhe lateral, extraídos de chapas laminadas. Os resultados dos ensaios foram obtidos em termos de integral J no momento da instabilidade, denotados por Jc. Dados adicionais de resistência à tração e de Impacto Charpy convencional também foram obtidos para caracterizar o comportamento mecânico dos aços utilizados. Os resultados mostraram uma forte influência da geometria dos corpos de prova sobre os valores de Jc, evidenciada pela grande variação nos valores de tenacidade à fratura.This work presents an experimental investigation on the cleavage fracture behavior of structural ferritic steels, ASTM A285 Grade C and ASTM A515 Grade 65. One purpose of this study is to enlarge a previously reported work on mechanical and fracture properties for this class of steel to provide a more definite database for use in structural and defect analyses of pressurized components, including pressure vessels and storage tanks. Another purpose is to address the applicability of Precracked V-notch Charpy specimens to determine the reference temperature, T0, derived from the Master Curve Methodology which defines the dependence of fracture toughness with temperature for the tested material. Fracture toughness testing conducted on single edge bend specimens in three-point loading (SE(B), PCVN Plain Side and PCVN Side Grooved) extracted from laminated plates provides the cleavage fracture resistance data in terms of the J-integral at cleavage instability, Jc. Additional tensile and conventional Charpy tests produce further experimental data which serve to characterize the mechanical behavior of the tested materials. The results reveal a strong effect of specimen geometry on Jc values associated with large scatter in the measured values of cleavage fracture toughness.
6
Václavík, Martin. "Predikce teplotní závislosti lomové houževnatosti." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231943.
Full textAbstract:
The thesis is focused on the prediction of the fracture toughness temperature dependence through a universal curve of fracture toughness (also known as the master curve). To determine the parameters of the universal curve of fracture toughness, values acquired from the measurement results of fracture toughness and tensile tests of structural steel P91 are used. The theoretical part is based on a summary of the relevant information from the field of fracture mechanics and brittle-ductile fracture behavior of steels that are important for the understanding of fracture-strain response of materials depending on load conditions. The experimental part of the thesis contains the results from practical measurements and analyses, which were used for determining the parameters of a universal curve of fracture toughness as well as for the evaluation of fracture behavior and description of the impact of structural parameters on this behavior in case of steel P91.
7
Basu, Sandip Barsoum M. W. "On spherical nanoindentation stress-strain curves, creep and kinking nonlinear elasticity in brittle hexagonal single crystals /." Philadelphia, Pa. : Drexel University, 2008. http://hdl.handle.net/1860/2904.
Full text
8
Rasche, Stefan. "Bestimmung von Materialparametern der elastisch-plastischen Verformung und des spröden Versagens aus Small-Punch-Kleinstproben." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2013. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-116905.
Full textAbstract:
Der Small-Punch-Test (SPT) ist eine vielversprechende minimalinvasive mechanische Prüfmethode, wenn nur sehr wenig Material für Proben zur Verfügung steht. Die vorliegende Arbeit hat das Ziel, aus Small-Punch-Kleinstproben wahre Materialparameter der elastisch-plastischen Verformung und des spröden Versagens zu bestimmen. Die Kraft-Verschiebungs-Kurve des Versuchs stellt die nichtlineare Materialantwort der inhomogen beanspruchten Probe dar. Das inverse Problem der Identifikation konstitutiver Materialparameter wird numerisch mit Hilfe von Finite-Elemente-Simulationen in Verbindung mit einem Response-Surface-Modell und nichtlinearer Optimierungsverfahren gelöst, indem die Abweichung zwischen gemessener und simulierter Kurve minimiert wird. Mit Hilfe einer eigens entwickelten Kühlapparatur wurden Versuche mit ferritischen Stählen von Raumtemperatur bis hinunter zu -191°C durchgeführt und die temperaturabhängigen Fließkurven identifiziert. Bei tiefen Temperaturen wurden die Weibull-Parameter der zufällig streuenden Sprödbruchfestigkeit bestimmt und die Bruchzähigkeitsverteilung durch Simulation einer CT-Probe vorhergesagt. Für eine Aluminiumoxidkeramik wurden ebenfalls die Weibull-Parameter bestimmt sowie mit Indenterrissen versehene Proben zur Abschätzung der Bruchzähigkeit verwendetThe small punch test (SPT) is a promising minimally invasive material testing method, especially in cases where only small amounts of material are available. This thesis is aimed at identifying true material parameters of elastic-plastic deformation and brittle fracture. The load-displacement curve of the test represents the non-linear material response of the nonuniformly stressed specimen. The identification of material parameters of constitutive laws is an inverse problem, which is solved numerically. Finite element simulations together with a response surface model and nonlinear optimization techniques are applied to minimize the error between measured and simulated curves. A specially developed cooling apparatus was used to perform tests with ferritic steels from room temperature down to -191°C. The temperature dependent yield stresses and hardening curves were identified. At low temperatures the Weibull parameters of randomly distributed cleavage fracture strength were estimated. The fracture toughness distribution was then predicted by the help of a finite element simulation of a CT specimen. Furthermore the Weibull parameters of an alumina ceramic were determined and its fracture toughness was predicted using specimens prepared with indentation cracks
9
Teixeira, Juliana Cristine de Sousa. "Influência do tipo de entalhe em tubo de aço API grau X60 para obtenção da curva de temperatura de transição dúctil–frágil no ensaio de DWTT." Guaratinguetá, 2018. http://hdl.handle.net/11449/154208.
Full textAbstract:
Orientador: Marcelo dos Santos PereiraResumo: O ensaio de queda de peso DWTT (Drop Weigth Tear Test) é um método amplamente utilizado pela indústria de óleo e gás para determinar a capacidade de um material em impedir a propagação de uma trinca. Esse método foi desenvolvido pelo Battelle Memorial Institute, e é realizado em conformidade com a especificação API RP 5L3 "Práticas Recomendadas para a Condução de Testes de Queda de Peso". Com o desenvolvimento dos aços ARBL, o comportamento dos aços vem mostrando algumas particularidades resultantes do processamento termomecânico, e por esse motivo, podem não apresentar o mesmo comportamento à fratura que aços mais antigos, como delaminações ou inclusões não metálicas. Atualmente são propostos dois tipos de entalhe, sendo o tipo prensado, obtido pela estampagem de uma matriz na amostra, e o tipo Chevron, que deve ser usinado. A correlação entre ambos os entalhes pode ser realizada apenas para a análise da porcentagem da superfície dúctil da fratura. Outros tipos de correlação como energia absorvida para impacto, não são recomendados, uma vez que a concentração de tensão para o entalhe Chevron é muito maior, facilitando o rompimento da amostra, enquanto que o entalhe prensado demanda maior energia, uma vez que possui maior encruamento na região. No presente trabalho foram realizados os levantamentos de curvas de temperatura de transição dúctil e frágil (TTDF) do material base do tubo com dimensões de 762 mm x 38,1 mm de aço carbono com grau API X60, através da análise da porce... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The Drop Weigth Tear Test (DWTT) is a method widely used by the oil and gas industry to determine the ability of a material to prevent the propagation of a crack. This method was developed by the Battelle Memorial Institute, and is performed in accordance with API RP 5L3 "Drop-Weight Tear Tests on Line Pipe" specification. With the development of ARBL steels, the behavior of steels has shown some particularities resulting from thermomechanical processing, and for this reason, they may not present the same fracture behavior as older steels, such as delamination or nonmetallic inclusions. Currently two types of notch are proposed, being the type pressed, obtained by the stamping of a matrix in the sample, and the type Chevron, that must be machined. The correlation between both notches can be performed only for the analysis of the percentage of the ductile surface of the fracture. Other types of correlation as energy absorbed for impact are not recommended, since the stress concentration for the Chevron notch is higher, facilitating the rupture of the sample, while the notched press demands greater energy, since it has greater hardening in the region. In the present study, the ductile and brittle transition temperature (TTDF) curves of the base material of the pipe with dimensions of 762 mm x 38.1 mm of carbon steel with API grade X60 were carried out, through the analysis of the percentage of ductile fracture resulting whose results were shown to be equivalent for both notch: ... (Complete abstract click electronic access below)
Mestre
10
Haskel, Hudison Loch. "Avaliação da tenacidade à fratura e do efeito da microtextura e mesotextura na curva de transição dúctil frágil do aço API 5L X70." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2013. http://tede2.uepg.br/jspui/handle/prefix/1426.
Full textAbstract:
Made available in DSpace on 2017-07-21T20:42:39Z (GMT). No. of bitstreams: 1
Hudison.pdf: 7678712 bytes, checksum: 77d524c573ba60402f77fbda4e17c5e9 (MD5)
Previous issue date: 2013-03-25Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
In the present study was investigated the API 5L X70 steel mechanical behavior through tensile and instrumented impact tests. Results from the instrumented Charpy impact test have allowed quantify the forces, energies and deflections of the specimens. It was used to obtain the fracture mechanics parameters such as the dynamic fracture toughness JId, the stress intensity factor for dynamic loading KId, as also range the ductile brittle transition temperature. Simultaneously was evaluated the mechanisms that induce to the delamination phenomenon as well as the investigation of their influence on the absorbed energy during the impact test. It was also analyzed the microtexture and mesotexture of different samples from the brittle, ductile and mixed regions from the ductile brittle transition temperature curve. Results have shown that the longitudinal direction was slightly superior mechanical properties when compared to the transverse direction. The dynamic fracture toughness JId was higher for the L-T specimen orientation when compared to the T-L orientation and it tends to increase with increasing temperature for both directions. The stress intensity factor values for dynamic loading was close to in both L-T and T-L orientations. The microtexture has revealed that deformation process from the impact test preserves some of its characteristics from the prior processing such as phase transformations and recrystallization components. While the mesotexture feature has shown higher energy values in the ductile brittle transition temperature curve, it is resulted from the formation of deformation substructure. Results obtained by scanning electron microscopy and light microscopy have shown that the main factors that may be contributing to the formation of crack-divider type delaminations are banded microstructure and elongated ferrite grains. While the microtexture from the edges delamination has shown that propagation mechanism is intergranular. Taylor factor mapping has shown that the mechanism responsible for the formation of delamination is accompanied by low plastic deformation.
No presente trabalho foi investigado o comportamento mecânico do aço API 5L X70 através de ensaios de tração e impacto instrumentado. O ensaio de impacto Charpy instrumentado permitiu quantificar as forças, energias e deflexões dos corpos de prova. Com a utilização destes dados foram obtidos parâmetros da mecânica da fratura, tais como, a tenacidade à fratura dinâmica JId, o fator de intensidade de tensão para carregamento dinâmico KId, além da faixa de valores da temperatura de transição dúctil frágil. Concomitantemente foram avaliados os mecanismos que contribuem na formação do fenômeno conhecido como delaminação, bem como a investigação de sua influência sobre a energia absorvida durante o ensaio de impacto. Foram também analisadas a microtextura e mesotextura de diferentes amostras retiradas da região frágil, dúctil e mista, da curva de transição dúctil frágil do material. Os resultados mostraram que o material possui propriedades mecânicas de impacto ligeiramente superiores na direção longitudinal à laminação comparado à direção transversal. Os valores encontrados para a tenacidade à fratura dinâmica JId são superiores para corpos de prova com orientação L-T quando comparados para a orientação T-L, e tendem a aumentar com o aumento da temperatura para ambas orientações. Os valores encontrados para o fator de intensidade de tensão para carregamento dinâmico foram próximos para ambas as orientações L-T e T-L. A microtextura revelou que após a deformação no ensaio de impacto o aço preserva algumas das características do seu histórico de processamento tais como componentes de transformações de fase e recristalização. Enquanto que o estudo da mesotextura mostrou que maiores valores de energia na curva de transição dúctil frágil resultam na formação de uma subestrutura de deformação. Resultados obtidos por microscopia eletrônica de varredura e microscopia ótica mostraram que os principais fatores que podem estar contribuindo para formação de delaminações do tipo trinca divisora são a microestrutura bandeada e grãos alongados de ferrita. Enquanto que a microtextura nas bordas da delaminação mostrou que o seu mecanismo de propagação é intergranular. O mapeamento do fator de Taylor mostrou que o mecanismo responsável pela formação da delaminação é acompanhado por pouca deformação plástica.
Book chapters on the topic "Brittle curve"
1
Mai, Yiu-Wing. "Failure Characterisation of Fibre—Reinforced Cement Composites with R—Curve Characteristics." In Toughening Mechanisms in Quasi-Brittle Materials, 467–505. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3388-3_30.
Full text
2
Carpinteri, Alberto. "Size-scale transition from ductile to brittle failure: structural response vs. crack growth resistance curve." In Current Trends in Concrete Fracture Research, 175–86. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3638-9_12.
Full text
3
Rebelo, Carlos A. C. C., António Torres Marques, and Paulo M. S. T. De Castro. "The Influence of Cure Conditions on the Fracture of Non-reinforced Thermosetting Resins." In Brittle Matrix Composites 1, 305–9. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4319-3_19.
Full text
4
Herrmann, K. P., and F. Ferber. "Curved Thermal Crack Growth in Self-Stressed Models of Fibre Reinforced Materials with a Brittle Matrix." In Brittle Matrix Composites 1, 49–68. Dordrecht: Springer Netherlands, 1986. http://dx.doi.org/10.1007/978-94-009-4319-3_3.
Full text
5
Bennison, Stephen J., Jürgen Rödel, Srinivasarao Lathabai, Prapaipan Chantikul, and Brian R. Lawn. "Microstructure, Toughness Curves and Mechanical Properties of Alumina Ceramics." In Toughening Mechanisms in Quasi-Brittle Materials, 209–33. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-011-3388-3_13.
Full text
6
Qasim, Tarek, Chris Ford, Mark Bush, and Xiao Zhi Hu. "Contact Damage in Brittle Curved Coatings: The Influence of Indenter/Coating Modulus Mismatches." In Fracture of Materials: Moving Forwards, 369–74. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-994-6.369.
Full text
7
Lambrigger, M. "Ductile-To-Brittle Transition of 9-11wt.%Cr Ferritic-Martensitic Steels in Terms of Dynamic Weibull Master Curves." In Steels and Materials for Power Plants, 134–37. Weinheim, FRG: Wiley-VCH Verlag GmbH & Co. KGaA, 2006. http://dx.doi.org/10.1002/3527606181.ch23.
Full text
8
Park, Mincheol, Heuisoo Han, and Yoonhwa Jin. "Integrated Analysis Method for Stability Analysis and Maintenance of Cut-Slope in Urban." In Slope Engineering. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.94252.
Full textAbstract:
In the process of constructing roads for the development of the city, cut-slopes are made by excavating mountains. However, these cut-slopes are degraded in strength by time-deterioration phenomenon, and progressive slope failure is caused. This study developed an integrated analysis method for stability analysis and maintenance of cut-slopes in urban. The slope stability analysis was performed using the finite element model, and the progressive slope failure by time-dependent deterioration was quantified by using the strength parameters of soil applying the strength reduction factor (SRF). The displacements until the slope failure by slope stability analysis were quantified by cumulative displacement curve, velocity curve, and inverse velocity curve and, applied to the slope maintenance method. The inverse-velocity curve applied to the prediction of the time of slope failure was regressed to the 1st linear equation in the brittle material and the 3rd polynomial equation in the ductile material. This is consistent with the proposed formula of Fukuzono and also shows similar behavior to the failure case in literature. In the future, integrated analysis method should be improved through additional research. And it should be applied to cut-slope to prevent disasters.
9
FIGIEL, Ł., and M. KAMIŃSKI. "FATIGUE SENSITIVITY ANALYSIS FOR THE CURVED LAYERED COMPOSITE BEAM." In Brittle Matrix Composites 7, 477–84. Elsevier, 2003. http://dx.doi.org/10.1533/9780857093103.477.
Full text
10
Veselý, Vàclav, and Zbyněk Keršner. "R -curves from Equivalent Elastic Crack Approach: Effect of Structural Geometry on Fracture Behaviour." In Brittle Matrix Composites 8, 527–36. Elsevier, 2006. http://dx.doi.org/10.1533/9780857093080.527.
Full textConference papers on the topic "Brittle curve"
1
Sham, T. L., Samer H. Mahmoud, Heshan P. Gunawardane, and Rami A. Hawileh. "Flaw Evaluations Using Master Curve Methodology." In ASME 2007 Pressure Vessels and Piping Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/pvp2007-26648.
Full textAbstract:
The Master Curve (MC) reference temperature, T0, characterizes the fracture performance of pressure vessel steels in the ductile-brittle transition region. An MC-based flaw-evaluation analysis procedure that accounts for the variations of stress intensity factor, temperature, constraint, and material conditions is presented. The analysis procedure is applied to an example problem of pressure-temperature curve construction for a Section XI, Appendix G, internal, axial, semi-elliptical surface flaw subjected to a simple cool-down transient. The results show that the enhancement in the fracture toughness due to constraint loss in the ductile-brittle transition region as seen in data from test specimen geometries does not always translate to similar benefits in structural applications. Analyses such as those carried out in this work are necessary to quantify the potential benefit for each application.
2
Gui, Lele, Tong Xu, Binan Shou, and Haiyang Yu. "Estimation of Q345R Fracture Toughness Based on Master Curve." In ASME 2017 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/pvp2017-65484.
Full textAbstract:
1T CT specimens are used to evaluate the fracture toughness of Chinese Q345R steel in the ductile-brittle transition regime by Master Curve method. Tensile tests, Charpy impact tests and drop-weight tests of Q345R steel are also carried out to get the ductile-brittleness transition temperature and nil-ductility transition temperature. Master Curves are compared with the empirical formulas adopted in ASME, API and BS codes. Results show that the reference temperature T0 values derived from single-temperature and multi-temperature method by 1T specimen are basically consistent. Master Curve can well envelop the fracture toughness and temperature curves derived from the empirical formulas, and is more economic and flexible than the K1C curve with sufficient conservation.
3
Noronha, Silvester J., and Heshan P. Gunawardane. "A Dislocation Simulation Approach to Physical Basis of Master Curve." In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61059.
Full textAbstract:
Discrete dislocation simulations of crack-tip plasticity are used to study the sharp increase in fracture toughness around ductile-brittle transition temperature of ferritic steels. The model used composed of a macrocrack with a microcrack ahead of it in its crack plane. The microcrack represents potential fracture sites at internal inhomogenities, such as brittle precipitates. The simulation has two stages: at first the fracture stress of microcrack, σF is calculated from dislocation simulation of microcrack-tip plasticity. In the next stage the fracture toughness is estimated by the macrocrack tip plasticity simulation; the fracture toughness is applied stress intensity at the macrorack when the tensile stress at the microcrack position attains σF. The brittle-ductile transition curve is obtained by determining the fracture toughness at various temperatures. Factors that contribute to the sharp upturn in fracture toughness with increasing temperature are found to be the increase in dislocation mobility, the decrease in tensile stress ahead of the macrocrack tip due to blunting and increase in mircocrack fracture stress due to increase in plasticity at the microcrack tips. The shape of the curve obtained is similar to the Master Curve.
4
Lindqvist, Sebastian, and Kim Wallin. "Master Curve Procedure Accounting for the Combined, Constraint, Ductile Tearing and Loading Rate Effects." In ASME 2019 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/pvp2019-93844.
Full textAbstract:
Abstract The probability of brittle fracture is affected, aside from the crack driving force, by changes in constraint, loading rate and crack propagation due to an increase in the sampling volume. In addition, crack propagation, per se, can lead to constraint changes and it also affects the effective strain rate at the crack tip. Especially in the case of leak before break (LBB) where a surface crack transforms instantaneously to a through-wall crack, the increase in local strain rate combined with constraint change and ductile crack extension can be sufficient to cause a transition from ductile fracture to brittle fracture. This, and other similar events, require the development of an advanced Master Curve procedure to account for combined effect of constraint, ductile tearing and loading rate on the brittle fracture probability. A simplified methodology for achieving this is outlined and demonstrated here.
5
Miura, Naoki, Naoki Soneda, Shu Sawai, and Shinsuke Sakai. "Proposal of Rational Determination of Fracture Toughness Lower-Bound Curves by Master Curve Approach." In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77360.
Full textAbstract:
The Master Curve gives the relation between the median of fracture toughness and temperature in ductile-brittle transition temperature region. The procedure to determine the Master Curve is provided in the current ASTM E1921 standard. Considering the substitution of the alternative lower-bound curves based on the Master Curve approach for the recursive KIc curves in the present codes, the statistical characteristic should be well incorporated into the determination of the lower-bound curves. The appendix in the ASTM standard provides the procedure to derive the lower-bound curves, however, it seems to be addressed without sufficient consideration on statistical reliability. In this study, we proposed a rational determination method of fracture toughness lower-bound curves based on the Master Curve approach. The method took account of the effect of sample size in the determination of the tolerance bound curve. The adequacy of the proposed method was then verified by comparing with a fracture toughness database for RPV steels. The method allows the application of the Master Curve using fewer specimens, which can coexist with the present surveillance program.
6
Orynyak, Igor, Maksym Zarazovskii, Anatolii Batura, Mykhaylo Borodii, and Evgen Danil’chuk. "Brittle Fracture Probabilistic Assessment of WWER-1000 RPVs." In ASME 2014 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/pvp2014-28557.
Full textAbstract:
This paper presents a methodology for brittle fracture probability assessment of WWER-1000 RPVs subjected to PTS. The main attention of the study is focused on the definition of the stochastic input data: fracture toughness, CTB, size and shape of the defects. Fracture toughness of RPV metal in the initial state is determined, separately for the base metal and the welds, as the mean curve lines of relevant experimental data. Metal embrittlement is taken into account by increasing CTB. Based on the results of the Ukrainian surveillance specimens program, a CTB database of WWER-1000 RPVs is created. As a result of processing these data, the CTB temperature dependence on the neutron fluence and chemical composition are obtained. The probability of the fracture toughness curve position on the temperature axis is defined by the CTB standard deviation in accordance with normal distribution law. The distribution laws of depth and shapes of defects are taken according to the NRC data and verified on the base of the statistics of the defects, which were found in the WWER-1000 RPVs of the Zaporozhye NPP. In fact, probabilistic calculation of the RPV brittle fracture is performed similarly to the deterministic one. Fields of temperature and stresses in different RPV zones in each timepoint of considered emergency scenario are calculated by the high-effective variant of transfer matrix method in axisymmetric elastic formulation. Semielliptical axial cracks of different sizes and proportions are conservatively considered on the inner surface of RPV. SIF along the crack front is defined using the original variant of Weight Function Method. The probability of failure of a particular defect is determined as the probability that CTB of the appropriate metal reaches the maximum allowable CTB value for the scenario. The presented method is used for the renewal of operating licenses process of Unit 2 RPV of the South Ukrainian, and Units 1 and 2 RPVs of the Zaporozhye NPPs.
7
Mayer, Uwe, Thomas Reichert, and Johannes Tlatlik. "Fracture Mechanics at Elevated Loading Rates in the Ductile to Brittle Transition Region." In ASME 2017 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/pvp2017-65358.
Full textAbstract:
The rate-dependent reference temperature T0,x characterizes the fracture toughness of ferritic steels at the onset of cleavage. Fracture toughness values KJc,d were determined according to the Annex A1 of ASTM E1921 [1] which refers to the high rate annexes A14 and A17 of ASTM E1820 [2]. Results of extensive dynamic fracture toughness experiments at various loading rates, temperatures, specimen types and sizes revealed shortcomings in the transferability of the shape of the Master Curve under quasi-static conditions to elevated loading rates. In particular, the quasi-static Master Curve predicts lower fracture toughness values towards higher temperatures than experimentally observed under dynamic loading causing a steeper Master Curve shape. Fractographic examinations proved the relevance of local crack arrest under dynamic loading conditions, which is consistent with the view of the parallelism of dynamic fracture probability and probability of arrest.
8
Wallin, Kim, Sakari Pallaspuro, Päivi Karjalainen-Roikonen, and Pasi Suikkanen. "Applicability of the Master Curve Method to Ultra High Strength Steels." In ASME 2015 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/pvp2015-45554.
Full textAbstract:
Although Ultra High Strength Steels (UHSS) with nominal strengths up to 1500 MPa have been available on the market for many years, the use of these steels in the civil engineering industry is still rather uncommon. One critical point limiting the use of UHSS steels lies in their rather poorly documented fracture properties in relation to more conventional steels covered by the codes. The major concept governing the assessment of steels is the Master Curve (MC) methodology. It provides a description for the fracture toughness scatter, size effect and temperature dependence in the ductile to brittle transition region. It enables a complete characterization of brittle fracture toughness of a material based on only a few small size specimens. The method combines a theoretical description of the scatter, a statistical size effect and an empirically found temperature dependence of fracture toughness. The fracture toughness in the brittle fracture regime is thus described with only one parameter, the transition temperature T0. At this temperature the mean fracture toughness for a 25.4 mm thick specimen is 100 MPa√m. The Master Curve method as defined in ASTM E1921-13a is applicable to ferritic structural steels with yield strength between 275 MPa and 825 MPa. Very few studies have been made with respect to the applicability of the Master Curve to Ultra High Strength Steels with yield strengths in the excess of 900 MPa. This is the topic of this work. Focusing on novel directly quenched high performance steels, the applicability of the Master Curve methodology with special emphasis on the temperature dependence will be investigated. Possible improvements to the Master Curve will be proposed for further consideration.
9
Subramanian, Kannan, Jorge Penso, Graham McVinnie, and Greg Garic. "Brittle Fracture Assessments on Offshore Piping Systems." In ASME 2013 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/pvp2013-98013.
Full textAbstract:
Offshore piping systems may be subject to low temperatures due to operation related scenarios and are cause for brittle fracture concern. The analyses included in this work consider probable events leading to low temperature conditions such as auto-refrigeration. In such circumstances, brittle fracture assessments of piping are typically carried out using API 579-1/ASME FFS-1, latest referred as API 579, procedures. The assessment of piping systems are in many cases very involved, requiring extended piping system information followed by stress analysis and MAT calculations depending on the material type, thickness of the piping analyzed, and stress levels. In addition, the component-by-component assessment approach recommended in API 579 leads to tedious calculations. In this paper, approaches used for static and dynamic low temperature scenarios are presented. Static cases involve constant pressures and temperatures. Dynamic cases involve varying pressures and temperatures as the low temperature events unfold (e.g., blowdown of a valve or a vessel). Dynamic cases warrant the requirement of a safe operating envelope or MAT curve similar to those developed for pressure vessels. Case studies involving the influence of the extent of the system analyzed and the restraint conditions on the results are also presented. In addition, the importance of separately assessing the rated components such as flanges and valves away from the stress analysis is discussed. Based on the assessments carried out, a discussion on the toughness rules defined in ASME Section VIII Divisions 1, 2, and the original piping code of construction is provided.
10
Miura, Naoki, Naoki Soneda, Taku Arai, and Kenji Dohi. "Applicability of Master Curve Method to Japanese Reactor Pressure Vessel Steels." In ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-93792.
Full textAbstract:
The Master Curve method has been proposed and recognized worldwide as an alternative approach to evaluate fracture toughness of reactor pressure vessel (RPV) steels in brittle-to-ductile transition temperature range. This method theoretically provides the confidence levels of fracture toughness in consideration of the statistical distribution, which is an inherent property of fracture toughness. In this study, a series of fracture toughness tests was conducted for typical Japanese RPV steels, SFVQ1A and SQV2A, to identify the effects of test temperature, specimen size, and loading rate, and the applicability of the Master Curve method was experimentally validated. The differences in test temperature and specimen size did not affect master curves. In contrast, increasing loading rate significantly shifted master curves to higher temperatures. The lower bound curve based on the master curve could conservatively envelop all of the experimental fracture toughness data. The present rule, in which the lower limit of fracture toughness is indirectly determined by Charpy impact test results, can be too conservative, while the application of the Master Curve method may significantly reduce the conservativity of the allowable level of fracture toughness.