Academic literature on the topic 'Cracking intensity'
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Journal articles on the topic "Cracking intensity"
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Yang, Bin, Qin Shou Huang, Xin Wang Qiu, and Hua Xu. "Dynamic Response Analysis of Stress Intensity Factors of Reflective Cracking in Asphalt Overlay Suffer Wheel Load." Advanced Materials Research 217-218 (March 2011): 187–90. http://dx.doi.org/10.4028/www.scientific.net/amr.217-218.187.
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Partial wheel loading of the existing old cement concrete pavement joint will easily causes shear-type reflective cracking of asphalt overlay, which will cut down the service life of the pavement. This paper conducts an research on the changing rules of stress intensity factors of reflective cracking in asphalt overlay suffer dynamic loads. Choose 3 asphalt overlays with typical reflective cracking extend length of 1cm, 4cm and 8cm to investigate the impacts of parametric variation of vehicle speed, asphalt overlays thickness and modulus and stress absorbing layer on stress intensity factors of reflective cracking in asphalt overlays suffer singe-wheel dynamic loads. Results show that time history curves of dynamic stress intensity factors declines with the increase of structure-layer parameters; the maximum amplitude decreases as time goes on; the larger the structure parameter is, the faster the degradation is; and the vibration levels to gentle in the later half period, but stress intensity factors are not equal to zero in the last period of vibration, which shows that there exists residual stress intensity factors.
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Fang, Qiang. "A Comparative Study of Delayed Hydride Cracking in Zr-3.5Sn-0.8Nb-0.8Mo and Zr-2.5Nb." Materials Science Forum 917 (March 2018): 207–11. http://dx.doi.org/10.4028/www.scientific.net/msf.917.207.
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A new test procedure for measuring the resistance to delayed hydride cracking was developed. The critical stress intensity factors for delayed hydride cracking and the crack growth velocities of Zr-3.5Sn-0.8Nb-0.8Mo alloy with different heat treatments were evaluated and compared with Zr-2.5Nb. It was found that Delayed Hydride Cracking (DHC) crack growth velocity increases with the alloy strength, and the critical stress intensity factor is independent of heat treatment history or alloy composition.
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Sun, Jiamin, Jonas Hensel, Thomas Nitschke-Pagel, and Klaus Dilger. "Influence of Restraint Conditions on Welding Residual Stresses in H-Type Cracking Test Specimens." Materials 12, no. 17 (August 23, 2019): 2700. http://dx.doi.org/10.3390/ma12172700.
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From the viewpoint of mechanics, weld cracking tends to occur if the induced tensile stress surpasses a certain value for the particular materials and the welding processes. Welding residual stresses (WRS) can be profoundly affected by the restraint conditions of the welded structures. For estimating the tendency of weld cracking, the small-scale H-type slit joints have been widely used for cracking tests. However, it is still hard to decide whether the real large-scale component can also be welded without cracking even though the tested weld cracking specimens on the laboratory scale can be welded without cracking. In this study, the intensity of restraint which quantitatively indicates how much a joint is restrained is used. The influence of restraint condition (intensity of restraint) on WRS is systematically investigated using both the numerical simulation and the experimental method. The achievement obtained in the current work is very beneficial to design effective H-type self-restrained cracking test specimens for evaluating the sensitivity of the material and the welding procedures for weld cracking in the real large-scale components.
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Sekine, Hideki, and Peter W. R. Beaumont. "Stress-Corrosion Cracking in Unidirectional GFRP Composites." Key Engineering Materials 430 (March 2010): 101–13. http://dx.doi.org/10.4028/www.scientific.net/kem.430.101.
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A micromechanical theory of macroscopic stress-corrosion cracking in unidirectional glass fiber-reinforced polymer composites is proposed. It is based on the premise that under tensile loading, the time-dependent failure of the composites is controlled by the initiation and growth of a crack from a pre-existing inherent surface flaw in a glass fiber. A physical model is constructed and an equation is derived for the macroscopic crack growth rate as a function of the apparent crack tip stress intensity factor for mode I. Emphasis is placed on the significance of the size of inherent surface flaw and the existence of matrix crack bridging in the crack wake. There exists a threshold value of the stress intensity factor below which matrix cracking does not occur. For the limiting case, where the glass fiber is free of inherent surface flaws and matrix crack bridging is negligible, the relationship between the macroscopic crack growth rate and the apparent crack tip stress intensity factor is given by a simple power law to the power of two.
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Li, Limin, Zhaoyang Guo, Longfei Ran, and Jiewen Zhang. "Study on Low-Temperature Cracking Performance of Asphalt under Heat and Light Together Conditions." Materials 13, no. 7 (March 27, 2020): 1541. http://dx.doi.org/10.3390/ma13071541.
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The low-temperature cracking performance of asphalt is considered one of the main deteriorations in asphalt pavements. However, there have been few studies on the low-temperature cracking performance of asphalt under heat and light together. Hence, the ductility test, bending beam rheometer (BBR) test, and asphalt composition analysis test are combined to investigate the low-temperature cracking performance under heat and light together based on the climatic conditions of China. The styrene–butadiene–styrene block copolymer (SBS)-modified asphalt binders were prepared with different modifier types and base asphalt in this research. The results show that the low-temperature cracking resistance of asphalt reduces under heat and light together. It is obviously reduced at the early stage, and it becomes worse with the increase of the aging time, temperature, and ultraviolet (UV) intensity. The asphalt composition has a significant impact on its low-temperature cracking performance, and the SBS modifier can improve the low-temperature cracking resistance of asphalt. The rational selection of base asphalt and modifier can improve the low-temperature cracking performance of asphalt. Under heat and light together, whether base asphalt or modified asphalt, the change trends of their ductility and component content are similar. Therefore, to improve the anti-cracking ability of the asphalt pavement, it is suggested to use the ductility of asphalt aged by heat and light together for 15 days as the evaluation index of the low-temperature cracking performance of asphalt, and asphalt should be selected according to the temperature and UV intensity of the asphalt pavement use area.
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Uzan, Jacob. "Evaluation of Fatigue Cracking." Transportation Research Record: Journal of the Transportation Research Board 1570, no. 1 (January 1997): 89–95. http://dx.doi.org/10.3141/1570-11.
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The continuous growth of damage from fatigue cracking is described as a two-stage process of crack initiation and crack propagation. The crack-initiation stage can be characterized by conventional laboratory fatigue tests. The crack-propagation stage is described using the Paris-Erdogan phenomenological law. Problems encountered in implementing the theory are presented and discussed. For the sake of simplicity, only Mode II (shearing mode of the crack tip) is used. Computations of the stress-intensity factors and of the number of load repetitions for propagating the crack are presented. The applicability of the above fracture approach is evaluated using a pavement design method that includes an additional term to represent the crack-propagation phase.
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Mackay, T. L., and B. J. Alperin. "Stress intensity factors for fatigue cracking in high-strength bolts." Engineering Fracture Mechanics 21, no. 2 (January 1985): 391–97. http://dx.doi.org/10.1016/0013-7944(85)90027-x.
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YU, G., B. JIANG, L. QIAO, Y. WANG, and W. CHU. "Threshold stress intensity for hydrogen—Induced cracking of tubular steel." Scripta Materialia 36, no. 12 (June 15, 1997): 1467–70. http://dx.doi.org/10.1016/s1359-6462(97)00037-7.
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Sura, V., and S. Mahadevan. "Modelling shattered rim cracking in railroad wheels." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 225, no. 6 (June 1, 2011): 593–604. http://dx.doi.org/10.1177/0954409711403671.
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Shattered rim cracking, propagation of a subsurface crack parallel to the tread surface, is one of the dominant railroad wheel failure types observed in North America. This crack initiation and propagation life depends on several factors, such as wheel rim thickness, wheel load, residual stresses in the rim, and the size and location of material defects in the rim. This article investigates the effect of the above-mentioned parameters on shattered rim cracking, using finite element analysis and fracture mechanics. This cracking is modelled using a three-dimensional, multiresolution, elastic–plastic finite element model of a railroad wheel. Material defects are modelled as mathematically sharp cracks. Rolling contact loading is simulated by applying the wheel load on the tread surface over a Hertzian contact area. The equivalent stress intensity factor ranges at the subsurface crack tips are estimated using uni-modal stress intensity factors obtained from the finite element analysis and a mixed-mode crack growth model. The residual stress and wheel wear effects are also included in modelling shattered rim cracking. The analysis results show that the sensitive depth below the tread surface for shattered rim cracking ranges from 19.05 to 22.23 mm, which is in good agreement with field observations. The relationship of the equivalent stress intensity factor (Δ K eq) at the crack tip to the load magnitude is observed to be approximately linear. The analysis results show that the equivalent stress intensity factor (Δ K eq) at the crack tip depends significantly on the residual stress state in the wheel. Consideration of as-manufactured residual stresses decreases the Δ K eq at the crack tip by about 40 per cent compared to that of no residual stress state, whereas consideration of service-induced residual stresses increases the Δ K eq at the crack tip by about 50 per cent compared to that of as-manufactured residual stress state. In summary, the methodology developed in this article can help to predict whether a shattered rim crack will propagate for a given set of parameters, such as load magnitude, rim thickness, crack size, crack location, and residual stress state.
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Miyajima, Tatsuya, and Mototsugu Sakai. "The fracture toughness for first matrix cracking of a unidirectionally reinforced carbon/carbon composite material." Journal of Materials Research 6, no. 11 (November 1991): 2312–17. http://dx.doi.org/10.1557/jmr.1991.2312.
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The fracture toughness for first matrix cracking of a uniaxially reinforced C-fiber/C-matrix composite is investigated using a modified controlled surface flaw method. The theoretical models for first matrix cracking of brittle matrix composites including the stress intensity and the potential energy approaches are reviewed in the light of the experimental results. The sharing of the applied load between the reinforcing fibers and the brittle matrix along with extensive crack front debonding enhance the fracture toughness for first matrix cracking.
Dissertations / Theses on the topic "Cracking intensity"
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Sun, Xiaodan. "Residual stresses, cracking and stress intensity factors for Vickers indentations in ceramics." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:71f1d3ed-8163-4487-a81e-df09d50710ed.
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Vickers hardness indentations on AI2O3 were studied comprehensively. Beneath indentation, there is a well-defined interface between the plastic zone and the elastic region and the radius of the plastic zone is close to half the indentation diagonal length. The residual stress field around the indentations has been measured by optical fluorescence microscope (FLM) scans. Yoffe's stress model predicted higher stresses than the experimental stress results. the radial crack lengths were measured by FLM scans, and the optical microscope (OM) and SEM methods for crack length measurements were found to significantly underestimate the crack lengths. Post indentation slow crack growth was found on the radial cracks were determined. The radial-median crack system was found for alumina indentations. Lateral cracks were also found for all the indentations, and their depths were close to the half diagonal lengths. the lateral cracks joined the tips of the radial cracks and had the similar growth rates to the radial cracks. The indentation parameters of SiC and 3Y-TZP indentations were also measured. Lateral cracking was observed beneath in SiC indentations but not in case of 3Y-TZP. The depth of the lateral crack of the SiC indentation was found to be close to the half diagonal length. the residual stresses and surface profiles around SiC and 3Y-TZP indentations were measured. the lateral crack lengths of the SiC determined from the surface profiles were close to the radial crack lengths. For TZP indentations, the highest volume fraction of the monoclinic zirconia phase was found near the edge of the indentations. Surface uplifts around indentations were found to have the profiles matching with distributions of the volume fraction of the monoclinic phase. A new Vickers indentation residual stress model has been presented using assumptions based on the experimental findings on alumina indentations. The main novelty of the model is that it predicts the stresses in the presence of cracking, and is therefore testable. The residual stress model has successfully predicted the stress fields around the polycrystalline alumina and SiC indentations but failed on TZP indentations because of the lack of lateral cracking and the tetragonal-to-monoclinic phase transformation. From the residual stress model, a new formula for the indentation stress intensity factor K was derived, which provided good results for threshold stress intensity factor, K10, on alumina, and fracture toughness, KIC, for SiC, and Si3N4. Three adjustable parameters can be added to strengthen existing model.
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Hassan, Tasnim. "NUMERICAL STUDY OF TRANSIENT RESPONSE OF AN INTERFACE-CRACK IN A TWO LAYERED PLATE (ANTI-PLANE, STRESS INTENSITY FACTOR)." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275474.
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Miller, Douglas Dwight. "Stress intensity factors for circumferential part-through cracks from holes in hollow cylinders subjected to tension and bending loads." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/16055.
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Pierola, Javier. "Three dimensional stress intensity factor for large arrays of radial internal surface cracks in a cylindrical pressure vessel." FIU Digital Commons, 1993. http://digitalcommons.fiu.edu/etd/2514.
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The objective of this study is to present the mode I stress intensity factor distribution (SIF) along the crack-front for a wide array of semicircular and semi-elliptical surface cracks inside of a pressurized thick-walled cylinder. A three-dimensional finite element package ANSYS is used to evaluate the SIF for multicracked cylinder with number of cracks from n=1 to 128, the ratio of crack-depth to the wall thickness a/t=0.05 to 0.6, the ellipticity of the crack (the crack-depth to the semi-crack length) a/c=0.2 to 1.5, the ratio of the outer to the inner radius ro/ ri=2.
A substructuring technique is introduced which solved a coarse model meshed with ten-node isoparametric elements and applied the resulting displacements in the boundary surface of a submodel which is built employing singular elements along the crack-front to produce the 1/√r singularity . The SIF is evaluated using nodal-displacement method.
To validate the modeling and analysis procedure of the present results various configurations were solved using this method and compared to other finite element solutions. The present results were in very good agreement: less than 5 % comparing with Raju and Newman's results and within 8 % of Kirkhope's results.
An empirical equation to calculate the maximum SIF, was developed in this study. The equation was obtained by nonlinear fitting of the finite element results and the error was within ± 5.7 %.
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Rhymer, Donald William. "Stress Intensity Solutions of Thermally Induced Cracks in a Combustor Liner Hot Spot Using Finite Element Analysis." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7515.
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Thermally cycling a thin plate of nickel-based superalloy with an intense in-plane thermal gradient, or hot spot, produces thermally induced crack growth not represented by classic thermo-mechanical fatigue (TMF). With the max hot spot temperature at 1093 C (2000 F) of a 1.5 mm thick, 82.55 mm diameter circular plate of B-1900+Hf, annular buckling and bending stresses result during each thermal cycle which drive the crack initiation and propagation. A finite element analysis (FEA) model, using ANSYS 7.1, has been developed which models the buckling and as well as represents the stress intensity at simulated crack lengths upon cool down of each thermal cycle. The model approximates the out-of-plane response at heat-up within 5% error and a difference in the final displacement of 0.185 mm after twelve thermal cycles. Using published da/dN vs. Keff data, the number of cycles needed to grow the crack to the experimental arrest distance is modeled within 1 mm. The number of cycles to this point is within 5 out of 462 in comparison to the experimental test.
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Mariano, Neide Aparecida. "Corrosão sob tensão de um aço inoxidável austenítico em soluções aquosas contendo cloretos." Universidade de São Paulo, 1997. http://www.teses.usp.br/teses/disponiveis/18/18136/tde-03102017-142025/.
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No presente trabalho foi estudado o comportamento de um aço inoxidável austenítico do sistema Fe-Cr-Mn-N, nas condições como recebido, solubilizado e sensitizado, quando submetidos à meios contendo cloretos. Para analisar a suscetibilidade à corrosão sob tensão foram utilizados corpos de prova dos tipos DCB (\"Double Cantilever Beam\") e C(T) (\"Compact- Tension\"), pré-trincados em fadiga, com entalhes laterais e carregados com cunhas. Os meios empregados foram as soluções aquosas 45% em peso de MgCl2 na temperatura de ebulição de 154°C, água do mar sintética na temperatura ambiente e de ebulição de 100°C e 3,5% em peso de NaCI na temperatura ambiente. A suscetibilidade à corrosão sob tensão foi avaliada em termos do fator limite de intensidade de tensão, KISCC, e foram caracterizados os aspectos fractográficos dos corpos de prova em que ocorreram propagação de trinca por corrosão sob tensão. Foi verificado que apenas os corpos de prova do aço E3949 nas condições como recebido e sensitizado, foram suscetíveis à corrosão sob tensão em solução aquosa de 45% em peso de MgCl2 na temperatura de ebulição. Também foi determinado o comportamento eletroquímico do material nas condições citadas acima com relação aos meios empregados. Os resultados das curvas de polarização obtidas mostraram que o material apresenta baixa resistência à corrosão, principalmente em meios de MgCl2.The present work studies the stress corrosion cracking behavior in austenitic Fe-Cr-Mn-N stainless steel, in as received, solubilized and sensitized conditions, when submited to several chlorides environments. To evalued the stress corrosion cracking susceptibility, DCB (\"Double Cantilcver Beam\") and C(T) (\"Compact- Tension\") specimens, fatigue precracked, side grooved and wedge loaded were used. The environments employed were boiling solution of 45 wt% of MgCl2 at 154ºC, synthetic sea water at room and 100°C temperatures, and a solution with 3,5 wt% of NaCI at room temperature. The susceptibility to stress corrosion cracking has been evaluated in terms of the threshold stress intensity factor, KISCC, and the fracture surface appearance of those specimens whose the crack propagation took place was characterized. The results showed that only the specimens in the as received and sensitized conditions, were suceptible to the stress corrosion cracking effect in the solution with 45 wt% of MgCl2 at the boilling temperature. Also, it has been verified the electrochemical behavior of this steel when submited in the above environments. The results of polarization curves showed that the material presents low corrosion strength, mainly in MgCl2 environments.
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Lados, Diana Aida. "Fatigue crack growth mechanisms in Al-Si-Mg alloys." Link to electronic thesis, 2004. http://www.wpi.edu/Pubs/ETD/Available/etd-0204104-125758.
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Thesis (Ph. D.)--Worcester Polytechnic Institute.Keywords: Microstructure; Elastic-Plastic Fracture Mechanics; Crack closure; A356; J-integral; Conventionally cast and SSM Al-Si-Mg alloys; Residual stress; Heat treatment; Fatigue crack growth mechanisms; Threshold stress intensity factor; Plastic zone; Paris law; Fracture toughness; Roughness. Includes bibliographical references.
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Roux-Langlois, Clément. "Simulation de fissures courbes en trois dimensions avec extraction directe des facteurs d'intensité des contraintes : En vue de l'identification de lois de propagation de fatigue." Thesis, Lyon, INSA, 2014. http://www.theses.fr/2014ISAL0112/document.
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La compréhension du comportement de structures jusqu'à leur ruine est nécessaire pour concevoir au mieux ces structures. Selon le matériau et les sollicitations considérées, les mécanismes physiques à l'origine de la rupture changent. Nous nous intéresserons à des matériaux homogènes pour lesquels la ruine passe par le développement de fissures autour desquelles les non-linéarités de comportement n'ont pas un rôle dominant. Ces conditions sont réunies pour les matériaux fragiles pour lesquels la source principale de dissipation est la génération non réversible d'une surface libre, et pour certaines fissures de fatigue. Sur un cycle de chargement, il existe de nombreuses applications pour lesquelles les non-linéarités restent confinées. La théorie de la mécanique linéaire élastique de la rupture est alors un modèle pertinent pour approcher le comportement de la structure. Sous ces hypothèses, le front de la fissure introduit une singularité. L'étude asymptotique de cette singularité dans des situations plane et anti-plane permet de définir les séries de Williams. La singularité est alors d'ordre un demi et elle est quantifiée par les facteurs d'intensité des contraintes (FIC) pour chacun des trois modes de sollicitations. En 3D, la fissure peut avoir une géométrie complexe, et aucune expression générale de la singularité n'existe. Dans cette thèse, les séries de Williams en déplacements sont utilisées et régularisées le long du front au sens des éléments finis. À partir de cette définition 3D des séries asymptotiques en pointe de fissure, une méthode d'extraction directe des FIC (DEK-FEM) est étendue au cas 3D. Le domaine est décomposé en deux domaines, raccordés en moyenne sur l'interface. Au voisinage du front, les champs mécaniques sont approchés par une troncature des champs asymptotiques. La singularité est donc traitée avec des champs adaptés, et les degrés de liberté associés sont directement les coefficients asymptotiques. Parmi ces coefficients asymptotiques, on retrouve les FIC et les T-stresses. Pour des raisons d'efficacité numérique et pour pouvoir relier l'échelle de la structure à l'échelle de la fissure, cette méthode est intégrée dans un contexte multigrilles localisées X-FEM. Ainsi nous montrons que cette approche permet une bonne évaluation des évolutions des FIC et du T-stress. Cette méthode est développée en parallèle d'une stratégie de post-traitement expérimental (mesure de champs de déplacements par corrélation d'images) basée sur les mêmes séries asymptotiques. Les images tridimensionnels d'un essai de fatigue in situ sont obtenues par micro-tomographie à rayons X et reconstruction. La corrélation et la régularisation basées sur les séries asymptotiques permettent d'obtenir la géométrie de la fissure et les FIC pour pouvoir identifier des lois de propagation de fissures 3D en fatigue. L'efficacité de cette méthode en parallèle d'une simulation DEK-FEM est illustrée en 2DIt is necessary to understand the behavior of structures up to their failure to enhance their design. The mechanisms and phenomena undergoing failure vary according to the considered material and boundary conditions. We consider homogeneous materials for which cracks propagate in a context where behavior nonlinearities are not dominants. These conditions are matched for brittle and quasi-brittle materials and for some fatigue cracks. For the former, the main source of dissipation is the crack propagation which can be seen as the generation of a new free-surface. For the later, there is many applications where, in one loading cycle, the nonlinearities remains confined around the crack tip. The linear elastic fracture mechanics theory is then a pertinent model to approximate the structure behavior. Under such hypotheses, a singularity appears in the crack tip vicinity. The Williams' series expansion is computed from the asymptotic study of plane and anti-plane states. The stress is singular at the crack tip and the order of this singularity is one out of two. The singularity amplitude is quantified by the stress intensity factors (SIF), one for each of the three loading modes. In 3D, the crack shape is potentially complex (front curvature and non-planar crack), and no general asymptotic series expansion exists. In this PhD thesis, the 2D Williams' series in displacements are used and regularized with a finite element evolution along the front. From this 3D definition of the asymptotic fields in the crack tip vicinity, a numerical method for direct estimation of the SIF (DEK-FEM) is extended to 3D. This method is based on domain decomposition, the two domains are bounded in a weak sense on their interface. In the crack tip vicinity, the mechanical fields are approximated by a truncation of the asymptotic series expansion. Therefore, appropriate fields are used to deal with the singularity, and the associated degrees of freedom are directly the asymptotic coefficients. Among these coefficients are the SIF and the T-stresses. To bridge the scales between the structure and the crack front singularity and to increase the numerical efficiency, this method is embedded in a localized X-FEM multigrids approach. The proposed method is shown to provide an accurate evaluation of the SIF and T-stresses evolution. This approach has been developed in combination of an experimental post-processing method (full field displacement measurement through image correlation) based on the same asymptotic series expansion. The 3D images can be obtained for in situ fatigue experiments by X-ray microtomography and reconstruction. The crack geometry and the SIF are then provided by image correlation and regularization based on Williams series expansion. These data can be used for identifying a 3D fatigue crack growth law. The efficiency of the method is illustrated in 2D
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Zeghloul, Abderrahim. "Comparaison de la propagation en fatigue des fissures courtes et des fissures longues." Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37619253w.
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Brundin, Carl. "Alternative energy concepts for Swedish wastewater treatment plants to meet demands of a sustainable society." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-146831.
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This report travels through multiple disciplines to seek innovative and sustainable energy solutions for wastewater treatment plants. The first subject is a report about increased global temperatures and an over-exploitation of natural resources that threatens ecosystems worldwide. The situation is urgent where the current trend is a 2°C increase of global temperatures already in 2040. Furthermore, the energy-land nexus becomes increasingly apparent where the world is going from a dependence on easily accessible fossil resources to renewables limited by land allocation. A direction of the required transition is suggested where all actors of the society must contribute to quickly construct a new carbon-neutral resource and energy system. Wastewater treatment is as required today as it is in the future, but it may move towards a more emphasized role where resource management and energy recovery will be increasingly important. This report is a master’s thesis in energy engineering with an ambition to provide some clues, with a focus on energy, to how wastewater treatment plants can be successfully integrated within the future society. A background check is conducted in the cross section between science, society, politics and wastewater treatment. Above this, a layer of technological insights is applied, from where accessible energy pathways can be identified and evaluated. A not so distant step for wastewater treatment plants would be to absorb surplus renewable electricity and store it in chemical storage mediums, since biogas is already commonly produced and many times also refined to vehicle fuel. Such extra steps could be excellent ways of improving the integration of wastewater treatment plants into the society. New and innovative electric grid-connected energy storage technologies are required when large synchronous electric generators are being replaced by ‘smaller’ wind turbines and solar cells which are intermittent (variable) by nature. A transition of the society requires energy storages, balancing of electric grids, waste-resource utilization, energy efficiency measures etcetera… This interdisciplinary approach aims to identify relevant energy technologies for wastewater treatment plants that could represent decisive steps towards sustainability.
Books on the topic "Cracking intensity"
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Pang, H. L. J. A literature review of stress intensity factor solutions fora weld toe crack in a fillet welded joint. East Kilbride: National Engineering Laboratory, 1991.
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A back face strain compliance expression for the compact tension specimen. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1998.
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S, Piascik Robert, and Langley Research Center, eds. A back face strain compliance expression for the compact tension specimen. Hampton, Va: National Aeronautics and Space Administration, Langley Research Center, 1998.
Find full textBook chapters on the topic "Cracking intensity"
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Saouma, Victor E., and M. Amin Hariri-Ardebili. "Ground Motion Intensity Measures." In Aging, Shaking, and Cracking of Infrastructures, 529–48. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-57434-5_22.
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Huang, Qinshou. "Dynamic Response Analysis of Stress Intensity Factor of Reflective Cracking in Asphalt Pavement Addition." In Lecture Notes in Civil Engineering, 373–84. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-5217-3_37.
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Casey, Dermot B., James R. Grenfell, and Gordon Airey. "3D Longitudinal and Transverse Cracking and the Influence of Non-Uniform Contact Pressure on the Stress Intensity Factors of these Cracks." In Materials and Infrastructures 1, 365–79. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119318583.ch26.
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Kim, Young Suk, Sang Bok Ahn, Kang Soo Kim, and Yong Moo Cheong. "Temperature Dependence of Threshold Stress Intensity Factor, KIH in Zr-2.5Nb Alloy and Its Effect on Temperature Limit for Delayed Hydride Cracking." In Experimental Mechanics in Nano and Biotechnology, 919–22. Stafa: Trans Tech Publications Ltd., 2006. http://dx.doi.org/10.4028/0-87849-415-4.919.
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Zhou, F., S. Hu, and X. Hu. "Using semi-analytical finite element method to evaluate stress intensity factors in pavement structure." In Pavement Cracking. CRC Press, 2008. http://dx.doi.org/10.1201/9780203882191.ch62.
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Sankararaman, Shankar, You Ling, and Sankaran Mahadevan. "Fatigue Crack Growth Analysis and Damage Prognosis in Structures." In Emerging Design Solutions in Structural Health Monitoring Systems, 207–33. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-8490-4.ch010.
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This chapter describes a computational methodology for fatigue crack growth analysis and damage prognosis in structures. This methodology is applicable to a variety structural components and systems with complicated geometry and subjected to variable amplitude multi-axial loading. Finite element analysis is used to address complicated geometry and calculate the stress intensity factors. Multi-modal stress intensity factors due to multi-axial loading conditions are combined to calculate an equivalent stress intensity factor using a characteristic plane approach. Crack growth under variable amplitude loading is modeled using a modified Paris law that includes retardation effects. During cycle-by-cycle integration of the crack growth law, a Gaussian process surrogate model is used to replace the expensive finite element analysis, thereby significantly improving computational effort. The effect of different types of uncertainty – physical variability, data uncertainty and modeling errors – on crack growth prediction is investigated. The various sources of uncertainty include, but not limited to, variability in loading conditions, material parameters, experimental data, model uncertainty, etc. Three different types of modeling errors – crack growth model error, discretization error and surrogate model error – are included in analysis. The different types of uncertainty are incorporated into the framework for calibration and crack growth prediction, and their combined effect on crack growth prediction is computed. Finally, damage prognosis is achieved by predicting the probability distribution of crack size as a function of number of load cycles, and this methodology is illustrated using a numerical example of surface cracking in a cylindrical component.
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"Cracking and Oxidative Dehydrogenation of Ethane to Ethylene: Process and Intensifi cation Options." In Industrial Catalysis and Separations, 318–59. Apple Academic Press, 2014. http://dx.doi.org/10.1201/b17114-19.
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Tsybulskyi, Vitalii. "IMPROVEMENT OF CALCULATION METHOD OF ROAD PAVEMENT EMBANKMENT ON THE APPROACHES TO ROAD BRIDGES." In Integration of traditional and innovation processes of development of modern science. Publishing House “Baltija Publishing”, 2020. http://dx.doi.org/10.30525/978-9934-26-021-6-41.
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The laws of unsaturated and capillary movement of water in soils are analyzed, which are complex and insufficiently studied, but significantly affect the condition of the ground. Experience in the design and construction of the subsoil has shown that during the excavation works can significantly change the conditions of soils and their water-thermal regime. Therefore, the characteristics of soils used in stability calculations should be determined taking into account the subsequent condition of the soil in the conditions of occurrence, as well as the possible change of these conditions during construction and maintenance. One of the urgent tasks is to improve the methods of regulating the water-thermal regime of roads. By changing the conditions of its course or the type of water-thermal regime itself, significant successes can be achieved in improving the maintenance of roads, engineering and transport facilities. Dangerous effect of these factors on the embankment of the ground is manifested in the formation of wetting, wetting of the soil and layers of pavement, resulting in reduced density, strength of soils, subsidence, swelling and loss of continuity due to cracking. As a result, the strength of the road structure, the flatness of the carriageway, the durability of the pavement and the adhesion of the wheels to the roadway are reduced. The most dangerous for roads are moisture accumulation, freezing, thawing of the ground, intensive heating and intensive cooling of the layers of pavement. The analysis of regularities of formation of a water-thermal regime of a ground and its regulation at the expense of the device of optimum capillary-interrupting layers is carried out. The laws of soil moisture when raising capillary water showed that when the layer of the embankment with a high coefficient of impregnation is dehydrated over the layer with a lower coefficient, the speed of moving capillary water into the upper soil layers drops sharply. This fall occurs as a result of changes in the relationship between the driving forces of the menisci and the forces of resistance of capillary water in the soil. The process of unsaturated movement of water in the soil is determined by the combination of many factors that characterize the capillary system of the soil. The calculation uses complex indicators of soil water movement conditions, which are established experimentally for each variety and soil density at optimal humidity, as well as water filtration coefficients in the soil. To establish the relationship between these experimental data and the required values that determine the capillary system of the soil, the filtration of water in the soil was considered. Determining the optimal capillary system of the soil and establishing the unstable distribution of own capillary water in the structures of high embankments will ensure the strength of approaches to road bridges. The method of calculating the determination of the optimal composition of the road layers taking into account the processes of water-thermal regime and capillary movement of water has been improved. The algorithm of calculation in the program Microsoft Excel for selection of optimum structure of a ground cloth of a high embankment on approaches to automobile bridges is offered.
Conference papers on the topic "Cracking intensity"
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Kostrivas, Tasos, Lee Smith, and Mike Gittos. "Sustained Load Cracking of Titanium Alloy Weldments." In ASME 2005 24th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2005. http://dx.doi.org/10.1115/omae2005-67474.
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Failure of critical titanium parts, including some offshore components, has drawn attention to delayed cracking in Ti-6Al-4V alloys, but, given good design and alloy variant selection, such failures are avoidable. Delayed cracking, or sustained load cracking (SLC), can occur at low to moderate temperature (approximately: −50 to 200°C), depending on the titanium alloy and condition. Appropriate testing methods are required to generate stress intensity threshold values (KISLC) that can be incorporated into the design of titanium structures and recommendations are needed on the optimum chemistry and microstructure for greatest resistance. In the present work threshold stress intensity factor data (KISLC) were generated for Ti-6Al-4V alloy sheet, forgings, pipe and weldments using two different rising stress intensity factor test methods. It is concluded that material with a beta-annealed microstructure and low oxygen content (i.e. extra-low interstitial material such as ASTM Grades 23 and 29), has high resistance to SLC and that weld metal and transformed heat-affected zone also perform well, before and after postweld heat treatment, provided interstitial element pick-up during welding is prevented. Purchasing material in a general ‘mill annealed’ condition is not recommended without specifying acceptable microstructures. Further refinement of test method is also recommended for defining KISLC.
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Homrossukon, Samerjit, Sheldon Mostovoy, and Judith A. Todd. "Investigation of Hydrogen Assisted Cracking in Pressure Vessels." In ASME 2006 Pressure Vessels and Piping/ICPVT-11 Conference. ASMEDC, 2006. http://dx.doi.org/10.1115/pvp2006-icpvt-11-93923.
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Hydrogen assisted cracking (HAC) has been investigated in high strength 4140 and low strength Z17D pressure vessel steels, charged at −50 mA/cm2 in 1N H2SO4 + 25 mg/1 As2O3 and tested under three-point bend decreasing load. The HAC growth rate for Z17D steel (1.4×10−7 cm/s) was found to be approximately two orders of magnitude slower than that of 4140 steel (3.3×10−5 cm/s), while the threshold stress intensity factor for Z17D steel (∼37 MPa√m) was significantly higher than that of 4140 steel (∼7 MPa√m). This research will show that a single analytical model, based on the hypothesis that hydrogen both reduces crack resistance (R) and increases crack driving force (G), can explain HAC in 4140 and Z17D steels. The model predicts the hydrogen concentration required to initiate HAC as a function of the stress intensity factor and yield strength of the steel. Hydrogen-induced reduction of R was found to dominate HAC in 4140 steel, while hydrogen-induced reduction of R was combined with an increase in G for HAC cracking of Z17D steel.
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Sano, Hayato, Koji Takahashi, and Kotoji Ando. "Prevention of Stress Corrosion Cracking of SUS304 by Tensile Overload." In ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/pvp2010-25573.
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The effects of overload on the threshold stress intensity factor (KISCC) for stress corrosion cracks (SCC) in stainless steel were studied. Tensile overload was applied to a wedge opening loaded specimen of SUS304, and SCC tests were carried out to determine the resultant KISCC. The value of KISCC was found to increase with increasing stress intensity caused by tensile overload. Comparison of the effects of tensile overload on KISCC of SUS304 and SUS316 revealed that the effect on KISCC of SUS304 was smaller than that of SUS316.
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Rudland, D., D. J. Shim, and A. Csontos. "Natural Flaw Shape Development Due to Stress Corrosion Cracking." In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61205.
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Typical ASME Section XI subcritical cracking analyses assume an idealized flaw shape driven by stress intensity factors developed for semi-elliptical shaped flaws. Recent advanced finite element analyses (AFEA) conducted by both the US NRC and the nuclear industry for long circumferential indications found in the pressurizer nozzle dissimilar metal welds at the Wolf Creek power plant, suggest that the semi-elliptical flaw assumption may be overly conservative in some cases. The AFEA methodology that was developed allowed the progression of a planar flaw subjected to typical SCC-type growth laws by calculating stress intensity factors at every nodal point along the crack front, and incrementally advancing the crack front in a more natural manner. Typically crack growth analyses increment the semi-elliptical flaw by considering only the stress intensity factor at the deepest and surface locations along the crack front, while keeping the flaw shape semi-elliptical. In this paper, a brief background to the AFEA methodology and the analyses conducted in the Wolf Creek effort will be discussed. In addition, the natural behavior of surface cracks under normal operating conditions (plus welding residual stress) will be investigated and compared to the semi-elliptical assumption. Conclusions on the observation of when semi-elliptical flaw assumptions are appropriate will be made. These observations will add insight into the conservatism of using an idealized flaw shape assumption.
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Shim, Do-Jun, Fredrick Brust, and Gery Wilkowski. "Accounting for Natural Crack Growth Shapes During Environmental Cracking." In 2012 9th International Pipeline Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/ipc2012-90570.
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Environmental cracking, such as stress-corrosion cracking (SCC), is a significant issue for a variety of industries, such as those dealing with power generation — nuclear, oil and gas production, and pipeline transmission, etc. SCC is particularly of concern in that catastrophic failures can occur even at low applied stress levels (e.g., residual stress produced by welding). Thus, it is critical to evaluate the behavior of SCC for structural integrity assessments. In this paper, three different crack growth methods (i.e., idealized crack growth analysis, crack growth analysis using finite element alternating method; FEAM, and the natural crack growth method) are summarized. These methods all utilize the stress intensity factor for crack growth evaluations. Thus, these methods can be used for assessment of environmental cracking that is based on stress intensity factor. Various examples are shown in this paper to demonstrate the applicability of these methods. Comparisons of results obtained from different methods are also provided in this paper.
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Richards, Mark D., Timothy S. Weeks, J. David McColskey, Bo Wang, and Yong-Yi Wang. "Fatigue Pre-Cracking Curved Wide Plates in Bending." In 2010 8th International Pipeline Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/ipc2010-31468.
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Curved wide plate (CWP) testing in tension, on API 5L X100 pipes of 36-inch (916-mm) diameter and 0.75-inch (19-mm) wall thickness, has been initiated in support of strain-based design using high strength steel for oil and gas pipeline applications. The CWP tests are being used to optimize and validate welding procedures and to determine the defect tolerance within the girth welds. A traditional pre-requisite for fracture mechanics testing is a final extension of a crack via fatigue pre-cracking to produce a representative flaw. A method of fatigue pre-cracking CWP specimens for final notch preparation in bending was developed to meet ASTM guidelines for fracture mechanics testing. Fatigue pre-cracking for the present specimen geometry was possible in bending due to lower requisite force capacity equipment which allowed for greater cyclic loading frequencies. In order to achieve sufficient stress levels for fatigue crack growth in the curved plate, a stress field analysis was performed to optimize the loading support configuration in four-point bending. In addition to the stress field analysis, a 3-D finite element model of the CWP specimen was generated to analyze the notched CWP specimen in four-point bending. Finite element analysis (FEA) results and experimental data were used to confirm the hypothesis that, under the proposed loading arrangement, the closed-form solutions for stress-intensity (K) of flat plates in bending can be used to approximate the K for CWP specimens in bending. Validation of a solution for stress-intensity factor subsequently allowed the determination of force amplitude levels for fatigue crack growth. Force and crack mouth opening displacement (CMOD) data were analyzed to correlate compliance with crack length measurements. From experimental results, a method was developed that enable the repeatable and well characterized extension of surface flaws by fatigue pre-cracking in curved wide plate specimens in bending.
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Lam, Poh-Sang, Changmin Cheng, Yuh J. Chao, Robert L. Sindelar, Tina M. Stefek, and James B. Elder. "Stress Corrosion Cracking of Carbon Steel Weldments." In ASME 2005 Pressure Vessels and Piping Conference. ASMEDC, 2005. http://dx.doi.org/10.1115/pvp2005-71327.
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An experiment was conducted to investigate the role of weld residual stress on stress corrosion cracking in welded carbon steel plates prototypic to those used for nuclear waste storage tanks. Carbon steel specimen plates were butt-joined with Gas Metal Arc Welding technique. Initial cracks (seed cracks) were machined across the weld and in the heat affected zone. These specimen plates were then submerged in a simulated high level radioactive waste chemistry environment. Stress corrosion cracking occurred in the as-welded plate but not in the stress-relieved duplicate. A detailed finite element analysis to simulate exactly the welding process was carried out, and the resulting temperature history was used to calculate the residual stress distribution in the plate for characterizing the observed stress corrosion cracking. It was shown that the cracking can be predicted for the through-thickness cracks perpendicular to the weld by comparing the experimental KISCC to the calculated stress intensity factors due to the welding residual stress. The predicted crack lengths agree reasonably well with the test data. The final crack lengths appear to be dependent on the details of welding and the sequence of machining the seed cracks, consistent with the prediction.
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Takahashi, Koji, Yuji Miyazaki, Yasuaki Hashikura, and Kotoji Ando. "Improvement of the Threshold Stress Intensity Factor for Stress Corrosion Cracking in SUS316 by Tensile Overload." In ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/pvp2010-25610.
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The effects of overload on the threshold stress intensity factor (KISCC) for stress corrosion cracks (SCC) in stainless steel were studied. Tensile overload was applied to a wedge opening loaded specimen of SUS316, and SCC tests were carried out to determine the resultant KISCC. As a result, the value of KISCC was found to increase with increasing stress intensity factor by tensile overload. The effects of tensile overload on KISCC and the threshold stress intensity factor range for fatigue (ΔKth) were compared. It was found that the effect of tensile overload on KISCC was larger than that of ΔKth.
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Zhang, Yi-liang, Rui-bin Gou, Ji-min Li, Gong-tian Shen, and Jing Wang. "Experimental Study on Critical Derivative of Cracking Magnetic Field Intensity in High Frequency Fatigue Test." In ASME 2010 Pressure Vessels and Piping Division/K-PVP Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/pvp2010-25531.
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This paper focuses on engineering application of metal magnetic memory (MMM) method. High-cycle fatigue test were applied to a large number of defect-free samples, and MMM signals were captured before fatigue fracturing. A concept of critical magnetic intensity (Hp) derivative (dHp/dx) of cracking was proposed. To study the characteristics of Hp and its derivative (dHp/dx) during cracking, fatigue test were applied to a total number of 50 pieces of Q235, 16MnR and base metal and welded specimens. In different fatigue periods, MMM signals were tested and microscopic metallographic were observed, so as to quantitatively analyze Hp and dHp/dx from both macro and micro angles. The results show that various materials differ in their critical dHp/dx limit, which could be the fatigue crack initiation time. It thus proves that MMM has special efficiency in the diagnosis of premature defects and stress concentration of metal structures.
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Nibur, K. A., B. P. Somerday, C. San Marchi, and D. K. Balch. "Measurement of Sustained-Load Cracking Thresholds for Steels in Hydrogen Delivery and Storage." In ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61298.
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Threshold stress intensity factors at crack arrest have been measured for three commercial low alloy pressure vessel steels, SA372 grade J, DOT 3AAX and DOT 3T as well as X100 line pipe steel using sustained load testing. Testing conditions were consistent with the recently published Article KD-10 from Section VIII, Division 3 of the ASME Boiler and Pressure Vessel Code. Measured threshold values for these steels suggest a higher resistance to hydrogen-assisted fracture than previously expected, however some improvements to the methodology of Article KD-10 may be required to ensure conservative results are measured. Specifically, conservative measurements of threshold stress intensity factor for hydrogen-assisted fracture cannot be determined without crack propagation.
Reports on the topic "Cracking intensity"
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FATIGUE PERFORMANCE OF RIB-TO-DECK JOINTS STRENGTHENED WITH INTERNAL WELDING. The Hong Kong Institute of Steel Construction, August 2022. http://dx.doi.org/10.18057/icass2020.p.268.
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"Rib-to-deck joints of orthotropic steel decks (OSDs) in steel bridges are susceptible to longitudinal fatigue cracking, which often results in considerable costs as well as traffic interruption. This paper numerically simulated the Crack II of rib-to-deck joint and analyzed the crack failure mode of the joint. To mitigate such cracking, a strengthening method using internal welding was investigated. The effects of initial crack size, internal weld size and crack depth on the stress intensity factor (SIF) of crack tip on rib-to-deck fatigue details were studied by finite element method. The finite element analysis demonstrated that the proposed method can significantly improve the detailed stress range of the weld root, lead to the transfer of crack development mode, and prolong the fatigue life of rib-to-deck joints. Numerical analysis validated the beneficial effect of strengthening measures on the stress intensity factors at crack tips. Calculation of stress intensity factors at crack tips resulted that the crack development law, and the application range of reinforcement method was analyzed. This study provided a reference to the design and application of internal welding in the strengthening of weld details in OSDs."