Статті в журналах: "Rupture criterion"

1

Li Shiyu. "Earthquake rupture model and rupture criterion." Physics and Chemistry of the Earth 17 (January 1990): 55–61. http://dx.doi.org/10.1016/0079-1946(89)90009-8.

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2

Walczak, Jan. "On an energy creep-rupture criterion." International Journal of Mechanical Sciences 28, no. 2 (January 1986): 71–81. http://dx.doi.org/10.1016/0020-7403(86)90015-9.

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3

Varble, Nicole, Gabriel Trylesinski, Jianping Xiang, Kenneth Snyder, and Hui Meng. "Identification of vortex structures in a cohort of 204 intracranial aneurysms." Journal of The Royal Society Interface 14, no. 130 (May 2017): 20170021. http://dx.doi.org/10.1098/rsif.2017.0021.

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An intracranial aneurysm (IA) is a cerebrovascular pathology that can lead to death or disability if ruptured. Abnormal wall shear stress (WSS) has been associated with IA growth and rupture, but little is known about the underlying flow physics related to rupture-prone IAs. Previous studies, based on analysis of a few aneurysms or partial views of three-dimensional vortex structures, suggest that rupture is associated with complex vortical flow inside IAs. To further elucidate the relevance of vortical flow in aneurysm pathophysiology, we studied 204 patient IAs (56 ruptured and 148 unruptured). Using objective quantities to identify three-dimensional vortex structures, we investigated the characteristics associated with aneurysm rupture and if these features correlate with previously proposed WSS and morphological characteristics indicative of IA rupture. Based on the Q -criterion definition of a vortex, we quantified the degree of the aneurysmal region occupied by vortex structures using the volume vortex fraction ( vVF ) and the surface vortex fraction ( sVF ). Computational fluid dynamics simulations showed that the sVF , but not the vVF , discriminated ruptured from unruptured aneurysms. Furthermore, we found that the near-wall vortex structures co-localized with regions of inflow jet breakdown, and significantly correlated to previously proposed haemodynamic and morphologic characteristics of ruptured IAs.

4

Aubertin, Michel, and Richard Simon. "Un critère de rupture multiaxial pour matériaux fragiles." Canadian Journal of Civil Engineering 25, no. 2 (April 1, 1998): 277–90. http://dx.doi.org/10.1139/l97-092.

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Most brittle materials show little straining at failure and an ultimate strength that depends upon loading geometry. The surface that defines failure in stress space has a characteristic shape that may be defined by an appropriate mathematical criterion. In this paper, the authors present a simple multiaxial criterion formulated from two quadric functions. Under conventional triaxial compression, the MSDP criterion reduces to the Mises-Schleicher criterion at low mean stress and it takes the shape of the conical Nadai-Drucker-Prager criterion at higher mean stress. The MSDP criterion can be expressed from the three principal stresses or from the usual invariantsI1, J2, and J3. It includes four characteristic parameters, each having a particular significance regarding material properties. The validity of the criterion is shown using experimental results taken from the literature on rock, concrete, and grey cast iron.Key words: failure, brittle materials, rock, concrete, cast iron.

5

Huddleston, R. L. "An Improved Multiaxial Creep-Rupture Strength Criterion." Journal of Pressure Vessel Technology 107, no. 4 (November 1, 1985): 421–29. http://dx.doi.org/10.1115/1.3264476.

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An improved strength model is developed for predicting creep rupture under multiaxial stress states. The new model incorporates three independent stress parameters and distinguishes between life under tensile versus compressive stress states. Assessments of the new model based on experimental biaxial creep-rupture data for type 304 stainless steel tested at 593°C show the new model to be significantly more accurate than the classical criteria of von Mises, Tresca, or Rankine.

6

Dai, Zongfu, and Shouci Lu. "Liquid bridge rupture distance criterion between spheres." International Journal of Mineral Processing 53, no. 3 (April 1998): 171–81. http://dx.doi.org/10.1016/s0301-7516(97)00078-1.

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7

Li, Chun Guang, Xiu Run Ge, Hong Zheng, and Shui Lin Wang. "Two-Parameter Parabolic Mohr Strength Criterion and Its Damage Regularity." Key Engineering Materials 306-308 (March 2006): 327–32. http://dx.doi.org/10.4028/www.scientific.net/kem.306-308.327.

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A series of formulas about two-parameter parabolic Mohr strength criterion(2-PP Mohr criterion) are derived. Based on the results of uniaxial tension and uniaxial compression tests, the parameters involved in the criterion can be easily determined, then the criterion in terms of the major principal stress and the minor principal stress is derived, and the damage pattern is also discussed. At last, the formulas about the rupture angle and the friction angle are presented, and their relationship is also given. 2-PP Mohr criterion can describe not only shear but also tensile failure. In this criterion the ratio of the uniaxial compression strength and the uniaxial tension strength is not confined as in Griffith criterion. The formula about the rupture angle provides steady theoretical foundation for determining the direction of crack faces and damage patterns in the computation of macro crack propagation. In fact, Griffith criterion is only a special case of the two-parameter parabolic Mohr strength criterion proposed in this present paper.

8

Paraskevas, Kosmas I., Alexandros A. Tzovaras, Vassilios Stathopoulos, Fotini Gentimi, and Dimitri P. Mikhailidis. "Increased Fluorodeoxyglucose Uptake Following Endovascular Abdominal Aortic Aneurysm Repair: A Predictor of Endoleak?" Open Cardiovascular Medicine Journal 4, no. 1 (April 8, 2010): 117–19. http://dx.doi.org/10.2174/1874192401004010117.

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The main criterion for abdominal aortic aneurysm (AAA) repair is an AAA diameter ≥5.5 cm. However, some AAAs rupture when they are smaller. Size alone may therefore not be a sufficient criterion to determine rupture risk. Fluorodeoxyglucose (FDG) uptake is increased in the presence of inflammation and it was suggested that this may be a better predictor of rupture risk than AAA size. Furthermore, increased FDG uptake following endovascular AAA repair may be an indirect predictor of continuous AAA sac enlargement due to the presence of an endoleak (even if this is not detected by imaging modalities) and/or increased AAA rupture risk. The role of FDG uptake needs to be explored further in the management of AAAs.

9

Jusko, Maciej, Piotr Kasprzak, Alicja Majos, and Waclaw Kuczmik. "The Ratio of the Size of the Abdominal Aortic Aneurysm to That of the Unchanged Aorta as a Risk Factor for Its Rupture." Biomedicines 10, no. 8 (August 17, 2022): 1997. http://dx.doi.org/10.3390/biomedicines10081997.

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Background: A ruptured abdominal aortic aneurysm is a severe condition associated with high mortality. Currently, the most important criterion used to estimate the risk of its rupture is the size of the aneurysm, but due to patients’ anatomical variability, many aneurysms have a high risk of rupture with a small aneurysm size. We asked ourselves whether individual differences in anatomy could be taken into account when assessing the risk of rupture. Methods: Based on the CT scan image, aneurysm and normal aorta diameters were collected from 186 individuals and compared in patients with ruptured and unruptured aneurysms. To take into account anatomical differences between patients, diameter ratios were calculated by dividing the aneurysm diameter by the diameter of the normal aorta at various heights, and then further comparisons were made. Results: It was found that the calculated ratios differ between patients with ruptured and unruptured aneurysms. This observation is also present in patients with small aneurysms, with its maximal size below the level that indicates the need for surgical treatment. For small aneurysms, the ratios help us to estimate the risk of rupture better than the maximum sac size (AUC: 0.783 vs. 0.650). Conclusions: The calculated ratios appear to be a valuable feature to indicate which of the small aneurysms have a high risk of rupture. The obtained results suggest the need for further confirmation of their usefulness in subsequent groups of patients.

10

Gao, C. Y., and Y. T. Fang. "Strain-Based Damage Tolerance of Cylindrical Shells Subjected to Transient Loading and Its Application." Key Engineering Materials 293-294 (September 2005): 501–8. http://dx.doi.org/10.4028/www.scientific.net/kem.293-294.501.

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In this paper, a new approach to damage tolerance determination, which is related to the critical rupture strain, is proposed for cylindrical shells subjected to inner transient high-pressure loading. The relation of damage variable and circumferential plastic strain is deduced on the basis of a damage evolution equation as well as a simplified dynamic viscoplastic constitutive equation. The value of damage variable can be obtained then if the strain is known by strain measurement, and the damage tolerance just corresponds to the rupture strain of the structure. Further, the damage tolerance has been applied as the strain-based rupture criterion in the FE simulation of the dynamic fracture process for transient-pressurized cylindrical shells. Especially for the notched shells, the strain concentration effect of notches on the rupture criterion is analyzed quantitatively.

11

Di Iorio, S., L. Briottet, Edgar F. Rauch, and Didier Guichard. "Damage Mechanisms and Rupture Criterion of PM Ti-6Al-4V at 20K." Materials Science Forum 482 (April 2005): 287–90. http://dx.doi.org/10.4028/www.scientific.net/msf.482.287.

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A two parameters rupture criterion for Ti-6Al-4V is proposed, based on cryogenic rupture tests. microstructural observations and FEM analysis,. The damage mechanisms including the cavities nucleation process are analyzed. Moreover, the final steps of rupture are discussed with the help of the thermo-mechanical coupling mechanisms that are expected to operate at low temperatures.

12

YOSHIDA, Shingo. "Two-dimensional rupture propagation controlled by Irwin's criterion." Journal of Physics of the Earth 33, no. 1 (1985): 1–20. http://dx.doi.org/10.4294/jpe1952.33.1.

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13

Niklas, Natalia, Piotr Gutowski, Arkadiusz Kazimierczak, and Paweł Rynio. "Abdominal Aortic Aneurysm Morphology as an Essential Criterion for Stratifying the Risk of Aneurysm Rupture." Journal of Clinical Medicine 11, no. 4 (February 11, 2022): 933. http://dx.doi.org/10.3390/jcm11040933.

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The current stratification model of aneurysm rupture seems to be insufficient in some clinical cases. In our study, we determined the differences in wall structure between ruptured and unruptured aneurysms. We obtained computed tomography angiograms and categorized them into the following three groups, consisting of 49 patients each: the group with ruptured abdominal aortic aneurysms (rAAA), symptomatic (sAAA), and asymptomatic (aAAA). The three-dimensional AAA anatomy was digitally reconstructed for each patient through semi-automatically obtained segmentation, and each aneurysm was distinguished by the following three parameters: AFL (aneurysm flow lumen), ILT (intraluminal thrombus), and calcifications. The AFL volume was greater in rAAA compared with aAAA (p = 0.004), the ILT volume was greater in aAAA than in rAAA (p = 0.013), and the AFL/ILT surface ratio was bigger in rAAA than in aAAA (p < 0.001), sAAA than in aAAA (p = 0.033), and rAAA than in sAAA (p = 0.016). AFL/ILT surface*100 was defined as an independent predictive factor of rAAA to aAAA (OR 1.187; 95% CI 1.099–1.281), to sAAA (OR 1.045; 95% CI 1.004–1.087), and in sAAA vs. aAAA (OR 1.067; 95% CI 1.017–1.119). Consequently, the wall of rAAA differs significantly from unruptured aneurysms. The AFL/ILT surface ratio might indicate an increased risk of aneurysm rupture and the occurrence of symptoms in AAA.

14

Hanna, Anis, Arti V. Shinde, and Nikolaos G. Frangogiannis. "Validation of diagnostic criteria and histopathological characterization of cardiac rupture in the mouse model of nonreperfused myocardial infarction." American Journal of Physiology-Heart and Circulatory Physiology 319, no. 5 (November 1, 2020): H948—H964. http://dx.doi.org/10.1152/ajpheart.00318.2020.

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We show that cardiac rupture accounts for 50% of deaths in C57BL/6J mice undergoing nonreperfused myocardial infarction protocols. Overestimation of rupture events in published studies likely reflects the low specificity of hemothorax as a criterion for documentation of rupture. In contrast, identification of a gross rupture site has high specificity and low sensitivity. We also show that mice dying of rupture have increased macrophage influx and attenuated myofibroblast infiltration in the infarct. These findings are consistent with a role for perturbations in the balance between inflammatory and reparative responses in the pathogenesis of postinfarction cardiac rupture. We also report that the male predilection for rupture in infarcted mice is not associated with increased inflammatory activation of myeloid cells.

15

Lee, Han Ul, and Dong Woo Cho. "Calculation of Reference Cutting Force as a Criterion of Rough Milling Using FEM Analysis." Materials Science Forum 526 (October 2006): 43–48. http://dx.doi.org/10.4028/www.scientific.net/msf.526.43.

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For effective rough milling, an optimized criterion is required to select the feedrate. In this study, a method to obtain the most appropriate reference cutting force for rough milling was developed. The reference cutting force was determined by considering the transverse rupture strength of the tool material and the area of the rupture surface. A finite element method analysis was performed to accurately calculate the area of the rupture surface. Using the analyzed results, the effect of various cutting parameters on the chipping phenomenon was determined. The calculation method for the reference cutting force considered the area of the rupture surface, the effect of the rake angle, and the axial depth of cut. The experimental results clearly show that the reference cutting force obtained from the proposed method met the desired constraints.

16

Michel, B., J. Sercombe, and G. Thouvenin. "A new phenomenological criterion for pellet–cladding interaction rupture." Nuclear Engineering and Design 238, no. 7 (July 2008): 1612–28. http://dx.doi.org/10.1016/j.nucengdes.2008.01.012.

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17

KIM, HEON YOUNG, JONG GIL CHOI, MIN GUN KIM, KANG WOOK LEE, DAE YUL HA, and TAE JUNG YEO. "CUMULATIVE IMPACT DAMAGE EVALUATION OF AUTOMOTIVE ALUMINUM BUMPER BEAM." International Journal of Modern Physics B 22, no. 09n11 (April 30, 2008): 1584–91. http://dx.doi.org/10.1142/s0217979208047110.

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We performed numerical analyses using an explicit code to evaluate the cumulative impact damage of an automotive aluminum front-end bumper back beam during low-speed crash events, as described by CMVSS215. we used a coupled numerical analysis scheme and considered the several fracture criterion such as EWK rupture model and plastic strain limit in the PAM-CRASH code to improve our damage and fracture estimates. Tensile test experiments for the notched and un-notched specimens were conducted to tune the performance of the EWK rupture model; The resulting material properties and fracture criterion were incorporated into the numerical analyses of the low-speed crash events. The simulation results were compared with the impact test.

18

Sato, Tamao, and Hiroo Kanamori. "Beginning of earthquakes modeled with the Griffith's fracture criterion." Bulletin of the Seismological Society of America 89, no. 1 (February 1, 1999): 80–93. http://dx.doi.org/10.1785/bssa0890010080.

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Abstract We present a source model for the beginning of earthquakes based on the Griffith's fracture criterion. The initial state is a critical state of pre-existing circular fault, which is on the verge of instability. After the onset of instability, the fault grows with a progressively increasing rupture speed, satisfying the condition of fracture energy balance at the crack tip. We investigate the difference in rupture growth patterns in two classes of models that are considered to represent end-member cases. In the first model (Spontaneous model), we assume that the surface energy varies smoothly as a function of position in the crust. In this model, faults with small initial dimensions grow in regions with small surface energy, and those with large initial dimensions, in large surface energy. The rupture velocity increases progressively until it reaches its limiting value. The synthetic velocity seismogram at far field shows a weak initial phase during the transitional stage to limiting velocity. The time taken to reach the limiting velocity is proportional to the initial length of pre-existing fault. Therefore, the duration of the weak initial phase scales with the initial length of fault. In the second model (Trigger model), we envisage that there are many pre-existing faults in the crust with various lengths. These faults are stable because they encounter some obstacle at their ends (e.g., fault segmentation, strong asperity, etc.). This situation is modeled with a local increase of surface energy near the ends of fault. An earthquake is triggered when the obstacle is suddenly removed (i.e., sudden weakening) or the stress is suddenly increased locally to overcome the obstacle. Once an earthquake is triggered, the fault growth is governed by the ambient surface energy. In this model, the rupture speed attains its limiting velocity almost instantly. The synthetic velocity seismogram at far field shows an abrupt, linear increase in amplitude without the weak initial phase that appears in the Spontaneous model. Both models can be unified using a trigger factor defined as a fractional perturbation of the surface energy at the ends of fault relative to the ambient surface energy. The Spontaneous model is characterized by a small trigger factor, and the Trigger model, by a large trigger factor. Thus, the seismic initiation phase with and without the slow initial phase can both occur depending on the trigger factor. The variability in the observed seismic initiation phase may represent a variation surface energy (strength) distribution surrounding the pre-existing cracks. A theoretical consideration of rupture arrest by barriers using the Griffith's fracture criterion does not support the scaling relation between the nucleation moment and the eventual size of earthquake.

19

Maruyama, Kouichi, and Kyosuke Yoshimi. "Influence of Data Analysis Method and Allowable Stress Criterion on Allowable Stress of Gr.122 Heat Resistant Steel." Journal of Pressure Vessel Technology 129, no. 3 (June 20, 2006): 449–53. http://dx.doi.org/10.1115/1.2748825.

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Long-term creep rupture life is usually evaluated from short-term data by a time-temperature parameter (TTP) method. The allowable stress of Gr.122 steel listed in the ASME code has been evaluated by this method and is recognized to be overestimated. The objective of the present study is to understand the causes of the overestimation and propose appropriate methodology for avoiding the overestimation. The apparent activation energy Q for rupture life of the steel changes from a high value of short-term creep to a low value of long-term creep. However, the decrease in Q is ignored in the conventional TTP analyses, resulting in the overestimation of rupture life. A multiregion analysis of creep rupture data is employed to avoid the overestimation; in the analysis creep rupture data are divided into a couple of regions so that the Q value is unique in each divided region. The multiregion analysis provides a good fit to the data and the lowest value of 105h creep rupture strength among the three ways of data analysis examined. A half of 0.2% proof stress cannot provide an appropriate boundary for dividing data to be used in the multiregion analysis. In the 2001 edition of the ASME code an F average concept has been proposed as a substitution for the safety factor of 2∕3 for average rupture stress. The allowable stress of Gr.122 steel changes significantly depending on the allowable stress criteria as well as the methods of rupture data analysis: i.e., from 74MPato48MPa.

20

Kobayashi, A. S., A. F. Emery, W. J. Love, and Y. H. Chao. "Subsize Experiments and Numerical Modeling of Axial Rupture of Gas Transmission Lines." Journal of Pressure Vessel Technology 110, no. 2 (May 1, 1988): 155–60. http://dx.doi.org/10.1115/1.3265580.

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The experimental facilities and the numerical modeling for studying dynamic axial rupture of pressurized subsize pipes are reviewed. Selected results from 46 pipe rupture tests and related numerical analyses are used to show that the axial flap stretching is the dominant energy sink, the crack tip opening angle (CTOA) is a viable ductile crack extension criterion, and there exists a crack tip strain field which promotes crack curving at arrest.

21

Suzuki, Tomoaki, Hitoshi Hasegawa, Kohei Shibuya, Hidemoto Fujiwara, and Makoto Oishi. "Clinical and Hemodynamic Features of Aneurysm Rupture in Coil Embolization of Intracranial Aneurysms." Diagnostics 14, no. 11 (June 6, 2024): 1203. http://dx.doi.org/10.3390/diagnostics14111203.

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Intraprocedural rupture (IPR) during coil embolization (CE) of an intracranial aneurysm is a significant clinical concern that necessitates a comprehensive understanding of its clinical and hemodynamic predictors. Between January 2012 and December 2023, 435 saccular cerebral aneurysms were treated with CE at our institution. The inclusion criterion was extravasation or coil protrusion during CE. Postoperative data were used to confirm rupture points, and computational fluid dynamics (CFD) analysis was performed to assess hemodynamic characteristics, focusing on maximum pressure (Pmax) and wall shear stress (WSS). IPR occurred in six aneurysms (1.3%; three ruptured and three unruptured), with a dome size of 4.7 ± 1.8 mm and a D/N ratio of 1.5 ± 0.5. There were four aneurysms in the internal carotid artery (ICA), one in the anterior cerebral artery, and one in the middle cerebral artery. ICA aneurysms were treated using adjunctive techniques (three balloon-assisted, one stent-assisted). Two aneurysms (M1M2 and A1) were treated simply, yet had relatively small and misaligned domes. CFD analysis identified the rupture point as a flow impingement zone with Pmax in five aneurysms (83.3%). Time-averaged WSS was locally reduced around this area (1.3 ± 0.7 [Pa]), significantly lower than the aneurysmal dome (p < 0.01). Hemodynamically unstable areas have fragile, thin walls with rupture risk. A microcatheter was inserted along the inflow zone, directed towards the caution area. These findings underscore the importance of identifying hemodynamically unstable areas during CE. Adjunctive techniques should be applied with caution, especially in small aneurysms with axial misalignment, to minimize the rupture risk.

22

Contesti, E., G. Cailletaud, and C. Levaillant. "Creep Damage in 17–12 SPH Stainless Steel Notched Specimens: Metallographical Study and Numerical Modeling." Journal of Pressure Vessel Technology 109, no. 2 (May 1, 1987): 228–35. http://dx.doi.org/10.1115/1.3264901.

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Creep-rupture tests on notched specimens of 17–12 SPH stainless steel are performed at elevated temperature (600°C). Metallographic examination allows the quantitative estimation of the intergranular cracking damage occurring during creep tests. Numerical computations based on currently used rupture criteria are performed and compared to both intergranular damage profile and creep life. With regards to the intergranular damage profile measured by interrupting tests on the 1-mm notch radius specimen, Von Mises stress criterion does not predict the experimental location of the maximum damage, because of the influence of stress-triaxiality on the rupture process.

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Mamadou, Diallo, Mohammed El Emin Taleb Maouloud, Kébé Fatoumata Binta, Cissé Mohamed Yaya, Sow Rouguiatou, Diallo Elhadj Djiba DH, Omar Marghich, Abdeslam Bouassria, Ouadii Mouaqit, and El Bachir Benjello. "Right Diaphragmatic Rupture with Total Passage of the Liver into the Thorax: A Case Report." SAS Journal of Surgery 10, no. 04 (April 18, 2024): 467–71. http://dx.doi.org/10.36347/sasjs.2024.v10i04.015.

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Traumatic rupture of the right diaphragmatic dome with herniation of the liver into the thorax is a rare lesion. It is often part of a polytrauma, for which it is a criterion of severity. Whether early or late, it exposes the patient to cardiopulmonary complications due to compression. Right diaphragmatic rupture is difficult to diagnose. Its clinical signs are not very specific, and imaging can be misleading, as it visualizes the ascending organs but not the rupture itself. The thoracic approach is often preferred because of the difficulty of exposing the diaphragm in the presence of the liver. We report a case of right diaphragmatic rupture with total passage of the liver into the thorax following an MVA in a polytrauma patient.

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Mahmoud, A., A. Outouzale, A. Mansour, B. Chahid, B. Sissoukhou, A. Hamri, Y. Narjis, and R. Benelkhaiat. "Right Diaphragmatic Rupture Post Earthquake." SAS Journal of Surgery 10, no. 01 (January 4, 2024): 1–4. http://dx.doi.org/10.36347/sasjs.2024.v10i01.001.

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Traumatic rupture of the right diaphragmatic dome with herniation of the liver into the thorax is a rare lesion. It is often integrated into the context of multiple trauma, of which it is a criterion of severity. It exposes you, early or late, to cardiopulmonary complications due to compression. The diagnosis of a right diaphragmatic rupture is difficult to establish. Indeed, its clinical signs are not very specific and the imaging can be faulty because it visualizes the ascended organs but more difficultly the rupture itself. The thoracic approach is often preferred due to the difficulties of exposing the diaphragm in the presence of the liver. We report a case of a right diaphragmatic rupture with isolated and total intra-thoracic passage of the liver diagnosed on the fifth day of hospitalization in a multiple trauma patient.

25

Wang, Rui, Jian-biao Bai, Shuai Yan, Yuan-ba Song, and Guang-dong Wang. "An Improved Numerical Simulation Approach for the Failure of Rock Bolts Subjected to Tensile Load in Deep Roadway." Geofluids 2020 (October 10, 2020): 1–21. http://dx.doi.org/10.1155/2020/8888390.

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Our goal was to develop an effective research tool for roadways with significant deformations supported by rock bolts. The improved numerical simulation approach is constructed through additional development of FLAC3D. The aim is to modify the shortcoming that the original model in FLAC3D regards the plastic tensile strain of any arbitrary rock bolt element node as the rupture discrimination criterion. The FISH programming language is adopted to conduct the secondary development and to embed the revised model into the main program of FLAC3D. Taking an actual mining roadway as the simulation object, two simulation schemes adopting the newly improved approach and the original method were conducted, respectively. The results show that (1) the PILE element that constitutes the rock bolt-free section with the maximum elongation rate ruptures after modification, while the rock bolt tendon elongation rate reaches beyond the predefined tensile rupture elongation rate; (2) the modified model in which the rock bolt is mainly subjected to tension realises the tensile rupture phenomenon at the end of the rock bolt-free section and the rock bolt at the junction between the free section and the anchoring section; and (3) only four rock bolts that are in the roadway sides showed rupture in the modified model, and all rock bolts showed rupture in the original model. The tensile failure of the rock bolt led that the modified model scheme is closer to the actual. Compared with the modified model, in the original model, deformation of the surrounding rock masses is severe. This is resulted by the rupture of all rock bolts in the original model. The analysis shows that the improved numerical simulation approach is much more reliable for large deformation roadway behavior with rock bolt support.

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Harris, Ruth A., and Steven M. Day. "Effects of a low-velocity zone on a dynamic rupture." Bulletin of the Seismological Society of America 87, no. 5 (October 1, 1997): 1267–80. http://dx.doi.org/10.1785/bssa0870051267.

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Abstract Dynamic-crack earthquake simulations generally assume that the crustal material surrounding faults is laterally homogeneous. Tomographic and near-fault seismic studies indicate that the crust near faults is instead comprised of rocks of varying material velocities. We have tested the effects of adding material-velocity variation to simulations of spontaneously propagating earthquakes. We used two-dimensional plane strain conditions coupled with a slip-weakening fracture criterion and examined earthquakes on faults that bisect finite-width low-velocity zones embedded in country rock and earthquakes on faults that bound two different-velocity materials. When a fault bisects a low-velocity zone, the normal stress remains unchanged, but both the rupture velocity and slip-velocity pulse shape are perturbed. The presence of the low-velocity zone induces high-frequency oscillations in the slip function near the rupture front. When the fault is on the edge of the low-velocity zone, the oscillations are more pronounced, and repeated sticking and slipping can occur near the rupture front. For the slip-weakening (velocity-independent) friction model, however, the temporary sticking does not lead to permanent arrest of slip, and slip duration is still controlled by the overall rupture dimension. When an earthquake ruptures a fault juxtaposing a lower-velocity material against a higher-velocity material, the normal stress across the fault near the crack tip is perturbed. The sign of the normal stress perturbation depends on the direction of rupture, leading in some cases to a directional dependence of rupture velocity. When slip is accompanied by stress reduction, a positive feedback develops between the normal and shear stress changes, as previously noted by Andrews and Ben-Zion (1997), resulting in an apparently unavoidable grid-size dependence in computation of stress change near the rupture front. Numerical experiments indicate, however, that the rupture velocity is insensitive to this zone size dependence, which is highly localized immediately behind the crack tip. The factors controlling the rupture velocity in the simulations, including directional dependence, are further elucidated by a new analytical solution for rupture of an asperity on a frictionless interface.

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Szalai, József. "Festigkeitstheorien von anisotropen Stoffen mit sprödem Bruchverhalten." Acta Silvatica et Lignaria Hungarica 4, no. 1 (January 1, 2008): 61–79. http://dx.doi.org/10.37045/aslh-2008-0007.

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Strength-theories of anisotropic materials with brittle rupture. Part 1: Comparison and adjudication of anisotropic strength-criterions by virtue of theoretical considerations. | The sizing of load-bearing anisotropic structures needs strength-criterion theories. Three of these hypothesises from the last century seem to be generally acceptable, so they are adaptable to all anisotropic materials in optional tensional status. A strength surface (a 6-dimensions hyper surface in the place of the stress-components) meets all theories. If they are tough materials, these surfaces can be only convex. Demonstrable – according the tests: the bunging surfaces with brittle rupture materials can content concave parts, too. The bunging relations can be transformed having one site supplementary potential or rather proportional expressions. In this interpretation the thesises of von Mises and of Tsai-Wu affirm the supplementary potential to bunging is constant and depends not on the orientation. The not reconcilable to this approach consequence is not followed by the Ashkenasitheory affirming the accumulated to the break supplementary potential is not constant, but depends on invariants of the stress state, mediately on orientation. These statements apply first of all to wood and wood-based materials, but can be extended to all anisotropic materials with brittle rupture.

28

Young, C. M. "Mediastinal assessment in traumatic rupture of the aorta." South African Journal of Radiology 1, no. 2 (May 31, 1996): 8–11. http://dx.doi.org/10.4102/sajr.v1i2.1612.

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The precise method for measuring mediastinal widening in thoracic trauma is poorly understood and too much emphasis is placed on it as the sole criterion for performing aortography. This review article describes the established methods of measurement and their limitations, and also discusses the importance of other signs pointing to aortic rupture such as blurring of the aortic knuckle and a subjective impression of mediastinal abnormality which are more helpful in determining the need for angiography.

29

Nazarov, V. V. "Review of the author’s own results obtained from mechanical testing of titanium alloys." Diagnostics, Resource and Mechanics of materials and structures, no. 2 (April 2022): 21–34. http://dx.doi.org/10.17804/2410-9908.2022.2.021-034.

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Experimental data obtained at different times by the author for various titanium alloys are collected in one place. The mechanical properties of the VT1-0 alloy at normal temperature, the creep and creep rupture of the VT5 and VT6 alloys at 650 °C, the secondary creep of the VT1-0 alloy under complex stress conditions at 550 °C are considered. The final values of strains observed either at the rupture time or at mechanical test termination are taken as a criterion for combining all these data.

30

Lonsdale, D., R. J. Browne, and P. E. J. Flewitt. "Methodology for selecting creep tests to establish multiaxial stress rupture criterion." Materials Science and Technology 8, no. 12 (December 1992): 1141–44. http://dx.doi.org/10.1179/mst.1992.8.12.1141.

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31

Gonzalez-Rodriguez, David, Lionel Guillou, François Cornat, Julie Lafaurie-Janvore, Avin Babataheri, Emmanuel de Langre, Abdul I. Barakat, and Julien Husson. "Mechanical Criterion for the Rupture of a Cell Membrane under Compression." Biophysical Journal 111, no. 12 (December 2016): 2711–21. http://dx.doi.org/10.1016/j.bpj.2016.11.001.

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32

Boey, Freddy Y. C., and S. H. Teoh. "Bending creep rupture analysis using a non-linear energy criterion approach." Materials Science and Engineering: A 123, no. 1 (January 1990): 13–19. http://dx.doi.org/10.1016/0921-5093(90)90204-g.

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33

Daga, Karan, Manish Taneja, and Narayanaswamy Venketasubramanian. "Small Intracranial Aneurysms and Subarachnoid Hemorrhage: Is the Size Criterion for Risk of Rupture Relevant?" Case Reports in Neurology 12, Suppl. 1 (December 14, 2020): 161–68. http://dx.doi.org/10.1159/000503094.

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The current understanding is that small intracranial aneurysms (<7 mm) are not at a significant risk for rupture. However, there have been several published series of rupture and subarachnoid hemorrhage from aneurysms <5 mm. Three cases of intracranial aneurysms rupturing at <3 mm are presented in this paper. Patient age ranged between 38 and 57 years. The aneurysms were located in different parts of the circulation in the brain. This case series highlights that the size criterion alone is not adequate when evaluating patients with unruptured brain aneurysms for observational follow-up or treatment.

34

Petrova, Lyudmila Evgenyevna, Tatyana Ulyanovna Kuzminykh, Igor Uryevich Kogan, and Ekaterina Vasilyevna Mikhalchenko. "Characteristics of clinical progress of vaginal delivery after cesarean section." Journal of obstetrics and women's diseases 61, no. 6 (December 15, 2012): 41–47. http://dx.doi.org/10.17816/jowd61641-47.

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The 982 cases of women with uterine scar after cesarean section were analyzed. Clinical criterion of uterine scar consistency is the “maturity” uterine cervix and greater response of uterine cervix to the delivery preparation. Characteristics of vaginal delivery after cesarean section clinical progress are the following: spontaneous labor onset (95,5 %), abnormal labor (11,9 %), premature rupture of membranes (46,4 %). Induction of labor caused increased the frequency of dystocia by a factor of 2, whereas risk of repeated cesarean section increased 2.3. Frequency of the uterine rupture in these labor cases was 0,73 %.

35

An, Zi Liang, Wei Xin Wang, Zi Ye Wang, and Yi Feng Tang. "Performance of 316L Stainless Steel Diffusion Welding during High Temperature Creep." Key Engineering Materials 837 (April 2020): 22–27. http://dx.doi.org/10.4028/www.scientific.net/kem.837.22.

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The creep and rupture test were carried out on a non-standard specimen of 316L stainless steel (316L-SS) diffused bonding joint. And the θ-projection model was used to analyze the minimum creep strain rate and the remaining life at 500°C/6 MPa when the creep strain is 0.2%. According to the test results, design criterion for the diffusion bonding component at high temperature is established. The rupture experimental results show that the remaining life extrapolated by Larsen-Miller equation is relatively consistent with that calculated by the θ project concept method.

36

Kruyt, N. P., and O. Millet. "An analytical theory for the capillary bridge force between spheres." Journal of Fluid Mechanics 812 (December 22, 2016): 129–51. http://dx.doi.org/10.1017/jfm.2016.790.

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An analytical theory has been developed for properties of a steady, axisymmetric liquid–gas capillary bridge that is present between two identical, perfectly wettable, rigid spheres. In this theory the meridional profile of the capillary bridge surface is represented by a part of an ellipse. Parameters in this geometrical description are determined from the boundary conditions at the three-phase contact circle at the sphere and at the neck (i.e. in the middle between the two spheres) and by the condition that the mean curvature be equal at the three-phase contact circle and at the neck. Thus, the current theory takes into account properties of the governing Young–Laplace equation, contrary to the often-used toroidal approximation. Expressions have been developed analytically that give the geometrical parameters of the elliptical meridional profile as a function of the capillary bridge volume and the separation between the spheres. A rupture criterion has been obtained analytically that provides the maximum separation between the spheres as a function of the capillary bridge volume. This rupture criterion agrees well with a rupture criterion from the literature that is based on many numerical solutions of the Young–Laplace equation. An expression has been formulated analytically for the capillary force as a function of the capillary bridge volume and the separation between the spheres. The theoretical predictions for the capillary force agree well with the capillary forces obtained from the numerical solutions of the Young–Laplace equation and with those according to a comprehensive fit from the literature (that is based on many numerical solutions of the Young–Laplace equation), especially for smaller capillary bridge volumes.

37

Bacaria, Jean-Louis, Olivio Dalverny, Olivier Pantalé, and Roger Rakotomalala. "Transient Numerical Models of Metal Cutting using the Johnson-Cook's Rupture Criterion." International Journal of Forming Processes 5, no. 1 (March 30, 2002): 53–70. http://dx.doi.org/10.3166/ijfp.5.53-70.

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38

Limon, Roger, and Sylvie Lehmann. "A creep rupture criterion for Zircaloy-4 fuel cladding under internal pressure." Journal of Nuclear Materials 335, no. 3 (December 2004): 322–34. http://dx.doi.org/10.1016/j.jnucmat.2004.07.039.

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39

Yu, Jian Liang, Xing Qing Yan, and Ling Chen. "Finite Element Simulation on Failure of Elbow Impacted by Flat-Nosed Missile." Applied Mechanics and Materials 105-107 (September 2011): 38–42. http://dx.doi.org/10.4028/www.scientific.net/amm.105-107.38.

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Finite element model of the elbow interiorly impacted by flat-nosed missile was established using ANSYS/LS-DYNA. The Cowper-Symonds model was adopted. The rupture strain failure criterion was used to define the failure process. Numerical values were compared with experimental values obtained from the literature and the reliability of model was validated. The penetration failure mode of the elbow was analyzed. Factors of the critical rupture kinetic energy Er were acquired. It can be seen that the penetration failure mode is plugging induced by the extrusion and scraping dominated of axis stress. The effect of Do on Er can be neglected. Er increases with the increase of t/Do, Dm/t and R/Do when the missile mass m is invariable. The effect of m on Er should consider the factors of m and critical rupture velocity Vr.

40

Bache, D. H. "From rupture to structure: the physical character of flocs." Water Science and Technology 50, no. 12 (December 1, 2004): 55–62. http://dx.doi.org/10.2166/wst.2004.0695.

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The paper focuses on the physical character of flocs. This is developed through analysis of the impact of hydrodynamic stress on floc size. Theory is developed on the basis of an energy criterion which balances the turbulent kinetic energy against the energy expenditure associated with rupture. For turbulence, the kinetic energy per unit volume is modelled by the velocity scale (νɛ)1/4 and the d/η ratio in which ν, ɛ, η refer to the kinematic viscosity, the rate of energy dissipation per unit mass and the Kolmogorov length respectively. The distance scale, d, is equivalent to the maximum floc size. In its most rudimentary form, floc structure is based on the model S ∝ kφ/d3 in which k is the number of bonds broken and φ the potential energy expenditure per bond broken. With appropriate development, this transforms to S = So(d/do)D−3 in which do is the primary particle size, D - the fractal dimension, and So - a scaling factor controlling the mechanical strength. From the energy criterion, analytical expressions are derived for d in the form d = γɛ−m/2 in which γ and m are constants. Beside the proposal of a model for S, a valuable advance is the development of rupture theory for the continuous domain of d/η consistent with the Kolmogorov description of turbulence. Theory is compared with a number of published data sets in which there exists knowledge of parameters γ, m and D. The paper demonstrates how the model can be used as an analytical tool for dissecting the factors such as raw water quality or floc aids which control So.

41

Xie, Weiyun, Katsumi Hattori, Peng Han, and Haixia Shi. "Temporal Variation of b Value with Statistical Test in Wenchuan Area, China Prior to the 2008 Wenchuan Earthquake." Entropy 24, no. 4 (March 31, 2022): 494. http://dx.doi.org/10.3390/e24040494.

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The Gutenberg–Richter b value describes the ratio between large and small events. A number of studies have suggested that the b value decreases before large earthquakes. In this study, we investigate the temporal variation of the b value of an area along the main rupture zone of the 2008 Wenchuan earthquake (M8.0) prior to the great event. Before estimating b values, we tested the earthquake catalog to make sure that we use the reliable frequency–magnitude distribution by the calculation of MC (completeness of magnitude). We define parameter P (ΔAIC ≧ 2) values to examine the significance level of b-value changes in the temporal variation by combining a boostrap method with Akaike’s Information Criterion (AIC). The b value in the main rupture zone shows a long-term decrease trend. We then focus on a smaller area where the initial rupture starts. The results show that b values significantly changed about 3 months before the 2008 Wenchuan earthquake in the initial rupture area, indicating that the b value has a potential capability to monitor and detect precursory phenomena of great earthquakes.

42

Cao, Zelin, Xiaxin Tao, Zhengru Tao, and Aiping Tang. "Kinematic Source Modeling for the Synthesis of Broadband Ground Motion Using the f‐k Approach." Bulletin of the Seismological Society of America 109, no. 5 (July 23, 2019): 1738–57. http://dx.doi.org/10.1785/0120180294.

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Abstract A procedure for building a kinematic source model is proposed in this article for the synthesis of broadband ground motion based on the frequency–wavenumber Green’s function. The spatial distribution of slip on the rupture plane is generated by combining asperity slip with random slip. A set of scaling laws recently updated for the global and local parameters of seismic sources is adopted. To characterize the temporal evolution of slip on the rupture plane, different rupture velocities, and rise times are first generated by considering the correlation with slip, and a source time function obtained by rupture dynamics is selected for each subsource. Then, the entire rupture process is set as the object to jointly determine the rise time and rupture velocity for a given slip distribution under the selection criterion that the entire rupture process should radiate the closest seismic energy to the expected energy. To reduce uncertainty, 30 spatiotemporal rupture processes for an earthquake scenario are realized to select a mean source model. To demonstrate the feasibility of the proposed source modeling approach, two California earthquakes, the Whittier Narrows earthquake and the Loma Prieta earthquake, are chosen as case studies. The performance of the obtained source models shows that our modeling approach is advantageous for estimating the size of the rupture plane, emphasizing the effect of asperity, and considering the correlation between temporal rupture parameters and slip. The bias values between the observed and synthetic pseudospectral accelerations are relatively small compared to those for the methods on the Southern California Earthquake Center broadband platform. The synthetics are further compared with the estimates from regional ground‐motion prediction equations for four scenario earthquakes with moment magnitudes of 6.0, 6.5, 7.0, and 7.5. Finally, the sensitivity of the synthetic motion to various rupture parameters is analyzed.

43

Ayatollahi, Majid R., Mahdi Heydari-Meybodi, Mohammad Dehghany, and Filippo Berto. "A New Criterion for Rupture Assessment of Rubber-Like Materials under Mode-I Crack Loading: The Effective Stretch Criterion." Advanced Engineering Materials 18, no. 8 (April 6, 2016): 1364–70. http://dx.doi.org/10.1002/adem.201600046.

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44

Pokrovskii, A. M., and Yu G. Matvienko. "A Fracture Criterion with Biaxial Constraints of Deformations along the Front of a Normal Rupture Crack." Проблемы машиностроения и надежности машин, no. 4 (July 1, 2023): 34–44. http://dx.doi.org/10.31857/s0235711923040107.

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In this article, a new fracture criterion is formulated for a normal rupture crack, the most common in practice, based on the assumption that the tangential stresses in the prefracture zone are equal to the local strength of the material. In this case, the size of the prefracture area and the local strength are determined taking into account the nonsingular Тхx and Тzz stresses included in the asymptotic stress distribution according to Williams and characterizing the two-dimensional local constraint of deformation along the crack front in three-dimensional bodies. An expression for the effective stress intensity factor is obtained. In addition to the classical stress intensity factor, it includes the ratios of the Тxx and Тzz stresses to the yield strength. This makes it possible to take into account the restriction of deformations in the transverse (due to Тxx stresses) and longitudinal (due to Тzz stresses) directions in the vicinity of the crack front. Verification of the developed software tools and the proposed fracture criterion has been carried out. Examples of the implementation of the developed criterion for assessing crack resistance of a plate stretched in one or two directions with a coaxial transverse crack are given.

45

Souto, Nelson, António Andrade-Campos, and Sandrine Thuillier. "Shape Optimization of the Conventional Simple Shear Specimen." Key Engineering Materials 554-557 (June 2013): 2156–64. http://dx.doi.org/10.4028/www.scientific.net/kem.554-557.2156.

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Shear tests of rectangular sample are widely used by the scientific community for characterizing the material behavior due to large strains obtained. However, for some hard metals, such as the dual-phase steel DP 980, premature rupture occurs in the vicinity of the grips. Due to this fact, the shape of the shear specimen is optimized in this work with the aim of maximizing the deformation achieved in the central part of the specimen without the occurrence of rupture near the grips. As the rupture occurs at the corners of the shear specimen only the boundaries are subjected to shape optimization. A representation with cubic splines is adopted for the definition of the boundaries geometry. The material is defined by Hill’s 1948 yield criterion combined with an isotropic hardening law. Two macroscopic rupture criteria are considered and an objective function approach based on the maximization of the shear strain average value is defined. For this study, a direct search optimization method is used for minimizing the objective function. The optimized geometries obtained for the different rupture criteria and different set of design variables are compared. The use of a larger number of design variables allows to obtain optimized geometries with higher average shear strain. The best specimen geometry shape allows increasing the maximum deformation of DP 980 steel to 1.05 without occurrence of rupture. In addition, the final specimen geometries show a concave shape for the boundaries which means that this kind of shape is the best one to delay the rupture in shear specimens.

46

Liu, B., R. Villavicencio, S. Zhang, and C. Guedes Soares. "A simple criterion to evaluate the rupture of materials in ship collision simulations." Marine Structures 54 (July 2017): 92–111. http://dx.doi.org/10.1016/j.marstruc.2017.03.006.

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47

Tanaka, Takeharu, Andreas Klenk, and Yasuhide Asada. "A flow rule based on Huddleston’s multiaxial rupture criterion as a yield function." Nuclear Engineering and Design 190, no. 1-2 (June 1999): 231–38. http://dx.doi.org/10.1016/s0029-5493(99)00008-4.

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48

Lopes, Carla V., Rui P. Cardoso, and Francisco Q. Melo. "Numerical modelling of the asymmetric behaviour of concrete." Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 234, no. 7 (May 6, 2020): 988–1000. http://dx.doi.org/10.1177/1464420720922574.

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This article analyses the conditions for the yield stress state of concrete subjected to generalised loads. For this purpose, a limit stress state criterion, initially developed for the assessment of magnesium and respective alloys, is here adapted and implemented as a simulation model to assess the structural integrity of concrete components. In fact, materials as magnesium and concrete exhibit a similar mechanical behaviour, presenting a non-symmetric limit state domain for biaxial stress combinations, where it is observed a considerably larger strength to yield or rupture in a compression stress state than in a tensile one. The Cazacu yield stress state criterion has shown to be an accurate and realistic model to define the ultimate strength, either of concrete and magnesium alloys, as mentioned. The Cazacu criterion was implemented in a finite element program as a ‘user-defined’ subroutine. The numerical validation of that criterion was carried out on adjusting its limit stress state points to corresponding ones obtained by experiments of standard tensile or compression tests of concrete test specimens.

49

Boncio, Paolo, Francesca Liberi, Martina Caldarella, and Fiia-Charlotta Nurminen. "Width of surface rupture zone for thrust earthquakes: implications for earthquake fault zoning." Natural Hazards and Earth System Sciences 18, no. 1 (January 19, 2018): 241–56. http://dx.doi.org/10.5194/nhess-18-241-2018.

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Abstract. The criteria for zoning the surface fault rupture hazard (SFRH) along thrust faults are defined by analysing the characteristics of the areas of coseismic surface faulting in thrust earthquakes. Normal and strike–slip faults have been deeply studied by other authors concerning the SFRH, while thrust faults have not been studied with comparable attention. Surface faulting data were compiled for 11 well-studied historic thrust earthquakes occurred globally (5.4 ≤ M ≤ 7.9). Several different types of coseismic fault scarps characterize the analysed earthquakes, depending on the topography, fault geometry and near-surface materials (simple and hanging wall collapse scarps, pressure ridges, fold scarps and thrust or pressure ridges with bending-moment or flexural-slip fault ruptures due to large-scale folding). For all the earthquakes, the distance of distributed ruptures from the principal fault rupture (r) and the width of the rupture zone (WRZ) were compiled directly from the literature or measured systematically in GIS-georeferenced published maps. Overall, surface ruptures can occur up to large distances from the main fault ( ∼ 2150 m on the footwall and ∼ 3100 m on the hanging wall). Most of the ruptures occur on the hanging wall, preferentially in the vicinity of the principal fault trace ( > ∼ 50 % at distances < ∼ 250 m). The widest WRZ are recorded where sympathetic slip (Sy) on distant faults occurs, and/or where bending-moment (B-M) or flexural-slip (F-S) fault ruptures, associated with large-scale folds (hundreds of metres to kilometres in wavelength), are present. A positive relation between the earthquake magnitude and the total WRZ is evident, while a clear correlation between the vertical displacement on the principal fault and the total WRZ is not found. The distribution of surface ruptures is fitted with probability density functions, in order to define a criterion to remove outliers (e.g. 90 % probability of the cumulative distribution function) and define the zone where the likelihood of having surface ruptures is the highest. This might help in sizing the zones of SFRH during seismic microzonation (SM) mapping. In order to shape zones of SFRH, a very detailed earthquake geologic study of the fault is necessary (the highest level of SM, i.e. Level 3 SM according to Italian guidelines). In the absence of such a very detailed study (basic SM, i.e. Level 1 SM of Italian guidelines) a width of ∼ 840 m (90 % probability from "simple thrust" database of distributed ruptures, excluding B-M, F-S and Sy fault ruptures) is suggested to be sufficiently precautionary. For more detailed SM, where the fault is carefully mapped, one must consider that the highest SFRH is concentrated in a narrow zone, ∼ 60 m in width, that should be considered as a fault avoidance zone (more than one-third of the distributed ruptures are expected to occur within this zone). The fault rupture hazard zones should be asymmetric compared to the trace of the principal fault. The average footwall to hanging wall ratio (FW : HW) is close to 1 : 2 in all analysed cases. These criteria are applicable to "simple thrust" faults, without considering possible B-M or F-S fault ruptures due to large-scale folding, and without considering sympathetic slip on distant faults. Areas potentially susceptible to B-M or F-S fault ruptures should have their own zones of fault rupture hazard that can be defined by detailed knowledge of the structural setting of the area (shape, wavelength, tightness and lithology of the thrust-related large-scale folds) and by geomorphic evidence of past secondary faulting. Distant active faults, potentially susceptible to sympathetic triggering, should be zoned as separate principal faults. The entire database of distributed ruptures (including B-M, F-S and Sy fault ruptures) can be useful in poorly known areas, in order to assess the extent of the area within which potential sources of fault displacement hazard can be present. The results from this study and the database made available in the Supplement can be used for improving the attenuation relationships for distributed faulting, with possible applications in probabilistic studies of fault displacement hazard.

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Jeldres, Matías, Luis Ayala, Pedro Robles, Edelmira Gálvez, Williams H. Leiva, Pedro G. Toledo, and Ricardo I. Jeldres. "A Criterion for Estimating the Strength of Flocculated Aggregates in Salt Solutions." Minerals 11, no. 7 (July 1, 2021): 713. http://dx.doi.org/10.3390/min11070713.

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A simple criterion is proposed to quantitatively estimate the resistance of aggregates based on incremental mechanical shear disturbances. Aggregate strength can be affected by the hydrodynamic conditions under which flocculation occurs; therefore, an experimental method is standardized to determine the resistance of aggregate structures that are formed under defined conditions of salinity (NaCl 0–0.1 M), mixing time (3 min), and mean shear rate (G = 273 s−1). Kaolin particles were flocculated in saline solutions with an anionic flocculant of high molecular weight. The method involves increasing the mean shear rate (G = 0–1516 s−1). Each increment represents a new experiment that starts from the base of 273 s−1. Target aggregates are increasingly fragmented as mechanical disturbance increases. The monotonic relationship between the mean shear rate increments (ΔG) and the final size of the aggregates is used for a quantitative estimate of the resistance of the target aggregates since this resistance underlies this relationship. The evolution of aggregate size is analyzed by the Focused Beam Reflectance Measurement (FBRM) method, which may capture the chord length distribution on concentrated slurries. To estimate and compare the resistance of the target aggregates in solutions with different salinities, a pseudo-first-order model that describes the rupture degree as a function of shear rate increments obtains the characteristic shear rate. The rupture percentage is reached with considerably lower agitation increments at higher salinity than at low salinity. This criterion is expected to help improve the efficiency of solid–liquid separation processes, especially in plants operating with seawater, be it raw or partially desalinated.

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