Journal articles: 'Static stress change'

1

Hardebeck, Jeanne L. "The impact of static stress change, dynamic stress change, and the background stress on aftershock focal mechanisms." Journal of Geophysical Research: Solid Earth 119, no. 11 (November 2014): 8239–66. http://dx.doi.org/10.1002/2014jb011533.

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Santos, Leandra, Yan Campo, Douglas da Silva, Thiago Burgo, and Fernando Galembeck. "Rubber Surface Change and Static Charging under Periodic Stress." Colloids and Interfaces 2, no. 4 (November 6, 2018): 55. http://dx.doi.org/10.3390/colloids2040055.

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Rubber materials play an important role in robotics, due to their sensing and actuating abilities, that are exploited in soft smart materials endowed with shape-adaptive and electroadhesive properties. The application of an electric field produces non-linear deformation that has been extensively modelled, but is not understood at the molecular level. The symmetric effect (the production of an electric field due to rubber deformation) was recently discovered and explained as follows: rubber surface chemical composition and adsorptive properties change during rubber deformation, allowing the surface to exchange charge with the atmosphere. The present work describes the complex surface morphology and microchemistry of tubing made from vulcanized natural rubber, showing that it is rough and made from two domain types: stiffer elevations containing Br or Al (depending on the sample used) and O, that rise above an elastic base that is exempt of elements other than C and H. The surface area fraction occupied by the elastic base is higher in the strained rubber than when it is relaxed. Electrostatic potential on rubber surfaces was measured as a function of the stretching frequency, using Kelvin electrodes and showing frequency-dependent potential variation. This is explained considering charge exchange between the atmosphere and rubber surface, mediated by water vapor adsorbed in the stretched rubber and trapped when it relaxes.

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Tsaplev, V. M., R. S. Konovalov, and S. I. Konovalov. "The Effect of Static Stress on the Anisotropy of Piezoceramics." Materials 15, no. 15 (July 26, 2022): 5186. http://dx.doi.org/10.3390/ma15155186.

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The influence of static compressional stress on the anisotropy of piezoelectric ceramics of BaTiO3 and PZT types is considered theoretically and experimentally. Static compression changes the domain structure of piezoceramics. These changes occur due to the reorientation of mostly 90° domain axes. As a result, all the parameters of the material change—elastic, piezoelectric, and dielectric. Some of them increase, and some, on the contrary, decrease. Changes occur in a nonlinear way, and higher-order parameters appear. The relationship between the total volume of the reoriented domains and the change in elastic moduli and piezomoduli is theoretically considered. The corresponding theoretical dependences are obtained. To confirm these theoretical dependences, experimental measurements were performed using the ultrasonic pulse-interference method at a frequency of 8 MHz. There is practically no oscillation movement of domain boundaries at this frequency, therefore, the change in the system of elastic and piezoelectric moduli is structural, not dynamic. The possibility of predicting changes in the structure of modules as a result of static compression is shown.

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Belmas, Ivan, Hanna Tantsura, Olena Bilous, Anhelina Shvachka, and Yuliana Gupalo. "Investigation of a static rope with a cable break." Strength of Materials and Theory of Structures, no. 108 (May 30, 2022): 349–59. http://dx.doi.org/10.32347/2410-2547.2022.108.349-359.

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Abstract. Establishing the influence of changes in the temporary properties of rubber on the stress state of the rubber traction body with a damaged cable. The method of research consists in the analytical solution of the model of the humorous traction body taking into account the rupture of the cable continuity and the change in the properties of the rubber. The dependences of the change of the stress state of the traction body of the humotross with the broken structure due to the rheology of the rubber shell are established. An algorithm for determining the stress state of a rubber traction body in case of its failure is formulated. It is shown that the loads on the ropes caused by the rupture of one of them lead to a local redistribution of forces almost only between two cables - damaged and adjacent; when damaged, non-extreme cable forces change in almost only three cables - damaged and two related. There are no extreme values of the internal load forces of the cables, which depend on the change of the shear modulus of the rubber material over time. Construction of a method for determining the influence of impulses of individual cables of a cable rubber rope on its stress state. Development and solution of the model of stress-strain state of the cable rubber rope with breaks in the continuity of the cables. Methods of determining the stress state of a cable rope with a damaged cable. The mechanism and nature of the influence of the impulses of the continuity of the cable of the cable rubber rope on its stress-strain state. The developed method allows to take into account the influence of cable bursts on the stress state of the humorous cable rope of arbitrary design. Its application will allow to reasonably determine the minimum reserves of strength under the condition of safe use of the rubber rope, including in case of rupture of individual cables. The mechanism of influence of change of properties of rubber on pressure is established by a condition of a traction body taking into account a rupture of continuity of a cable and change of properties of rubber. Taking into account the dependence of the stress-strain state of the rope with local violations of the cable base on changes in mechanical properties of rubber provides the ability to predict the stress state of the rope to improve safety and reliability of rubber traction with a long service life.

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Hardebeck, Jeanne L., and Ruth A. Harris. "Earthquakes in the Shadows: Why Aftershocks Occur at Surprising Locations." Seismic Record 2, no. 3 (July 1, 2022): 207–16. http://dx.doi.org/10.1785/0320220023.

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Abstract For decades there has been a debate about the relative effects of dynamic versus static stress triggering of aftershocks. According to the static Coulomb stress change hypothesis, aftershocks should not occur in stress shadows—regions where static Coulomb stress has been reduced. We show that static stress shadows substantially influence aftershock occurrence following three M ≥ 7 California mainshocks. Within the modeled static Coulomb stress shadows, the aftershock rate is an order of magnitude lower than in the modeled increase regions. However, the earthquake rate in the stress shadows does not decrease below the background rate, as predicted by Coulomb stress change models. Aftershocks in the stress shadows exhibit different spatial–temporal characteristics from aftershocks in the stress increase regions. The aftershock rate in the stress shadows decays as a power law with distance from the mainshock, consistent with a simple model of dynamic stress triggering. These aftershocks begin with a burst of activity during the first few days after the mainshock, also consistent with dynamic stress triggering. Our interpretation is that aftershock sequences are the combined result of static and dynamic stress triggering, with an estimated ∼34% of aftershocks due to dynamic triggering and ∼66% due to static triggering.

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Li, Xian-Fang, and L. Roy Xu. "T-Stresses Across Static Crack Kinking." Journal of Applied Mechanics 74, no. 2 (January 20, 2006): 181–90. http://dx.doi.org/10.1115/1.2188016.

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This paper is concerned with the T-stress change before and after crack kinking in two-dimensional elastic solids. By using asymptotic analysis and the Westergaard stress function method, approximate analytical formulas for calculating the T-stress as well as stress intensify factors of an infinitesimal kink are given. Contributions from the T-stress before crack kinking, to the T-stress and the stress intensity factors of the kinked crack, are clearly described. It is noted that since the sign of the T-stress of a kinked open crack might be different from that of a main crack, simply using the sign of the T-stress before crack kinking is not sufficient to determine crack growth stability as observed in recent experiments.

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Caskey, S. J., and S. G. Wesnousky. "Static stress changes and earthquake triggering during the 1954 Fairview Peak and Dixie Valley earthquakes, central Nevada." Bulletin of the Seismological Society of America 87, no. 3 (June 1, 1997): 521–27. http://dx.doi.org/10.1785/bssa0870030521.

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Abstract The 16 December 1954 Dixie Valley (MS 6.8) earthquake followed the Fairview Peak (MS 7.2) earthquake by only 4 min and 20 sec. A three-dimensional model of the two dip-slip fault systems based on recent detailed field studies shows the ruptures were separated by a 6-km step in surface trace. A boundary-element approach shows that the static stress changes imposed by rupture of the Fairview Peak earthquake are in the correct sense to explain the northward propagation of faulting along four distinct faults that comprise the Fairview Peak earthquake and the subsequent triggering of the Dixie Valley earthquake. The location of rupture end points at sites where static stresses change sign is also used to suggest that static stress changes may play a role in controlling the extent of fault ruptures. We also observe that the largest coseismic surface displacements tend to correlate with those sections of the faults showing the largest positive stress change from preceding ruptures.

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Parsons, Tom, Yosihiko Ogata, Jiancang Zhuang, and Eric L. Geist. "Evaluation of static stress change forecasting with prospective and blind tests." Geophysical Journal International 188, no. 3 (January 25, 2012): 1425–40. http://dx.doi.org/10.1111/j.1365-246x.2011.05343.x.

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Liu, Yu, Rui Jing, and Peiyu Yan. "Effects of Mineral Admixtures on the Evolution of Static Yield Stress of Different Composite Pastes." Processes 11, no. 2 (February 17, 2023): 614. http://dx.doi.org/10.3390/pr11020614.

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The effects of different mineral admixtures on the evolution of static yield stress of common composite cementitious material paste and ultra-high-performance concrete (UHPC)-based paste were investigated. The results show that there are obvious differences in the role of mineral admixtures in the common paste and the UHPC-based paste. Adding mineral admixtures can change the initial static yield stress of the paste by affecting the particle size, particle shape and the charged particles. The addition of mineral admixtures with small particle size such as silica fume and ultrafine slag can increase the initial static yield stress of common paste but reduce that of UHPC-based paste. Adding mineral admixtures changes the evolution of static yield stress of the paste by affecting the particle spacing and the formation and growth rate of hydration products. In turn, the addition of ultrafine slag or silica fume increases the growth of the static yield stress of common paste. Adding slag, fly ash or fly ash microbeads successively reduces the static yield stress of common paste at the later stage. Affected by the content of PCE, the static yield stress of UHPC-based paste containing fly ash microbeads, slag, ultrafine slag and fly ash increases sequentially compared with the blank group at the later stage. The effect of silica fume with different dosages on the evolution of static yield stress of UHPC-based paste is significantly different.

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Jiménez-Donaire, María del Pilar, Juan Vicente Giráldez, and Tom Vanwalleghem. "Impact of Climate Change on Agricultural Droughts in Spain." Water 12, no. 11 (November 17, 2020): 3214. http://dx.doi.org/10.3390/w12113214.

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Drought is an important natural hazard that is expected to increase in frequency and intensity as a consequence of climate change. This study aimed to evaluate the impact of future changes in the temperature and precipitation regime of Spain on agricultural droughts, using novel static and dynamic drought indices. Statistically downscaled climate change scenarios from the model HadGEM2-CC, under the scenario representative concentration pathway 8.5 (RCP8.5), were used at a total of 374 sites for the period 2006 to 2100. The evolution of static and dynamic drought stress indices over time show clearly how drought frequency, duration and intensity increase over time. Values of static and dynamic drought indices increase over time, with more frequent occurrences of maximum index values equal to 1, especially towards the end of the century (2071–2100). Spatially, the increase occurs over almost the entire area, except in the more humid northern Spain, and in areas that are already dry at present, which are located in southeast Spain and in the Ebro valley. This study confirms the potential of static and dynamic indices for monitoring and prediction of drought stress.

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Li, Zhen. "Study on the Sealing Performance of O-ring under High-Pressure Environment." Journal of Physics: Conference Series 2419, no. 1 (January 1, 2023): 012005. http://dx.doi.org/10.1088/1742-6596/2419/1/012005.

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Abstract The sealing properties of the O-ring of the hydraulic cylinder plunger rod under a high-pressure environment are related to a variety of factors. In this paper, we first establish a simulation model based on an O-ring reciprocating shaft seal under a high pressure-environment through finite element software and study the influence of the compression rate, static pressure, and reciprocating speed of the plunger rod on the sealing performance of O-ring through the simulation model, and then analyze the maximum stress of O-ring during installation, hydrostatic loading and reciprocating motion with the variation of structural parameters. The results indicate that the compression rate of the installation process has a significant effect on the sealing performance of the enhanced O-ring. In the hydrostatic loading process, the equivalent stress of the O-ring is increased with the increase of the compression rate, when the static pressure is low and decreases, and when the static pressure is high, and the equivalent stress shows an increasing trend and the same increase; in the reciprocating motion process, when the static pressure is low, the equivalent stress and contact stress of the O-ring does not change significantly with the compression rate, and when the static pressure is high, there is an obvious phenomenon of abrupt change. The frictional stress of the reciprocating motion is increasing, then decreases, and then increases with the change in static pressure.

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Sun, You Wei, Ni Men, Jing Shan Bo, Ping Li, and Xiao Guang Cai. "Analysis of Tunnel Rock’s Dynamic Stress with Input of Different Peak Ground Motions." Advanced Materials Research 378-379 (October 2011): 218–21. http://dx.doi.org/10.4028/www.scientific.net/amr.378-379.218.

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The changes of tunnel rock stress caused by dynamic load is a hot point in geotechnical engineering. The paper introduces seismic methods of seismic design codes in China. The paper select state road 318(Huangcaoping part)as an example. Using finite difference software to analyze the rock pressure changes around the lining-tunnel with different seismic inputs. Comparing the results the rock static pressure and find the relative amplification factor between dynamic pressure and static pressure. Based on the results of analysis, we can obtain the following conclusions: As the peak ground motion acceleration increases, the peak value of tunnel rock increases, too. The amplifications change in a small range. The oblique parts of tunnel are the weakest parts of the tunnels. In different areas, the amplifications change a lot. The maximum ones are in the area of oblique.

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Wang, Gen Li, Zheng Mao Ye, and Bin Wu. "The Change of Stress on Marine Concrete Covered with Barnacles." Applied Mechanics and Materials 584-586 (July 2014): 1031–34. http://dx.doi.org/10.4028/www.scientific.net/amm.584-586.1031.

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Barnacle is a major creature in marine fouling organisms, it increases static load and dynamic load of marine structures. In this paper, the change of stress on marine concrete surface covered with barnacles is studied. Moreover, a simplified model is established. The result shows that the stress of seawater increases by 0.53 times on the concrete surface, which is covered with barnacles.

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TONE, Shigeyasu, Takashi MIYATAKE, Kazuhito HIKIMA, and Aitaro KATO. "Change of Static Stress Fields from Earthquake Rupture in Heterogeneous Crustal Structure." Zisin (Journal of the Seismological Society of Japan. 2nd ser.) 62, no. 2/3 (2009): 97–107. http://dx.doi.org/10.4294/zisin.62.97.

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Liu, Lei, Xiang Meng, Hao Qin, and Zhaozhao Chang. "Experimental Research on the Influence of Temperature on the Static Properties of Skarn." Advances in Civil Engineering 2021 (April 8, 2021): 1–13. http://dx.doi.org/10.1155/2021/6636775.

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Studying the high-temperature mechanical properties of rocks is of great significance to engineering disasters caused by deep rock mining and underground protection projects. In view of insufficient research on the high-temperature mechanical properties of deep rocks in southwestern China, we used high-temperature heating devices and statics equipment to conduct static tests on Skarn. XW7L-12 box-type resistance furnace was adopted to heat Skarn (25°C, 200°C, 400°C, 600°C, and 800°C), and the temperature effect of its basic physical parameters (density and wave velocity) was measured and analyzed. Uniaxial compression experiments were performed on two cooling methods of Skarn (natural cooling and water cooling) by a constant stress pressure testing machine to obtain a stress-strain curve and analyze its statics index (peak strength, tensile strength, elastic modulus, and peak strain) and the change rule of failure mode with temperature rise and different cooling methods. With the temperature increasing, various static mechanical indexes of Skarn will be greatly affected. Meanwhile, the different cooling methods are not related to the change trend of the mechanical properties of Skarn under high temperature.

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Mignan, A. "Static behaviour of induced seismicity." Nonlinear Processes in Geophysics Discussions 2, no. 6 (December 10, 2015): 1659–74. http://dx.doi.org/10.5194/npgd-2-1659-2015.

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Abstract. The standard paradigm to describe seismicity induced by fluid injection is to apply nonlinear diffusion dynamics in a poroelastic medium. I show that the spatiotemporal behaviour and rate evolution of induced seismicity can, instead, be expressed by geometric operations on a static stress field produced by volume change at depth. I obtain laws similar in form to the ones derived from poroelasticity while requiring a lower description length. Although fluid flow is known to occur in the ground, it is not pertinent to the behaviour of induced seismicity. The proposed model is equivalent to the static stress model for tectonic foreshocks generated by the Non-Critical Precursory Accelerating Seismicity Theory. This study hence verifies the explanatory power of this theory outside of its original scope.

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Fujita, Eisuke, Tomofumi Kozono, Norio Toda, Aiko Kikuchi, and Yoshiaki Ida. "Quasi-Static Stress Change Around Mount Fuji Region Due to Tohoku Mega-Thrust Earthquake." Journal of Disaster Research 9, no. 3 (June 1, 2014): 365–72. http://dx.doi.org/10.20965/jdr.2014.p0365.

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The 2011 Tohoku mega-thrust earthquake caused huge crustal deformation over a wide are of Mainland Japan. Many mega-thrust earthquakes worldwide have triggered volcanic eruptions nearby, and it is assumed that stress changes due to the Tohoku earthquake resulted in a perturbation to the magma system. The objectives of our study is to evaluate this perturbation quantitatively and to analyze the mechanism of the interaction between mega-thrust earthquakes and volcanic eruptions. This paper focuses on quasi-static stress change due to viscous relaxation of a source region and the surrounding area.

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Mignan, Arnaud. "Static behaviour of induced seismicity." Nonlinear Processes in Geophysics 23, no. 2 (April 29, 2016): 107–13. http://dx.doi.org/10.5194/npg-23-107-2016.

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Abstract. The standard paradigm to describe seismicity induced by fluid injection is to apply non-linear diffusion dynamics in a poroelastic medium. I show that the spatio-temporal behaviour and rate evolution of induced seismicity can, instead, be expressed by geometric operations on a static stress field produced by volume change at depth. I obtain laws similar in form to the ones derived from poroelasticity while requiring a lower description length. Although fluid flow is known to occur in the ground, it is not pertinent to the geometrical description of the spatio-temporal patterns of induced seismicity. The proposed model is equivalent to the static stress model for tectonic foreshocks generated by the Non-Critical Precursory Accelerating Seismicity Theory. This study hence verifies the explanatory power of this theory outside of its original scope and provides an alternative physical approach to poroelasticity for the modelling of induced seismicity. The applicability of the proposed geometrical approach is illustrated for the case of the 2006, Basel enhanced geothermal system stimulation experiment. Applicability to more problematic cases where the stress field may be spatially heterogeneous is also discussed.

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Hardebeck, Jeanne L., Julie J. Nazareth, and Egill Hauksson. "The static stress change triggering model: Constraints from two southern California aftershock sequences." Journal of Geophysical Research: Solid Earth 103, B10 (October 10, 1998): 24427–37. http://dx.doi.org/10.1029/98jb00573.

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SHI, Yao-Lin, and Jian-Ling CAO. "Some Aspects of Static Stress Change Calculation-Case Study on the Wenchuan Earthquake." Chinese Journal of Geophysics 53, no. 1 (January 2010): 64–73. http://dx.doi.org/10.1002/cjg2.1473.

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Bathija, Arpita Pal, Michael Lee Batzle, and Manika Prasad. "An experimental study of the dilation factor." GEOPHYSICS 74, no. 4 (July 2009): E181—E191. http://dx.doi.org/10.1190/1.3137060.

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Dilation factor [Formula: see text] is the ratio of relative change in velocity to relative change in deformation (strain). It has significant implications for 4D seismic studies where it can be used to infer reservoir or overburden thickness changes from seismic changes, but the effect of stress on [Formula: see text] and its components is not well understood. We conduct static strain and ultrasonic velocity measurements to study the effect of stress on [Formula: see text] and its components. Measured absolute [Formula: see text] values (6–91 in sandstones and 6–11 in shale) depend on the deformation mechanisms causing the strain. The dynamic (low-amplitude) Young’s modulus generally is higher than the static (high-amplitude) Young’s modulus. Hence, theoretical models that use the same mechanism to describe wave propagation and macroscopic deformation are invalid. The ratio of dynamic to static modulus depends on the direction of stress applied with respect to the density and placement of cracks. Values of [Formula: see text] differ for P- and S-waves, especially in the presence of fluids. The values also depend strongly on the stress states; hence, using a constant value of [Formula: see text] from the surface to reservoir depth should be avoided. Absolute [Formula: see text] values increase for sandstones and decrease for shales with decreasing confining pressure, which explains the low [Formula: see text] values from 4D seismic data. Our data offer insight into the behavior of [Formula: see text] values with different rock types, stress, and fluid, and they can be used to constrain model calculations.

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Nalbant, Suleyman S., Sandy Steacy, and John McCloskey. "Stress transfer relations among the earthquakes that occurred in Kerman province, southern Iran since 1981." Geophysical Journal International 167, no. 1 (October 1, 2006): 309–18. http://dx.doi.org/10.1111/j.1365-246x.2006.03119.x.

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Summary We explore the possible stress triggering relationship of the M≥ 6.4 earthquakes that occurred in Kerman Province, southern Iran since 1981. We calculated stress changes due to both coseismic sudden movement in the upper crust and the time-dependent viscous relaxation of the lower crust and/or upper mantle following the event. Four events of M≥ 6.4 occurred between 1981 and 2005, on and close to the Gowk fault, show a clear Coulomb stress load to failure relationship. The 2003 M= 6.5 Bam earthquake, however, which occurred approximately 95 km SW of the closest Gowk event, shows a very weak stress relation to preceding earthquakes. The coseismic static stress change at the hypocentre of the Bam earthquake is quite small (∼0.006 bars). The time-dependent post-seismic stress change could be 26 times larger or 7 times lower than that of coseismic static stress alone depending on the choice of viscoelastic crustal model and the effective coefficient of friction. Given the uncertainties in the viscoelastic earth models and the effective coefficient of friction, we cannot confidently conclude that the 2003 Bam event was brought closer to failure through coseismic or post-seismic stress loading. Interestingly, the southern Gowk segment with a similar strike to that of the Bam fault, experienced a stress load of up to 8.3 bars between 1981 and 2003, and is yet to have a damaging earthquake.

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Yunshan, Han, Wu Han, Dong Yanli, and Wang Yuanlong. "Evaluation of Overall Stability for Garage Foundation Excavation of High Buildings." Open Civil Engineering Journal 9, no. 1 (September 30, 2015): 757–62. http://dx.doi.org/10.2174/1874149501509010757.

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In current projects, many garages were built after the main structure finished. However, the excavation of garage foundation not only changed the bearing capacity modification by depth, but also makes the soil pressure along the two sides become different. And thus the stress condition of the main building foundations is changed. The change of stress condition affects the stability of main structure directly. Based on the stress condition of high buildings foundation after one side excavation, the change of settlement under the eccentric action was studied. The change of settlement makes the tilt turning appear and thus makes the overturning resistance moment change. The dynamic principle of stability safety factors were also investigated in this paper. The effect of settlement affected by the change of stress condition was considered in the stability analysis of high building. This new method can better and truly evaluate the effect of excavation of foundation on the stability of overturning resistance than the traditional method considering only the static load-carrying capability. The operation of the new method is stronger in the project application for its clear mechanism.

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Segou, Margarita, and Tom Parsons. "A New Technique to Calculate Earthquake Stress Transfer and to Probe the Physics of Aftershocks." Bulletin of the Seismological Society of America 110, no. 2 (February 11, 2020): 863–73. http://dx.doi.org/10.1785/0120190033.

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ABSTRACT Coseismic stress changes have been the primary physical principle used to explain aftershocks and triggered earthquakes. However, this method does not adequately forecast earthquake rates and diverse rupture populations when subjected to formal testing. We show that earthquake forecasts can be impaired by assumptions made in physics-based models such as the existence of hypothetical optimal faults and regional scale invariability of the stress field. We compare calculations made under these assumptions along with different realizations of a new conceptual triggering model that features a complete assay of all possible ruptures. In this concept, there always exists a set of theoretical planes that has positive failure stress conditions under a combination of background and coseismic static stress change. In the Earth, all of these theoretical planes may not exist, and if they do, they may not be ready to fail. Thus, the actual aftershock plane may not correspond to the plane with the maximum stress change value. This is consistent with observations that mainshocks commonly activate faults with exotic orientations and rakes. Our testing ground is the M 7.2, 2010 El Mayor–Cucapah earthquake sequence that activated multiple diverse fault populations across the United States–Mexico border in California and Baja California. We carry out a retrospective test involving 748 M≥3.0 triggered earthquakes that occurred during a 3 yr period after the mainshock. We find that a probabilistic expression of possible aftershock planes constrained by premainshock rupture patterns is strongly favored (89% of aftershocks consistent with static stress triggering) versus an optimal fault implementation (35% consistent). Results show that coseismic stress change magnitudes do not necessarily control earthquake triggering, instead we find that the summed background stress and coseismic stress change promotes diverse ruptures. Our model can thus explain earthquake triggering in regions where optimal plane mapping shows coseismic stress reduction.

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Ohya, Shin'ichi, and Shozaburo Ohta. "Time-Resolved X-ray Stress Measurement During Cyclic Loading." Advances in X-ray Analysis 33 (1989): 335–40. http://dx.doi.org/10.1154/s0376030800019741.

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X-ray stress analysis is widely used in the measurement of residual stress or stress under static loading. If it is possible to measure actual stress at any applied stress level during cyclic loading by using x-rays, it will be of much help in investigating dynamical fatigue behavior such as crack closure and change of residual stress distribution.

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Xiao, Yang, Shengyu Hou, Shuling Dai, Xinfeng Xu, and Jie Zhang. "Dynamic Simulation and Analysis of Engagement Process for Logarithmic Spiral Bevel Gear Based on Accurate 3D Model." Journal of Physics: Conference Series 2179, no. 1 (January 1, 2022): 012001. http://dx.doi.org/10.1088/1742-6596/2179/1/012001.

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Abstract Based on the accurate 3D model of logarithmic spiral bevel gear, the operation of spiral cone gear engagement is analyzed and simulated by ANSYS. Through the nonlinear static contact analysis of different positions, the stress change rule and the maximum contact stress is obtained. Compared with the theoretical contact stress strength rule, this paper also analyzes the dynamic operation situation of the gear pairs, obtains the dynamic contact situation rule at different engagement times and different rotating speeds, the influence of the rotating speed on the gear contact characteristics is compared too. The static, dynamic performance and change rules of the gear engagement is obtained, which lay a solid foundation for the further research, design and manufacture of spiral bevel gears.

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Westerberg, Kristina, and Susanne Tafvelin. "Changes in commitment to change among leaders in home help services." Leadership in Health Services 28, no. 3 (July 6, 2015): 216–27. http://dx.doi.org/10.1108/lhs-04-2014-0038.

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Purpose – The purpose of the this study was to explore the development of commitment to change among leaders in the home help services during organizational change and to study this development in relation to workload and stress. During organizational change initiatives, commitment to change among leaders is important to ensure the implementation of the change. However, little is known of development of commitment of change over time. Design/methodology/approach – The study used a qualitative design with semi-structured interviews with ten leaders by the time an organizational change initiative was launched and follow-up one year later. Thematic content analysis was used to analyze the interviews. Findings – Commitment to change is not static, but seems to develop over time and during organizational change. At the first interview, leaders had a varied pattern reflecting different dimensions of commitment to change. One year later, the differences between leaders’ commitment to change was less obvious. Differences in commitment to change had no apparent relationship with workload or stress. Research limitations/implications – The data were collected from one organization, and the number of participants were small which could affect the results on workload and stress in relation to commitment to change. Practical implications – It is important to support leaders during organizational change initiatives to maintain their commitment. One way to accomplish this is to use management team meetings to monitor how leaders perceive their situation. Originality/value – Qualitative, longitudinal and leader studies on commitment to change are all unusual, and taken together, this study shows new aspects of commitment.

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Kwaśniewski, Janusz, Ireneusz Dominik, Krzysztof Lalik, and Rafał Szymański. "Harmonic Analysis of Self-Excited Acoustical System for Stress Changes Measurement in Compressed Steel Structural Section." Solid State Phenomena 198 (March 2013): 639–44. http://dx.doi.org/10.4028/www.scientific.net/ssp.198.639.

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This paper presents the application of the Self-exited Acoustical System (SAS) for monitoring stress changes in steel. The change of the speed of wave propagation, which is associated with the change of the resonance frequency in the system is caused by the deformation of the examined material. The SAS system is based on this phenomenon and can be used for an indirectly measurement of the stresses changes in the steel. Preliminary calculations such as static analysis and dynamic simulation of the system were carried out. The results of calculations were compared with the experimental data of the steel beam.

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Bonali, F. L. "Earthquake-induced static stress change on magma pathway in promoting the 2012 Copahue eruption." Tectonophysics 608 (November 2013): 127–37. http://dx.doi.org/10.1016/j.tecto.2013.10.006.

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30

Yan, Fuyong, De-Hua Han, and Xue-Lian Chen. "Simultaneous static and dynamic bulk modulus measurements under hydrostatic stress conditions and without applying strain gauge." GEOPHYSICS 85, no. 4 (April 30, 2020): MR191—MR199. http://dx.doi.org/10.1190/geo2019-0390.1.

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The static properties of subsurface rocks are needed for geomechanical applications, but the dynamic properties are usually more extensively available and can be acquired with much less effort. Therefore, it is important to know the relationships between the static and dynamic properties. Studying these relationships based on traditional triaxial testing yields confusing results, partly due to intrinsic deficiencies of the experimental setup and testing procedures. We have developed a new approach to study the relationship under hydrostatic stress conditions. The traditional ultrasonic velocity measurement system is sufficient for all of the testing, and it requires no application of the traditional strain gauge. During the pressure-dependent ultrasonic velocity measurements, the rock sample experiences static deformation when the pressure changes are in the order of megapascals. If the pore pressure is kept constant, the pore volume will vary with the confining pressure. The pore volume change can be monitored accurately by the pore pressure controlling pump, and it can be related to the volume strain of the rock for estimating the static bulk modulus of the rock sample. Based on the laboratory ultrasonic measurements available in the literature, we analyzed the effects of the differential pressure, clay content, crack density, and pore fluid on the relationship between the static and dynamic bulk moduli. From the analyses, we inferred that most of the laboratory-observed differences between the static and dynamic property may not exist for the reservoir rock under in situ conditions.

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Utkucu, Murat, and Hatice Durmuş. "Usefulness of Coulomb Static Stress Changes in Earthquake Hazard Studies: An Example from the Lake Van Area, Eastern Turkey." Academic Perspective Procedia 4, no. 2 (November 6, 2021): 33–41. http://dx.doi.org/10.33793/acperpro.04.02.23.

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It has been globally documented over different tectonic environments that Coulomb static stress changes caused by a mainshock can promote or demote stresses along the neighboring faults and thus triggers or delays following seismicity. In the present study Coulomb stress changes of the earthquakes in the Lake Van area are calculated using available data and the likely source faults. The calculated stress change maps demonstrate that the large earthquakes in the Lake Area are mostly stressed by the preceding earthquakes, suggesting earthquake rupture interactions. It is further suggested that Coulomb stress maps could be used for constraining the likely locations of the future large earthquakes and in the earthquake hazard mitigation studies.

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Lou, Jia Jia, Xue Mei Cao, and Ji Song Jiao. "Tooth Surface Contact Stress Analysis of the Straight Bevel Gear Axial Practice." Applied Mechanics and Materials 401-403 (September 2013): 345–49. http://dx.doi.org/10.4028/www.scientific.net/amm.401-403.345.

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The program of tooth surface and gear inside grid nodes is developed according to the tooth surface equation. Finite Element Analysis of the straight bevel gear axial practice model is established. Order flow contact models of the three teeth and contact pair of gears of the three teeth is developed by APDL language of ANSYS. The static contact stress analysis of axial practice is constructed. The static contact stress of tooth surface distribution and change rule is obtained by calculating. The result shows that axial practice pair of gears of have good meshing performance.

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Ding, Ming Bo, and Xing Chong Chen. "Model Test Research on the Pile Stress by Pseudo-Static Test of Pier-Foundation-Structure System." Advanced Materials Research 383-390 (November 2011): 6641–45. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.6641.

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This paper mostly studied on the pile stress in the loess foundation when the pile and the soil are interacting by pseudo-static test of piers and piles in the remolded loess foundation indoor. We get the stress-depth curve of pile body. We get its finite element model by ANASYS and analyze the change of pile body stress.

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34

Yamamoto, Ei, Wataru Iwanaga, Hiroshi Miyazaki, and Kozaburo Hayashi. "Effects of Static Stress on the Mechanical Properties of Cultured Collagen Fascicles From the Rabbit Patellar Tendon." Journal of Biomechanical Engineering 124, no. 1 (August 16, 2001): 85–93. http://dx.doi.org/10.1115/1.1427924.

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In-vitro tissue culture experiments were performed to study the effects of static stress on the mechanical properties of collagen fascicles obtained from the rabbit patellar tendon. After collagen fascicles having the diameter of approximately 300 μm were cultured for 1 and 2 wk under static stress between 0 and 3 MPa, their mechanical properties and crimp morphology were determined using a micro-tensile tester and a light microscope, respectively. The tensile strength and tangent modulus of the fascicles were significantly decreased by culture under no load compared to control fascicles. A statistically significant correlation, which was described by a quadratic curve, was observed between applied stress and tensile strength. The maximum tensile strength (16.7 MPa) was obtained at the applied stress of 1.2 MPa; the strength was within a range of control values. There was a similar correlation between applied stress and tangent modulus, and the modulus was maintained at control level under 1.3 MPa stress. The stress of 1.2 to 1.3 MPa is equivalent to approximately 50 percent of the peak stress developed in the intact rabbit patellar tendon by running. Strain at failure of cultured collagen fascicles was negatively correlated with applied stress, and that at 1.2 to 1.3 MPa stress was almost the same as the control value. Crimp morphology in the fascicles cultured under about 1.2 MPa stress was similar to that in control fascicles. These results indicate that cultured collagen fascicles change the mechanical properties and structure in response to static tensile stress. In addition, their mechanical properties and structure are maintained at control level if the static stress of 50 percent of in-vivo peak stress is applied.

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35

REASENBERG, P. A., and R. W. SIMPSON. "Response of Regional Seismicity to the Static Stress Change Produced by the Loma Prieta Earthquake." Science 255, no. 5052 (March 27, 1992): 1687–90. http://dx.doi.org/10.1126/science.255.5052.1687.

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36

Gahalaut, V. K., Kalpna, and P. S. Raju. "Rupture mechanism of the 1993 Killari earthquake, India: constraints from aftershocks and static stress change." Tectonophysics 369, no. 1-2 (July 2003): 71–78. http://dx.doi.org/10.1016/s0040-1951(03)00135-5.

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37

Qiu, Zhi Dong, and De Min Wei. "The Effects of the No-Load Factors on Static Response of the Gravity Dam." Advanced Materials Research 163-167 (December 2010): 1582–85. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.1582.

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By using finite element method, analysis the static response of internal force and displacement of gravity dam under water and no-load factors. The change of the stiffness ratio and the difference of dam and foundation stiffness at the dam heel and toe are considered. The stress in the key parts of the dam and the maximal displacement on the dam top are obtained. It is found that the change of foundation stiffness affects the stress of the dam, and the displacement decreases with the increasing of the foundation stiffness. Some computational results and conclusions are the theoretical basis for the optimization design of the gravity dam.

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38

Hiramatsu, Yoshihiro, Nobuhiko Hayashi, Muneyoshi Furumoto, and Hiroshi Katao. "Temporal changes in codaQ−1andbvalue due to the static stress change associated with the 1995 Hyogo-ken Nanbu earthquake." Journal of Geophysical Research: Solid Earth 105, B3 (March 10, 2000): 6141–51. http://dx.doi.org/10.1029/1999jb900432.

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39

Li, Siqi, Shenglei Tian, Wei Li, Xin Ling, Marcin Kapitaniak, and Vahid Vaziri. "Numerical Study on the Elastic Deformation and the Stress Field of Brittle Rocks under Harmonic Dynamic Load." Energies 13, no. 4 (February 15, 2020): 851. http://dx.doi.org/10.3390/en13040851.

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In order to study the deformation displacement and the stress field of brittle rocks under harmonic dynamic loading, a series of systematic numerical simulations are conducted in this paper. A 3D uniaxial compression simulation is carried out to calibrate and determine the property parameters of sandstone and a model of the cylindrical indenter intruding the rock is proposed to analyze the process of elastic deformation. Four main parameters are taken into account, namely the position on the rock, the frequency and the amplitude of dynamic load, the type of indenter and the loading conditions (static and static-dynamic). Based on the analysis undertaken, it can be concluded that both of the deformation displacement and stress field of the rock change in a harmonic manner under the static-dynamic loads. The frequency and the amplitude of harmonic dynamic load determine the period and the magnitude of the rock response, respectively. In addition, the existence of harmonic dynamic load can aggravate the fatigue damage of the rock and allow a reduction in static load. Our investigations confirm that the static-dynamic loads are more conducive to rock fracture than static load.

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40

Bate, Pete S., Ian Brough, and S. Morse. "Static Recovery and the Orthogonal Strain Path Change Effect in IF Steel." Materials Science Forum 550 (July 2007): 141–48. http://dx.doi.org/10.4028/www.scientific.net/msf.550.141.

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Tensile tests have been carried out in the rolling and transverse directions of 'interstitialfree' (IF) steel cold rolled to a strain of εh= -0.18. Tests in the transverse direction showed the characteristic features of the orthogonal strain path change effect, with an initially increased flow stress- compared to tests in the rolling direction- followed by a transient regime of very low strain hardening. Tests were also carried out following recovery annealing of the prestrained sheet at 500°C and 600°C. Static recovery had a marked effect on the strain-induced anisotropy, but this was not eliminated even when the cell structure generated by prestraining haD condensed to one consisting of low-angle boundaries. This supports the view that the length scale, with respect to active slip systems, between boundary obstacles is a significant factor in the orthogonal path change effect.

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41

Day, Steven M., Guang Yu, and David J. Wald. "Dynamic stress changes during earthquake rupture." Bulletin of the Seismological Society of America 88, no. 2 (April 1, 1998): 512–22. http://dx.doi.org/10.1785/bssa0880020512.

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Abstract We assess two competing dynamic interpretations that have been proposed for the short slip durations characteristic of kinematic earthquake models derived by inversion of earthquake waveform and geodetic data. The first interpretation would require a fault constitutive relationship in which rapid dynamic restrengthening of the fault surface occurs after passage of the rupture front, a hypothesized mechanical behavior that has been referred to as “self-healing.” The second interpretation would require sufficient spatial heterogeneity of stress drop to permit rapid equilibration of elastic stresses with the residual dynamic friction level, a condition we refer to as “geometrical constraint.” These interpretations imply contrasting predictions for the time dependence of the fault-plane shear stresses. We compare these predictions with dynamic shear stress changes for the 1992 Landers (M 7.3), 1994 Northridge (M 6.7), and 1995 Kobe (M 6.9) earthquakes. Stress changes are computed from kinematic slip models of these earthquakes, using a finite-difference method. For each event, static stress drop is highly variable spatially, with high stress-drop patches embedded in a background of low, and largely negative, stress drop. The time histories of stress change show predominantly monotonic stress change after passage of the rupture front, settling to a residual level, without significant evidence for dynamic restrengthening. The stress change at the rupture front is usually gradual rather than abrupt, probably reflecting the limited resolution inherent in the underlying kinematic inversions. On the basis of this analysis, as well as recent similar results obtained independently for the Kobe and Morgan Hill earthquakes, we conclude that, at the present time, the self-healing hypothesis is unnecessary to explain earthquake kinematics.

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42

Yuan, Si Cong, Xin Guo, Xiao Yu Wang, and Xi Yong Pei. "Finite Element Analysis Based on ANSYS of Bolt of Roof Bolter." Advanced Materials Research 926-930 (May 2014): 3042–45. http://dx.doi.org/10.4028/www.scientific.net/amr.926-930.3042.

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The three-dimensional solid models of five different length and shaft diameter anchor of bolt were constructed based on ANSYS software, and making static analysis and modal analysis on it to obtain the stress nephogram and natural frequency of bolt. Research on the stress condition of bolt in static analysis. In modal analysis, researching on the effect regular of the change of length and shaft diameter size on the bolt transverse vibration, the longitudinal and torsional vibration of three natural modes of different frequency, providing a reference for the structure design and reasonable choice of bolt type for corresponding condition.

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Zhou, Shenghao, and Shuogui Wang. "Study on the influence of layout angle on static stiffness and longitudinal grip of tread blocks." Journal of Physics: Conference Series 2419, no. 1 (January 1, 2023): 012037. http://dx.doi.org/10.1088/1742-6596/2419/1/012037.

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Abstract The static stiffness and longitudinal grip of the tread block are important parameters of the tire, affecting the performance of the tire, such as braking, steering, noise, and side slip properties. In order to study the influence of the layout angle of the tread block on the static stiffness and longitudinal grip of the tread block, a theoretical model of the change of the static stiffness of the tread block with the layout angle is introduced, which is considered the effect of the compression on the deformation under sliding conditions. A finite element model of the static stiffness of the tread block changing with the layout angle is established in ABAQUS, and the conclusions obtained are in good agreement with the theoretical model. On this basis, the changes in the longitudinal grip of the tread block under different layout angles are explored, and the longitudinal grip of the tread block is increased and then decreased with the increase of the layout angle, and the increase rate before reaching the peak is less than the decrease rate after reaching the peak. Comparing and analyzing the shear stress nephogram of the load-bearing slip tread block under different layout angles, it is found that when the layout angle changes, the shear stress of the tread block will be redistributed according to certain characteristics, thus affecting the longitudinal grip of the tread block.

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Xu, Yue, and Jun Wen Qiu. "Research on Influence of Contact Stress on the Hinge Moment Balance Measures." Applied Mechanics and Materials 148-149 (December 2011): 833–36. http://dx.doi.org/10.4028/www.scientific.net/amm.148-149.833.

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This paper using the method of combining balance static calibration with finite element analysis research the change and distribution law, and analyze the influence of the law on primary coefficient of hinge moment balance measurement, in conditions of different fixed-end geometry size and different preloaded force of fastening bolt.

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Wu, Qing, Ya Chen Zhang, Xue Jun Liu, and Bao An Han. "Numerical Simulation of Fluid Flow in a New High Efficient Mixer." Applied Mechanics and Materials 251 (December 2012): 226–30. http://dx.doi.org/10.4028/www.scientific.net/amm.251.226.

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In order to determine proper structural parameters of the new high efficient mixer created by the author, the CFD software is applied to simulate numerically three dimensional incompressible turbulent fields for three static mixing units and the mixing unit with rotating impellor. The static mixing units include three kinds of spiral blades that are single-blade style, three-blade style and four-blade style. Geometric models are built by Pro/ENGINEER and exported to Fluent. The time-mean Reynolds equations and standard turbulent model are applied, and the post-processing software is used to analyze the computational results, and velocity contours and stress contours of mixing fluids in the static mixer will be obtained. The computational results indicate that the direction of outlet velocity of three-blade fluid flow turns more dramatically in comparison with that of single-blade and four-blade fluid flow, and the shearing stress is more remarkable. Because the internal stress of three-blade fluid changes more, the mixing action among fluids is more intensified. All these show three-blade spiral blades have the best mixing effects for local fluids. The rotating impellor mounted between blades can change fluid flow direction and improve the mixing effect for local fluids, which is moved by fluid flow with some velocity.

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46

Nauman, E. A., R. L. Satcher, T. M. Keaveny, B. P. Halloran, and D. D. Bikle. "Osteoblasts respond to pulsatile fluid flow with short-term increases in PGE2 but no change in mineralization." Journal of Applied Physiology 90, no. 5 (May 1, 2001): 1849–54. http://dx.doi.org/10.1152/jappl.2001.90.5.1849.

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Although there is no consensus as to the precise nature of the mechanostimulatory signals imparted to the bone cells during remodeling, it has been postulated that deformation-induced fluid flow plays a role in the mechanotransduction pathway. In vitro, osteoblasts respond to fluid shear stress with an increase in PGE2production; however, the long-term effects of fluid shear stress on cell proliferation and differentiation have not been examined. The goal of this study was to apply continuous pulsatile fluid shear stresses to osteoblasts and determine whether the initial production of PGE2 is associated with long-term biochemical changes. The acute response of bone cells to a pulsatile fluid shear stress (0.6 ± 0.5 Pa, 3.0 Hz) was characterized by a transient fourfold increase in PGE2 production. After 7 days of static culture (0 dyn/cm2) or low (0.06 ± 0.05 Pa, 0.3 Hz) or high (0.6 ± 0.5 Pa, 3.0 Hz) levels of pulsatile fluid shear stress, the bone cells responded with an 83% average increase in cell number, but no statistical difference ( P > 0.53) between the groups was observed. Alkaline phosphatase activity per cell decreased in the static cultures but not in the low- or high-flow groups. Mineralization was also unaffected by the different levels of applied shear stress. Our results indicate that short-term changes in PGE2 levels caused by pulsatile fluid flow are not associated with long-term changes in proliferation or mineralization of bone cells.

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Wang, Fei, Liang Zhao, Yan Ling Zhang, and Da Lei Jing. "Effect of Adsorption Stress-Induced Change in Neutral Layer Position on Static Behavior of Microcantilever Gas Sensor." Key Engineering Materials 562-565 (July 2013): 268–75. http://dx.doi.org/10.4028/www.scientific.net/kem.562-565.268.

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The static bending model of microcantilever with monolayer molecules has been established based on energy method, in which the change in neutral layer position caused by adsorption-induced stress is introduced. On this basis, we have analyzed the relationship between the bending curvature radius of a microcantilever with its thickness, Young’s modulus and molecule-molecule distance of adsorbed molecules when it is adsorbed with monolayer water molecules. Additionally, we have investigated the effect of change in neutral layer position on the static behavior of microcantilever sensors. The results show that 1)the bending curvature radius of microcantilever is the linear, quadratic and eight approximation function of its Young’s modulus, thickness and distance of adsorbed molecules, respectively; 2)the predicted error of bending curvature radius caused by the change in neutral layer position slightly increases with decreasing Young’s modulus and thickness, whereas the effect of distance between adsorbed molecules on the error is significant; 3)the change in neutral layer position can cause a significant effect on the sensitivity and surface strain of the microcantilever

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48

Habtay Gebremicheal, Gedion, Jin Chen, Muhammed Farooq Zaman, and Xiao Ping Pang. "Design and Finite Element Analysis of a Hydraulic Excavator Boom." Advanced Materials Research 538-541 (June 2012): 568–71. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.568.

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In today’s world of growing competition, all industries are trying their best to give the components of high quality with minimum expenditure. So in present work a new semi-elliptical boom has been selected to replace the conventional boom, which is usually made of rectangular. In particular, the study wants to substitute the rectangular section for Semi-elliptical section. This change lightens the weight of the boom. For this purpose, boom with semi-elliptical cross-section has been modeled using cad software pro/E wildfire 4.0. Using VB program automatic calculation module (UPAS), the static force at different working condition of the boom calculated. Then Finite element analysis has been done to determine the static stress at a given load condition using software ANSYS 12. The result shows that total weight is reduced by 5%. The value of maximum stress and displacement is 115.663MPa and 12.885 mm respectively. Thus the structure is capable of withstanding the maximum stress. The structure is failsafe. In this paper only static stress analysis is done.

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Wang, Han-Lin, Ren-Peng Chen, Wei Cheng, Shuai Qi, and Yu-Jun Cui. "Full-scale model study on variations of soil stress in geosynthetic-reinforced pile-supported track bed with water level change and cyclic loading." Canadian Geotechnical Journal 56, no. 1 (January 2019): 60–68. http://dx.doi.org/10.1139/cgj-2017-0689.

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This study presents a full-scale model investigation on variations of soil stress in a geosynthetic-reinforced pile-supported track bed at various water levels and loading cycles, with four testing procedures: water level rising, cyclic loading at high water level, water level lowering, and cyclic loading at low water level. The soil arching effect was revealed, characterized by higher stress above the pile cap. With the water level rising and loading cycles increasing at high water level, this effect becomes more pronounced, until a peak value of dynamic stress concentration ratio is reached. The stable state of soil arching is obtained earlier near the crown of soil arching, but this arching effect develops more significantly at the foot of soil arching. With the water level lowering and loading at low water level, the soil arching effect remains steady, with slightly changed dynamic stresses in the track bed. The geogrid shows a significant impact on the load transfer mechanism for the quasi-static stress: the quasi-static pile-cap stress presents higher values below the geogrid, whereas the opposite trend is observed for the water-bag (subsoil) area. Nevertheless, this mechanism is not obvious with respect to the dynamic stress, with the values showing no distinct difference above and below the geogrid.

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Noerpamoengkas, Ardi, Miftahul Ulum, and Ahmad Yusuf Ismail. "Orientation Effect on Statics and Natural Frequency of Cantilever Beam." Jurnal Mekanova: Mekanikal, Inovasi dan Teknologi 6, no. 1 (June 4, 2020): 12. http://dx.doi.org/10.35308/jmkn.v6i1.2210.

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Statics and frequency analyzes are important because the structure can support the static and dynamic loads. Most studies about the statics and frequency are not included the gravity load. The previous studies of gravity effect to the cantilever beam included the hanging, horizontal, and inverted positions. The gravity load direction is applied referred to the longitudinal and lateral beam directions in this study. The closer to the inverted position the smaller the natural frequency. The highest values of the maximum displacement and the maximum Von-Mises stress are happened if longitudinal position is horizontal and lateral orientation angle is 0°. The change of lateral orientation angle does not influence the natural frequency in this condition. Keywords—Cantilever beam, gravity load, natural frequency, orientation angle, statics

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Journal articles on the topic 'Static stress change'

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