Numerical study on shear and normal stress variation of RC wall with L shaped section

2016 ◽  
pp. 497-500
Author(s):  
A Ahmed-Chaouch
Keyword(s):  
Normal Stress ◽  
Numerical Study ◽  
Stress Variation ◽  
Shaped Section

scholarly journals Numerical Study on Shear Stress Variation of RC Wall with L Shaped Section

2015 ◽  
Vol 59 (1) ◽  
pp. 15-25 ◽  
Author(s):  
Ali Ahmed Chaouch ◽  
Ramdane Boutemeur ◽  
Hakim Bechtoula ◽  
Abderrahim Bali
Keyword(s):  
Shear Stress ◽  
Numerical Study ◽  
Stress Variation ◽  
Shaped Section

Quantifying the influence of non-hydrostatic stress on polymorph equilibria

2021 ◽  
Author(s):  
Benjamin Hess ◽  
Jay Ague
Keyword(s):  
High Pressure ◽  
Normal Stress ◽  
Chemical Potential ◽  
Hydrostatic Stress ◽  
Low Pressure ◽  
Surprising Result ◽  
Metamorphic Petrology ◽  
Equilibrium Thermodynamics ◽  
Stress Variation ◽  
Mineral Assemblages

<p>Thermodynamic modeling in active tectonic settings typically makes the assumption that stress is equal in all directions. This allows for the application of classical equilibrium thermodynamics. In contrast, geodynamic modeling indicates that differential, or non-hydrostatic, stresses are widespread. Non-hydrostatic equilibrium thermodynamics have been developed by past workers [1], but their application to geological systems has generated controversy in recent years [2-5]. Therefore, we seek to clarify how stress influences the chemical potential of non-hydrostatically stressed elastic solids. To quantify this, we consider the effects of stress variation on the equilibrium between the single-component polymorph pairs of kyanite/sillimanite, quartz/coesite, calcite/aragonite, and diamond/graphite.</p><p>The stress on each interface of a solid can be decomposed into components normal to the interface and parallel to the interface. In our work, we determine the shift in the temperature of equilibrium on fixed interfaces between polymorph pairs as a function of both interface-normal and interface-parallel stress variation. We find that the influence of normal stress variation on the equilibrium temperature of polymorphs is approximately two orders of magnitude greater than interface-parallel stress variation. Thus, at a fixed temperature, normal stress determines the chemical potential of a given interface to first order. Consequently, high-pressure polymorphs will preferentially form normal to the maximum stress, while low-pressure polymorphs, normal to the minimum stress.</p><p>Nonetheless, interface-parallel stress variations can meaningfully affect the stability of phases that are at or near equilibrium. We demonstrate the surprising result that for a given polymorph pair, a decrease in interface-parallel stresses can make a high-pressure polymorph more stable relative to a low-pressure polymorph on the given interface.</p><p>The effects of non-hydrostatic stress on mineral assemblages are most likely to be seen in dry systems. Many reactions in metamorphic systems are fluid-mediated, and fluids cannot sustain non-hydrostatic stress. Consequently, in systems with interconnected, fluid-filled porosity, mineral assemblages will tend to form at a pressure approximately equal to the fluid pressure. In contrast, in dry systems all reactions occur directly between solids which can sustain non-hydrostatic stress. This facilitates the application of non-hydrostatic thermodynamics. Consequently, dry rocks containing polymorphs such as such as quartzites, marbles, and peridotites represent ideal lithologies for the testing and application of these concepts. By influencing the chemical potential of solid interfaces, non-hydrostatic stress alters the thermodynamic driving force and subsequent kinetics of polymorphic reactions. This likely results in preferential orientations of polymorphs which could influence seismic anisotropy and potentially generate seismicity.</p><p>[1] Larché, F., & Cahn, J. W. (1985). Acta Metallurgica, 33(3), 331-357. https://doi.org/10.1016/0001-6160(85)90077-X</p><p>[2] Hobbs, B. E., & Ord, A. (2016). Earth-Science Reviews, 163, 190-233. https://doi.org/10.1016/j.earscirev.2016.08.013</p><p>[3] Powell, R., Evans, K. A., Green, E. C. R., & White, R. W. (2018). Journal of Metamorphic Petrology, 36(4), 419-438. https://doi.org/10.1111/jmg.12298</p><p>[4] Tajčmanová, L., Podladchikov, Y., Powell, R., Moulas, E., Vrijmoed, J. C., & Connolly, J. A. D. (2014). Journal of Metamorphic Petrology, 32(2), 195-207. https://doi.org/10.1111/jmg.12066</p><p>[5] Wheeler, J. (2018). Journal of Metamorphic Petrology, 36(4), 439-461. https://doi.org/10.1111/jmg.12299</p>

Numerical study of flow fields in an airway closure model

2011 ◽  
Vol 677 ◽  
pp. 483-502 ◽  
Author(s):  
C.-F. TAI ◽  
S. BIAN ◽  
D. HALPERN ◽  
Y. ZHENG ◽  
M. FILOCHE ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Normal Stress ◽  
Numerical Study ◽  
Stress Gradient ◽  
Fluid Motion ◽  
Flow Fields ◽  
Airway Epithelial Cells ◽  
Airway Epithelial ◽  
Wall Shear

The liquid lining in small human airways can become unstable and form liquid plugs that close off the airways. Direct numerical simulations are carried out on an airway model to study this airway instability and the flow-induced stresses on the airway walls. The equations governing the fluid motion and the interfacial boundary conditions are solved using the finite-volume method coupled with the sharp interface method for the free surface. The dynamics of the closure process is simulated for a viscous Newtonian film with constant surface tension and a passive core gas phase. In addition, a special case is examined that considers the core dynamics so that comparisons can be made with the experiments of Bian et al. (J. Fluid Mech., vol. 647, 2010, p. 391). The computed flow fields and stress distributions are consistent with the experimental findings. Within the short time span of the closure process, there are large fluctuations in the wall shear stress. Furthermore, dramatic velocity changes in the film during closure indicate a steep normal stress gradient on the airway wall. The computational results show that the wall shear stress, normal stress and their gradients during closure can be high enough to injure airway epithelial cells.

The Stress Variation and Mechanism of Bearing Capacity Increment in Reinforced Foundation

2011 ◽  
Vol 71-78 ◽  
pp. 3769-3774
Author(s):  
Peng Ying Yi
Keyword(s):  
Numerical Simulation ◽  
Stress State ◽  
Normal Stress ◽  
Yield Criterion ◽  
Vertical Direction ◽  
Analysis Method ◽  
Stress Variation ◽  
Geometry Analysis ◽  
Strength Increment ◽  
Extreme State

For study the influence caused by geobelt and the mechanism of the strength increment in the reinforced foundation, the author analyzed stress state in each zone with reinforced and unreinforced, combined with the Mohr-Coulomb yield criterion, found the stress variation relationship between and in both foundations, which are found by the stress analysis method and geometry analysis method under the extreme state condition. The extreme normal stress incremental of vertical direction was solved in reinforced foundation. The essence of strength increment in reinforced foundation is revealed. The reliability of theoretical analysis was proved by numerical simulation. The conclusions show that increases in the active extreme equilibrium zone I and the passive extreme equilibrium zone Ⅲ, increases upper geobelt and decreases under geobelt in the transition zone ; the normal stress of each zone have changed correspondingly, the incremental variation of in I zone and the in Ⅲ zone has pseudo-cohesion.

Numerical Study of Cruciform Specimens for Biaxial Tensile Tests

2016 ◽  
Author(s):  
Luis F. Puente Medellín ◽  
Antonio Balvantin ◽  
J. A. Diosdado-De la Peña
Keyword(s):  
Shear Stress ◽  
Stress Distribution ◽  
Normal Stress ◽  
Sheet Metal ◽  
Numerical Study ◽  
Tensile Tests ◽  
Thickness Reduction ◽  
Shear Stresses ◽  
Normal Stress Distribution ◽  
Biaxial Tensile

This paper presents a numerical study of different geometries of cruciform specimens for biaxial tensile tests. The aim of these specimens is to be used on fixtures for biaxial tests mounted in universal testing machines. For the study, a model of isotropic material for steel sheet metal specimens was considered. Thus, only the mechanical properties of the sheet metal in the rolling direction were considered in the simulations. In this numerical analysis, the normal stress distribution and the consequent shear stress were studied. Additionally, the effect of the inclusion of multiple slots as well as a thickness reduction on the normal and shear stresses were assessed. Hence, a specimen in which a uniform normal stress distribution with zero shear stress, is necessary. The results of the analysis show that a specimen with features, multiple slots and a thickness reduction in the central area, provides a better performance in the simulations than dismissing any of these characteristics. Finally, a specimen model suitable for the mentioned test is proposed according to the obtained numerical results and the feasibility of manufacture of the experimental sample-test.

Numerical Study on Normal Stress Distributions in a Single-Lap Adhesive Joint

2014 ◽  
Vol 893 ◽  
pp. 685-689
Author(s):  
Xiao Cong He ◽  
Yu Qi Wang
Keyword(s):  
Finite Element ◽  
Normal Stress ◽  
Adhesive Joint ◽  
Numerical Study ◽  
High Stress ◽  
Element Analysis ◽  
Normal Stress Distribution ◽  
Left Hand ◽  
Accurate Indication ◽  
Hand Region

Adhesively bonding is becoming a widespread candidate technique for joining light-weight structural components. This paper investigates normal stress distribution in a single-lap adhesive joint using finite element method. Five layers of solid elements were used across the adhesive for obtaining an accurate indication of the variation of normal stress. All the numerical results obtained from the finite element analysis show that the spatial distribution of normal stress are similar for different interfaces. It can also be seen from the results that the left hand region is subjected to very high stress.

A numerical study of the effect of fibre stiffness on the rheology of sheared flexible fibre suspensions

2010 ◽  
Vol 662 ◽  
pp. 123-133 ◽  
Author(s):  
JINGSHU WU ◽  
CYRUS K. AIDUN
Keyword(s):  
Normal Stress ◽  
Numerical Study ◽  
Relative Viscosity ◽  
Normal Stress Difference ◽  
Simple Shear Flow ◽  
Strong Impact ◽  
Stress Difference ◽  
Fibre Suspensions ◽  
Particle Level ◽  
Boltzmann Method

A recently developed particle-level numerical method is used to simulate flexible fibre suspensions in Newtonian simple shear flow. In this method, the flow is computed on a fixed regular ‘lattice’ using the lattice Boltzmann method, where each solid particle, or fibre in this case, is mapped onto a Lagrangian frame moving continuously through the domain. The motion and orientation of the fibre are obtained from Newtonian dynamics equations. The effect of fibre stiffness on the rheology of flexible fibre suspensions is investigated and a relation for the relative viscosity is obtained. We show that fibre stiffness (bending ratio, BR) has a strong impact on rheology in the range BR < 3. The relative viscosity increases significantly as BR decreases. These results show that the primary normal stress difference has a minimum value at BR ~ 1. The primary normal stress difference for slightly deformable fibres reaches a minimum and increases significantly as BR decreases below one. The results are explained based on Batchelor's relation for non-Brownian suspensions.

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