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Showing papers on "Shear stress published in 2023"


Journal ArticleDOI
TL;DR: In this paper , the theoretical and numerical analyses of the shear stress distribution in the Shear band were investigated. But the analytical model and results could provide a fundamental basis for stability analysis in geotechnical engineering, and the implication for underground engineering analysis was discussed with a case study of strain rockburst in hard rock.
Abstract: Shear stress concentrations may promote damage and failure processes. Quantities of studies have focused on the direct shear loading test, while the analytical model has not yet been studied in depth. Aiming to fill the knowledge gap, the theoretical and numerical analyses of the shear stress distribution in the shear band were investigated. In order to reflect the variation in the stress state, the differential element method was first used. The shear stress distribution equation was derived from the stress equilibrium, geometric and physical equations. The shear stress distribution was plotted, using the proposed equation. After that, the ratio of yield strength to crack initiation strength was calculated. The analytical model was analyzed with FDEM simulation, and the results were compared with those obtained from the laboratory tests. Using the elastoplastic theory, the damage evolution and process in rock were characterized from laboratory scale. The implication for underground engineering analysis was finally discussed with a case study of strain rockburst in hard rock. The analytical model and results could provide a fundamental basis for stability analysis in geotechnical engineering.

9 citations


Journal ArticleDOI
TL;DR: In this article , the deformation behavior of remolded loess specimens using a hollow cylinder apparatus was investigated, where the direction of the plastic strain increment was not coaxial with direction of principal stress change simultaneously.
Abstract: Undrained torsional shear tests were carried out on remolded loess specimens using a hollow cylinder apparatus to investigate the deformation behavior and noncoaxiality (where the direction of the plastic strain increment is not coaxial with the direction of the principal stress) of remodeled loess when the magnitude and direction of the principal stress change simultaneously. It can be found that the deformation behavior of tested samples is significantly influenced by the intermediate principal stress coefficient and the rotation range of the principal stress. The influences of elastic strain, rotation range of principal stress, intermediate principal stress coefficient, and cycle period on the noncoaxiality were also studied. Analysis of the test results demonstrate obvious noncoaxiality of the remolded loess. The noncoaxiality shows segmentation characteristics. The noncoaxiality will be overestimated if the elastic strain is considered and is negative when the principal stress rotates in the reverse direction. Reversal of the principal stress leads to abrupt changes in noncoaxiality. However, the noncoaxiality is similar in the process of forward rotation and reverse rotation of the principal stress. With the same cycle period, the noncoaxiality angle decreases with an increase in intermediate principal stress coefficient, but the effect of intermediate principal stress coefficient decreases with an increase in the cycle period. Increases in the cycle period increase the noncoaxiality of the remolded loess, while the influence of the rotation range of the principal stress on the noncoaxiality is not significant.

9 citations


Journal ArticleDOI
TL;DR: In this article , the effects of Soret and Dufour on MHD nanofluid flow through a composite stenosed artery having temperature-dependent viscosity were investigated.
Abstract: This study deals with the effects of Soret and Dufour on MHD nanofluid flow through a composite stenosed artery having temperature-dependent viscosity. To determine the radiation effect in the energy equation, the Rosseland approximation has been considered in this study. The Reynolds viscosity model has been considered to describe the influence of temperature dependent viscosity. The governing equations of the model are solved numerically by applying “Finite Difference Method”. The effects of the above-mentioned parameters on the velocity, temperature and concentration along the radial axis have been studied and are physically interpreted for medical applications. Shear stress, heat transfer and mass transfer effects have been examined. The heat and mass transfer effects are studied using the Nusselt number and Sherwood number, respectively. Shear stress, Sherwood number and Nusselt number are analyzed with the help of graphs for different physical parameters along with the height of stenosis. Temperature increases with the Soret number as thermophoretic diffusion increases due to temperature gradient and decreases with the Dufour number as concentration gradient causes a decrease in energy flux. In this paper, we studied the CuNPs with blood as a base fluid under an external magnetic field. CuNPs are of great interest for many reasons, including low cost and easy availability and their similar properties to those of noble metals like silver, gold, etc. Recently, biological applications of CuNPs have been considered for several usages, such as drug delivery, antibacterial, antifungal, antiviral, anticancer, and novel therapeutic agents for combating other diseases. Enhancement in the copper nanoparticle volume fraction resulted in an increase in the thermal conductivity and dissipation of heat throughout the stenosed artery resulted in a decline of the temperature profile. This study contributes to the understanding of the nonsurgical treatment of stenosis and other anomalies, as well as the minimization of post-operative complications. Further, these studies may be helpful in the biomedical field such as magnetic resonance angiography (MRA) to take the image of an artery to locate the abnormalities in the artery.

6 citations


Journal ArticleDOI
TL;DR: In this paper , the relationship between functions of vascular ECs and different forms of fluid shear stress in AS, and also aim to provide new solutions for potential atherosclerotic therapies targeting intracellular mechanical transductions.

6 citations


Journal ArticleDOI
TL;DR: In this article , a review of WSS-related hemodynamic parameters for abdominal aortic aneurysm (AAA) is presented, focusing on how these represent different characteristics of disturbed hemodynamics.

5 citations


Journal ArticleDOI
TL;DR: In this paper , the application of the bidirectional direct simple shear (BDSS) apparatus is scrutinized so that not only are the shear and normal stress components considered, but the expected increase in the effective horizontal stress is subsequently assigned as well.

5 citations


Journal ArticleDOI
TL;DR: In this paper , the local lubrication mechanisms of textures in journal bearings were analyzed from microflow perspective, while considering the interactions between textures and the film formation in the whole bearing, and the results showed that placing textures downstream of the high-pressure region leads to a reduced friction force, with a less severe loss of load-carrying capacity.
Abstract: Adequately designed and positioned surface textures are recognized as a promising way to increase load-carrying capacity and reduce frictional losses of journal bearings. The aim of this work is to analyze the local lubrication mechanisms of textures in journal bearings from microflow perspective, while considering the interactions between textures and the film formation in the whole bearing. For this purpose, hydrodynamic lubrication models of textured journal bearings are built. The results show that placing textures downstream of the high-pressure region leads to a reduced friction force, with a less severe loss of load-carrying capacity. The effects of textures on the load-carrying capacity include the positive micro-hydrodynamic pressure effect and the negative effect caused by the discontinuity of the high-pressure region. The micro-hydrodynamic pressure of textures can be generated on one hand by limiting pressure drop (cavitation) in the divergent gap and on the other hand by the inertia effect. For the friction, the vortex inside textures affects the friction force by influencing the maximum shear stress at the minimum oil film. In turn the vortex is influenced by the bearing lubrication film. The research provides the fundamental reference and theoretical basis for the design and optimization of textured journal bearings.

5 citations


Journal ArticleDOI
TL;DR: Using microfluidics and single-cell imaging, the interplay of physical shear rate and chemical stress trigger a transcriptional response in the human pathogen Pseudomonas aeruginosa as discussed by the authors .
Abstract: Cells regularly experience fluid flow in natural systems. However, most experimental systems rely on batch cell culture and fail to consider the effect of flow-driven dynamics on cell physiology. Using microfluidics and single-cell imaging, we discover that the interplay of physical shear rate (a measure of fluid flow) and chemical stress trigger a transcriptional response in the human pathogen Pseudomonas aeruginosa. In batch cell culture, cells protect themselves by quickly scavenging the ubiquitous chemical stressor hydrogen peroxide (H2O2) from the media. In microfluidic conditions, we observe that cell scavenging generates spatial gradients of H2O2. High shear rates replenish H2O2, abolish gradients, and generate a stress response. Combining mathematical simulations and biophysical experiments, we find that flow triggers an effect like "wind-chill" that sensitizes cells to H2O2 concentrations 100 to 1,000 times lower than traditionally studied in batch cell culture. Surprisingly, the shear rate and H2O2 concentration required to generate a transcriptional response closely match their respective values in the human bloodstream. Thus, our results explain a long-standing discrepancy between H2O2 levels in experimental and host environments. Finally, we demonstrate that the shear rate and H2O2 concentration found in the human bloodstream trigger gene expression in the blood-relevant human pathogen Staphylococcus aureus, suggesting that flow sensitizes bacteria to chemical stress in natural environments.

4 citations


Journal ArticleDOI
TL;DR: In this article , a method for constructing geometric models of the carotid bifurcation and computer simulation of endarterectomy surgery with the patches of various configurations is described.

4 citations


Journal ArticleDOI
TL;DR: In this paper , the authors evaluated the contribution of geosynthetic on the shear strength of GESC under direct shear loading conditions and found that the longitudinal tensile rupture is more critical for GESCs under shear load than the circumferential tensile contraction.
Abstract: This paper presents a numerical study to evaluate the contribution of geosynthetic on the shear strength of geosynthetic encased stone column (GESC) under direct shear loading conditions. The backfill soil was characterized using the linearly elastic-plastic Mohr-Coulomb model. The geosynthetic encasement was simulated using linearly elastic liner elements. The interaction between the geosynthetic encasement and soils on both sides was modeled through two interfaces. The three-dimensional numerical model was validated using experimental data from direct shear tests of GESC models. The shear stress-strain response and the development of longitudinal and circumferential strains of GESC during the shear process were first discussed, and then a parametric study was conducted to investigate the effects of various design parameters on the shear strength of GESC and the contribution of geosynthetic. Results indicate that the shear resistance provided by the geosynthetic encasement develops slowly, which depends on the mobilization of tensile strains. At the failure condition, the longitudinal strains are larger than the circumferential strains, which indicates that the longitudinal tensile rupture is more critical for GESC under shear loading. The vertical stress, geosynthetic encasement stiffness, stone column diameter and spacing have the most important influences on the shear strength contribution of geosynthetic encasement.

3 citations


Journal ArticleDOI
14 Apr 2023-Water
TL;DR: In this article , the effect of aspect ratio and the Keulegan-Carpenter (KC) number on scour depth in combined wave-current flows around rectangular piles with various aspect ratios is investigated.
Abstract: This study utilizes three-dimensional simulations to investigate scour in combined wave–current flows around rectangular piles with various aspect ratios. The simulation model solves the Reynolds-averaged Navier–Stokes (RANS) equations using the k–ω turbulence model, and couples the Exner equation to compute bed elevation changes. The model also employs the level-set approach to realistically capture the free surface, and couples a hydrodynamic module with a morphological module to simulate the scour process. The morphological module employs a modified critical bed shear stress formula on a sloping bed and a sand-slide algorithm for erosion and deposition calculations in the sediment bed. To validate the numerical model, simulations are conducted in a truncated numerical wave tank with the Dirichlet boundary condition and active wave absorption method. After validation, the numerical model is used to investigate the effect of aspect ratio and the Keulegan–Carpenter (KC) number on scour depth in a combined wave–current environment. The study finds that the normalized scour depth is highest for a rectangular pile with an aspect ratio of 2:1 and lowest for an aspect ratio of 1:2. The maximum normalized scour depth (S/D) for aspect ratios of 2:1 are 0.151, 0.218, and 0.323 for KC numbers 3.9, 5.75, and 10, respectively, whereas the minimum normalized scour depth (S/D) for aspect ratios of 1:2 are 0.132, 0.172, and 0.279. Additionally, the research demonstrates that the normalized scour depth increases with an increase in the KC number for a fixed wave–current parameter (Ucw).

Journal ArticleDOI
TL;DR: In this article , a 3D discrete element method (DEM) model of the direct shear of sand was performed using sphere particles to explore the ability of the rolling resistance linear contact model to reproduce this commonly used test considering real-size particles.
Abstract: This paper deals with the micro and macro behaviors of coarse sand inside a direct shear box during a geotechnical test. A 3D discrete element method (DEM) model of the direct shear of sand was performed using sphere particles to explore the ability of the rolling resistance linear contact model to reproduce this commonly used test considering real-size particles. The focus was on the effect of the interaction of the main contact model parameters and particle size on maximum shear stress, residual shear stress, and sand volume change. The performed model was calibrated and validated with experimental data and followed by sensitive analyses. It is shown that the stress path can be reproduced appropriately. For a high coefficient of friction, the peak shear stress and volume change during the shearing process were mainly affected by increasing the rolling resistance coefficient. However, for a low coefficient of friction, shear stress and volume change were marginally affected by the rolling resistance coefficient. As expected, varying the friction and rolling resistance coefficients was found to have less influence on the residual shear stress.


Journal ArticleDOI
03 Jan 2023-Water
TL;DR: In this paper , a conceptual model of a gradual varied flow with both convective deceleration and acceleration flow sections has been constructed in a flume to study turbulent flow structures, and the results showed that the application of the log law should be used with care to estimate shear velocity along a pool with a vegetated bed.
Abstract: Pools are often observed in gravel-bed rivers, together with the presence of vegetation patches. In the present study, a conceptual model of a gradual varied flow with both convective deceleration and acceleration flow sections has been constructed in a flume to study turbulent flow structures. Vegetation patches with extended canopies were planted in the pool sections in order to increase the thickness of the boundary layer inside the inner zone. The effects of different flows (namely decelerating, uniform and accelerating flows) along an artificial pool on flow velocity, shear stress and bursting events have been investigated. In addition, due to the occurrence of secondary currents in shallow streams, the characteristics of turbulent shallow flow have been investigated along two axes that are parallel to the sidewall of the flume. The results showed that the application of the log law should be used with care to estimate shear velocity along a pool with a vegetated bed. The presence of a vegetation patch causes an increase in Reynolds shear stress, especially along the entrance section of the pool where the flow decelerates. The results of the quadrant analysis reveal that the sweep and ejection events have the most dominant influence over the vegetation patch in the pool; however, the contributions of outward and inward events increase near the bed, especially in the entrance section of the pool where the flow is decelerating. The distribution of stream-wise RMS of turbulence intensity along the pool generally presents a convex shape.

Journal ArticleDOI
TL;DR: In this paper , the chip formation mechanism can be divided into two types: crack and shear, and it is found that higher quality machined surfaces can be obtained through chip formation process by shear than by crack.

Journal ArticleDOI
TL;DR: In this paper , stent-induced deformations of the parent vessel of ICA aneurysms are fully investigated, and the authors tried to visualize blood stream and calculated hemodynamic factors inside the four ICAAneurysm after deformations.
Abstract: Abstract Application of the stent for treatment of the internal carotid artery (ICA) aneurysms has been extensively increased in recent decades. In the present work, stent-induced deformations of the parent vessel of ICA aneurysms are fully investigated. This study tries to visualize blood stream and calculated hemodynamic factors inside the four ICA aneurysms after deformations of parent vessel. For the simulation of the non-Newtonian blood stream, computational fluid dynamic is applied with one-way Fluid–Solid interaction (FSI) approach. Four ICA aneurysms with different ostium sizes and neck vessel angle are selected for this investigation. Wall shear stress on wall of aneurysm is analyzed in two angles of deformation due to application of the stent. Blood flow investigation shows that the deformation of the aneurysm limited blood entrance to the sac region and this decreases the blood velocity and consequently oscillatory shear index (OSI) on the sac wall. It is also observed that the stent-induced deformation is more effective on those cases with extraordinary OSI values on aneurysm wall.

Journal ArticleDOI
TL;DR: In this paper , the shear sliding tests under unloading normal stress were conducted regarding various initial normal stresses (1 −7 MPa) and numbers of shearing cycles (1 -5).
Abstract: Through high-precision engraving, self-affine sandstone joint surfaces with various joint roughness coefficients (JRC = 3.21–12.16) were replicated and the shear sliding tests under unloading normal stress were conducted regarding various initial normal stresses (1–7 MPa) and numbers of shearing cycles (1–5). The peak shear stress of fractures decreased with shear cycles due to progressively smooth surface morphologies, while increased with both JRC and initial normal stress and could be verified using the nonlinear Barton-Bandis failure criterion. The joint friction angle of fractures exponentially increased by 62.22%–64.87% with JRC while decreased by 22.1%–24.85% with shearing cycles. After unloading normal stress, the sliding initiation time of fractures increased with both JRC and initial normal stress due to more tortuous fracture morphologies and enhanced shearing resistance capacity. The surface resistance index (SRI) of fractures decreased by 4.35%–32.02% with increasing shearing cycles due to a more significant reduction of sliding initiation shear stress than that for sliding initiation normal stress, but increased by a factor of 0.41–1.64 with JRC. After sliding initiation, the shear displacement of fractures showed an increase in power function. By defining a sliding rate threshold of 5 × 10−5 m/s, transition from “quasi-static” to “dynamic” sliding of fractures was identified, and the increase of sliding acceleration steepened with JRC while slowed down with shearing cycles. The normal displacement experienced a slight increase before shear sliding due to deformation recovery as the unloading stress was unloaded, and then enhanced shear dilation after sliding initiation due to climbing effects of surface asperities. Dilation was positively related to the shear sliding velocity of fractures. Wear characteristics of the fracture surfaces after shearing failure were evaluated using binary calculation, indicating an increasing shear area ratio by 45.24%–91.02% with normal stress.

Journal ArticleDOI
TL;DR: In this paper , a new method for predicting the instability of joints under normal unloading was proposed based on the evolution law of normal deformation energy (Un), tangential deformation energies (Us) and total deformation Energy (U0), which can be used to predict the unloading instability of rock mass using the abrupt change of U0.
Abstract: As a composite material, the stability of rock mass is usually controlled by a joint. During the process of excavation, the normal stress of the joint decreases continuously, and then the shear strength of the joint decreases, which may eventually lead to the instability and failure of rock mass. Previous studies have mainly focused on the shear behavior of joints under constant normal stress, but have rarely considered the unloading of normal stress. In this paper, a direct shear test of joints with different roughness was carried out, in which the shear stress remained unchanged while the normal stress decreased. The strength characteristics of joints were explored, and the deformation and acoustic emission-counting characteristics of joints were analyzed by digital image correlation (DIC) techniques and acoustic emission (AE). A new method for predicting the instability of joints under normal unloading was proposed based on the evolution law of normal deformation energy (Un), tangential deformation energy (Us) and total deformation energy (U0). The results show the following: (1) The unloading amount of normal stress was enlarged for greater initial normal stress and roughness, while it decreased with an increase in initial shear stress. (2) AE events reached their maximum when the normal stress was equal to the failure normal stress, and the b-value fluctuated more frequently in stable development periods under normal unloading conditions. (3) U0 would change with the loading and unloading of stress, and this may be used to predict the unloading instability of rock mass using the abrupt change of U0.

Journal ArticleDOI
TL;DR: In this article , a fractional second-grade fluid model with ternary nano-particles (Cu, Ag, CuO) is implemented to investigate the effects of electroosmotic forces (EMHD) through an oblique stenosed aneurysmal artery.

Journal ArticleDOI
TL;DR: In this article , a set of 48 cyclic and 12 monotonic large-scale direct shear tests was performed to assess the interface properties of sand-rubber composite along a nonwoven geotextile layer.
Abstract: A set of 48 cyclic and 12 monotonic large-scale direct shear tests was performed to assess the interface properties of sand–rubber composite along a nonwoven geotextile layer. Rubber content, semiamplitude of the shear displacement, and applied normal stress all were varied to determine the cyclic, postcyclic, and monotonic interface response of the composite system under shear loading. The test results show that adding 40% granulated rubber to pure sand caused approximately 50% reduction in the maximum mobilized interface shear stress as the loading cycles progressed. The addition of granulated rubber to the sand decreased both the damping and the shear stiffness of the interface for all values of displacement amplitude and normal stress; in particular, for the energy dissipation, the observations were associated with the higher linearity of the stress–strain relationship when adding rubber, thereby reversing the typical trend of higher damping at smaller strains or displacements. In addition, an increase in the displacement amplitude value yielded a reduction in the secant shear stiffness, but contrarily increased the damping ratio of the geotextile–composite soil interface. An increasing trend of the hardening factor was observed through the initial cycles of loading for the samples containing 40% granulated rubber, which was ascribed to the increased densification capability of the sand–rubber mixture with the progression of the loading cycles; however, this response was not captured for the pure sand–geotextile interface.

Journal ArticleDOI
TL;DR: In this article , the authors analyzed the shear behavior of prismatic and tapered continuous beams with corrugated steel webs (CSWs) under different external prestressing tendon layouts.
Abstract: This paper analyzes the shear behavior of prismatic and tapered continuous beams with corrugated steel webs (CSWs) under different external prestressing tendon layouts. For girder bridges with CSWs, the existing design specifications consider only the shear force caused by the external prestressing force when calculating the shear stress of CSWs under the external prestressing tendons. However, in a tapered continuous beam with CSWs, in addition to the shear force caused by the prestressing force, the prestressing bending moment and the horizontal component of prestressing can also induce additional shear stress, which results in a redistribution of the shear stress on the section. This finding has not been reported previously. Then, the reasons for the shear behavior differences of tapered and prismatic continuous beams with CSWs under external prestressing tendons are explored. The study reveals the factors affecting the distribution of shear stress on indeterminate static beams with CSWs under external prestressing and proves that the traditional method used for predicting the shear stress on CSWs is not applicable to tapered cases. In addition, it is found that the direction of the internal forces and moments also affects the shear-bearing ratios of CSWs and concrete slabs. Consequently, a unified analytical formula is proposed for calculating the shear stresses of the CSWs induced by external prestressing, and it can be applied to both tapered and prismatic continuous beams with CSWs under external prestressing tendons.


Journal ArticleDOI
TL;DR: In this article , the axisymmetric steady flow of a couple stress fluid between two concentric cylinders with a slip effect is investigated with the help of the cell model technique.
Abstract: The axisymmetric steady flow of a couple stress fluid between two concentric cylinders with a slip effect is investigated with the help of the cell model technique. Here, the inner cylinder is rigid, and the outer cylinder is fictitious. The tangential slip, vanishing of normal velocity, and zero couple stress conditions are applied on the inner cylindrical surface. In addition, zero shear stress (Happel's model), continuity of normal velocity component, and zero couple stress conditions are used on the outer cylindrical surface. We consider two flow problems: the first is the parallel flow, and the second is the perpendicular flow to the cylinder in the cell model. Also, we have discussed the random case. For all the cases, the Kozeny constant is calculated. We described some special cases and compared them with well-known results. The effects of slip and couple stress parameters on the Kozeny constant with fixed value of couple stress viscosity parameter are presented graphically. The influence of the couple stress viscosity parameter on the Kozeny constant with fixed values of couple stress, and slip parameters for parallel flow are expressed graphically. The numerical values for the Kozeny constant for different values of fractional void volume are tabulated. We also obtained the results of the consistent couple stress theory as a special case.

Journal ArticleDOI
TL;DR: In this paper , an explicit formulation for estimating grain shear stress was developed to predict the bed load transport rate in a vegetated channel by considering the superimposition of forces.
Abstract: The prediction of bedload transport capacity in riverbed with aquatic vegetation is a pressing need for river restoration. Laboratory experiments were conducted to investigate the weak bed-load transport rates with emergent vegetation for different energy slopes and vegetation densities. Such rate was observed to increase as the energy slope increased and the vegetation density decreased. The bed shear stress calculated by subtracting the vegetation drag from the total flow driving force was unable to predict the measured bed-load transport rate. On the other side, the estimation of the grain shear stress using the Einstein partitioning method considering the form drag provided a reasonable prediction. On the basis of these results, an explicit formulation for estimating grain shear stress was developed to predict the bed-load transport rate in a vegetated channel by considering the superimposition of forces. In addition, a simple relationship between grain shear stress and total shear stress was established by the boundary layer model. It was inferred that bed-load transport rate decreases with the increase of vegetation blocking factor while the total shear stress remains constant. Comparatively, the proposed models were more accurate than literature models, improving the understanding of the bed-load transport in a vegetated flow.

Journal ArticleDOI
TL;DR: In this paper , the authors conducted triaxial shear tests driven by displacement on shale samples with prefabricated sawcut and natural fractures, and the acoustic emission (AE) technology was used to monitor the shear-slip process in real-time.

Journal ArticleDOI
TL;DR: In this article , the normal stress ratio and fiber content of carbon fiber recycled aggregate concrete were used as design parameters to examine the compressive-shear mechanical properties of a carbon fiber aggregate concrete.
Abstract: The application potential of recycled aggregate concrete has been realized with the development and utilization of waste concrete. Fibers are added to concrete made with recycled coarse aggregate to enhance its mechanical properties and broaden its application possibilities. Additionally, in practical applications, parts of structural elements are frequently under compression‐shear stress. As a result, the normal stress ratio k (k = σ/fcu, where σ is axial compressive stress, and fcu is concrete cube compressive strength), coarse aggregate replacement rate, and carbon fiber content are used as design parameters to examine the compressive‐shear mechanical properties of carbon fiber recycled aggregate concrete in this paper. The results show that the normal stress ratio and fiber content affect the whole compression‐shear process curve, shear strength, peak shear displacement, and damage evolution. A compressive shear damage model that takes into account the aggregate replacement rate, normal stress ratio, and fiber content is established. And there is good agreement between the experimental findings and the calculation model.

Journal ArticleDOI
TL;DR: In this paper , the authors investigated the hemodynamics parameters and their impact on the aneurysm rupture and concluded that the flow recirculation appears in the anterior communicating artery and the effect of the recurvability on the bulge hemodynamics wall parameters is discussed to identify the rupture zone.
Abstract: Abstract In this study, we investigate the hemodynamics parameters and their impact on the aneurysm rupture. The simulations are performed on an ideal (benchmark) and realistic model for the intracranial aneurysm that appears at the anterior communicating artery. The realistic geometry was reconstructed from patient-specific cerebral arteries. The computational fluid dynamics simulations are utilized to investigate the hemodynamic parameters such as flow recirculation, wall shear stress, and wall pressure. The boundary conditions are measured from the patient using ultrasonography. The solution of the governing equations is obtained by using the ANSYS-FLUENT 19.2 package. The CFD results indicate that the flow recirculation appears in the aneurysms zone. The effect of the flow recirculation on the bulge hemodynamics wall parameters is discussed to identify the rupture zone.

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TL;DR: In this article , the influence of rolling motion on the friction resistance of a 3 × 3 rod bundle channel under rolling motion was investigated by numerical simulation to overcome the limitation of experimental conditions and measurement methods.

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TL;DR: In this paper , a new anchor cable with a high support and large shear deformation is proposed, which consists of free, grouting, and adaptive sections, which are connected using hinge connections.

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TL;DR: Wang et al. as mentioned in this paper comprehensively review the systemic risk factors, hemodynamics and biological factors involved in the formation of atherosclerosis, and combine the application of CFD in hemodynamics, focusing on the mechanism of WSS and the complex interactions between Wss and plaque biological factors.
Abstract: Atherosclerosis (AS) is the major form of cardiovascular disease and the leading cause of morbidity and mortality in countries around the world. Atherosclerosis combines the interactions of systemic risk factors, haemodynamic factors, and biological factors, in which biomechanical and biochemical cues strongly regulate the process of atherosclerosis. The development of atherosclerosis is directly related to hemodynamic disorders and is the most important parameter in the biomechanics of atherosclerosis. The complex blood flow in arteries forms rich WSS vectorial features, including the newly proposed WSS topological skeleton to identify and classify the WSS fixed points and manifolds in complex vascular geometries. The onset of plaque usually occurs in the low WSS area, and the plaque development alters the local WSS topography. low WSS promotes atherosclerosis, while high WSS prevents atherosclerosis. Upon further progression of plaques, high WSS is associated with the formation of vulnerable plaque phenotype. Different types of shear stress can lead to focal differences in plaque composition and to spatial variations in the susceptibility to plaque rupture, atherosclerosis progression and thrombus formation. WSS can potentially gain insight into the initial lesions of AS and the vulnerable phenotype that gradually develops over time. The characteristics of WSS are studied through computational fluid dynamics (CFD) modeling. With the continuous improvement of computer performance-cost ratio, WSS as one of the effective parameters for early diagnosis of atherosclerosis has become a reality and will be worth actively promoting in clinical practice. The research on the pathogenesis of atherosclerosis based on WSS is gradually an academic consensus. This article will comprehensively review the systemic risk factors, hemodynamics and biological factors involved in the formation of atherosclerosis, and combine the application of CFD in hemodynamics, focusing on the mechanism of WSS and the complex interactions between WSS and plaque biological factors. It is expected to lay a foundation for revealing the pathophysiological mechanisms related to abnormal WSS in the progression and transformation of human atherosclerotic plaques.