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This study attempts to build on the understanding of building behavior by analyzing the base shear as well as the lateral forces, on available storey levels, in seismic zones II and III, when buildings are erected on the three soil-types. The seismic loading applied is in accordance with the varying parameters of zone, soil type, and the structure height. Varying heights in the buildings is as follows: G+3, G+6 (with storey height being 3m.) The gathered observations speak of the similarity in the impact of the loads on the structures when the soil type changes. For G+3 structures the base shear and storey shear is identical in all the soil types where as for the G+6 structures there is a variation in hard soil while it is same in other two soil type.

We explore theoretically the interplay between shear banding and edge fracture in complex fluids, by performing a detailed simulation study within two constitutive models: the Johnson-Segalman model and the Giesekus model. We consider separately parameter regimes in which the underlying constitutive curve is monotonic and non-monotonic, such that the bulk flow (in the absence of any edge effects) is respectively homogeneous and shear banded. Phase diagrams of the levels of edge disturbance and of bulk (or quasi-bulk) shear banding are mapped as a function of the surface tension of the fluid-air interface, the wetting angle where this interface meets the walls of the flow cell, and the imposed shear rate. In particular, we explore in more detail the basic result recently announced in Hemingway et al. (2018): that precursors to edge fracture can induce quasi-bulk shear banding. We also appraise analytical predictions that shear banding can induce edge fracture, Skorski and Olmsted (2011). Although a study of remarkable early insight, that study made some strong assumptions about the nature of the "base state", which we examine using direct numerical simulation. The basic prediction that shear banding can cause edge fracture remains valid, but with qualitatively modified phase boundaries., Comment: 14 pages, 6 figures

This paper numerically investigates the physical behavior of deep geological structures in the Yakutsk-Vilyui large igneous province (LIP). The geophysical data of “Craton-1980” profile was used to create the computer structures of the researched area. To analyze the inelastic deformation, the Nikolaevsky elastoplastic model was used. For investigating the geotectonic processes the strength model, which operates with cohesion and coefficient of internal friction, was adapted to the Nikolaevsky model. The depth analysis of the stress state was realized making use of the pressure and the Lode parameter. It is shown that the distribution of the Lode parameter depends on inelastic strain localization and reveals mainly the shear type of deviatoric stress. The distribution of pressure has a quasi-monotonic increasing with depth, with local disturbances caused by the shear bands in the depth layers of Earth's crust. These features are more pronounced with increasing of horizontal deformation. These results can be used by geologists to evaluate the metamorphism of rocks.

The research was performed of strength properties and failure mechanism of shale samples of layered structure under shear loading with coupled compression. The effect of angles of orientations of stratification planes Ψ and angles of shear plane Δ on ultimate shear strength of shale specimens was analyzed. The results indicate that ultimate shear strength depends on combination of values of bedding angle and angle of shear plane relative to the stratification. The empirical dependences of the cohesion on angles Ψ and Δ were obtained. Minimum and maximum values of cohesion have been defined depending on values of angles Ψ and Δ. The combinations of angles Ψ and Δ are determined that are most dangerous for shear fracture of rocks of layered structure.

Due to various architectural requirements the structures are subjected to large shear stresses and hence the study of shear performance of structural materials is essential. Push-off test is a simple test which can be performed to determine the in-plane shear strength (IPSS) of materials effectively. Geopolymer concrete is a recent construction material which is a suitable alternative cement concretes especially in precast construction due to the non-requirement of cement, the manufacture of which is energy intensive and involves the liberation of CO2 which is a known pollutant and leads to global warming. Concrete has good performance under compressive loads and fails generally due to crack propagation, bridging of these cracks can improve the load carrying capacity of the concrete, addition of fibre is one such method available where the fibres act as crack arrestors. The present experimental investigation has made an effort to understand the influence of fibres over shear strength of Geo Polymer Concrete (GPC) adopting push-off specimen. From the experimental studies it was observed that shear strength and resistance against cracking increased with increase in fibre volume and the effectiveness of GPC reinforced by fibres were higher than that of NSC specimen.Due to various architectural requirements the structures are subjected to large shear stresses and hence the study of shear performance of structural materials is essential. Push-off test is a simple test which can be performed to determine the in-plane shear strength (IPSS) of materials effectively. Geopolymer concrete is a recent construction material which is a suitable alternative cement concretes especially in precast construction due to the non-requirement of cement, the manufacture of which is energy intensive and involves the liberation of CO2 which is a known pollutant and leads to global warming. Concrete has good performance under compressive loads and fails generally due to crack propagation, bridging of these cracks can improve the load carrying capacity of the concrete, addition of fibre is one such method available where the fibres act as crack arrestors. The present experimental investigation has made an effort to understand the influence of fibres over shear strength of Geo Polymer Concre...

The molecular dynamics method is used to study the features of nucleation and development of plasticity in nanocrystalline iron under shear loading in constrained conditions. The behavior of the material under loading is divided into several stages. On each of them the mechanisms of plastic deformation are revealed, which play the main role in the development of structural rearrangements in the loaded sample. It is shown that the nucleation and slip of dislocations plays a significant role in the development of plasticity at all stages of deformation. Subsequently, along with intragranular slip, grain boundary sliding is activated. Twinning leads to the localization of plastic deformation and changes grain shapes. At a further shear, the process of grain boundary migration is activated, which results in recrystallization of the deformed sample.

Magnesium and its alloys are widely used in the aerospace, automotive and defense industries, taking advantage of its high strength to weight ratio. However, these materials show strong anisotropy with its hexagonal close packed structure and texture. The experimental investigations probing the behavior of these materials at high pressures and strain rates are limited. In this study, experiments are conducted on extruded commercially pure magnesium using pressure shear plate impact (PSPI) experiments. The strength and the behavior of the materials are measured at pressures up to 10.5 GPa and strain rates of 105 s−1. The PSPI experiments measure the materials under unique conditions, loading the material simultaneously in two directions. Experiments are conducted at two different pressures where the normal compressive stresses are aligned in one direction and the shear stresses, probing the material strength, are aligned perpendicular to the direction of the normal stress. The effect of pressure on the behavior of these materials under high pressures and strain rates are discussed. It was seen that magnesium exhibit higher strength at higher pressures due to the pressure hardening.

The article presents the results of a study of the influence of a high-temperature synthesis product deformation on the strength properties of a Ni3Al intermetallic compound synthesized under pressure. The anomalous dependence of the strength properties of the synthesized under pressure intermetallic in the temperature range of 20–1000°C is investigated It is established that high-temperature synthesis under pressure forms a gradient low-dimensional grain structure in the volume of the synthesized intermetallic. The results of the appraisal of shear strain role under conditions of axial compression of the synthesis product in the of grains structure formation obtained using numerical simulation are presented. It is established that the pattern of grain size distribution in the volume of the synthesized intermetallic depends on the features of the passage of the shear strain front in the billet at the stage of load influence.

Increased mineralization of some fluid layers in companson with that of the other layers causes the appearance of concentration-induced convection. This type of convection is most pronounced for brines of surface water bodies, salt marshes, saline rocks, etc. Nevertheless, concentration-induced convection occurs not only in natural reservoirs, but also in technical devices due to the inhomogeneous distribution of vanous impurities in hydraulic media. The characteristics of impurity distribution have a significant effect on the flow charactenstics. The paper considers a shear convective flow of a viscous incompressible fluid in a horizontal layer, which is induced by the nonuniform distribution of impurity concentration. A system of equations for concentration-induced convection is used to descnbe such flows; a solution is sought among classes of generalized solutions. As the boundary conditions, it is assumed that the no-slip condition is satisfied at the lower impermeable boundary, that the upper boundary of the layer is motionless, and that the distribution of salinity and pressure is specified on it. A solution to the descnbed boundary value problem is obtained. The attention is focused on the analysis of the properties of the flow velocity field. The conditions at which the flow reduces to a unidirectional one are denved. It is shown that none of the velocity field components can vanish inside the fluid layer, i.e. that the fluid layer cannot be divided into zones in such a way that the fluid would change the flow direction when transiting from one zone to another. © 2020 American Institute of Physics Inc.. All rights reserved.

In this study, we invert the receiver function beneath GSI seismic station to estimate the crustal structure beneath Nias Island, Sumatra. The receiver function is computed from 24 teleseismic events using a time-domain deconvolution technique and divided into three groups by observations with similar back azimuth namely GSI_NW, GSI_NE, and GSI_SE. The resulted receiver function then stacked to increase the signal-to-noise ratio. The shear wave velocity structures of the crust are obtained by inverting receiver functions using linearized-iterative inversion with A0K-135 for the initial model. The inversion result shows a thick sediment layer ranged from 1 to 3 km with velocities around 2,4 km/s near the surface. The Moho and the top of the subducting oceanic slab are observed around 22-24 km and 32 km depth respectively. The low shear wave velocity above the transition to the subducting slab is suggested as the signature of the serpentinization.

Along with the initial elastic and strength properties, the deformation and fracture process in rocks is significantly affected by their degradation during loading. In the present work, we supplement the Drucker–Prager model of the medium by the equation for cohesion degradation. Growing irreversible plastic deformation weakens the rock. Upon complete failure, the rock behaves like dry sand, which resists only compressive and shear loads. The model gives results that are in good agreement with field observations and physical modeling predictions. A possibility is shown of forming positive structures without setting additional boundary conditions of transverse compression for rocks like clays, sands, and soft sandstone.

Depending on the reasons causing changes in the density of a fluid, it is customary to distinguish between thermal convection and concentration-induced convection. The phenomenon of concentration-induced convection often accompanies the flow of a working fluid in devices working, for example, with fluid coolants. When modeling such flows, the consideration of the generalization of the Boussinesq hypothesis assuming the dependence of the fluid density on the impurity concentration and on the temperature of the fluid itself leads to the situation that the flow velocity field and the concentration field affect each other. The paper investigates the features of the shear convective flow of a viscous incompressible fluid with an admixture in the horizontal layer. The system of concentration-induced convection equations consisting of the equation of motion of a viscous fluid, the concentration change equation, and the incompressibility condition is taken as a system of defining relations. The solution is sought in the class of functions linear in two coordinates (x a n d,). As the boundary conditions, it is assumed that the no-slip condition is met at the lower impermeable boundary, that the upper boundary of the layer is immobile, and that the distribution of salinity and pressure is specified on it. A complete solution of the boundary value problem is given. The attention is focused on the analysis of the distribution of the concentration field inside the fluid layer. It is s h o w that, according to the solution of the boundary value problem for the concentration field, its homogeneous (with respect to the horizontal coordinates) component does not vamsh inside the layer. The components of the concentration field, linearly dependent on the honzontal coordinates, take a constant value everywhere inside the layer. The change in the mutual arrangement of the isolines of the concentration field at the transition from one section of the fluid layer to another is studied. Relevant findings are illustrated. © 2020 American Institute of Physics Inc.. All rights reserved.

Rheological properties are based on material science approach and are necessary to overcome the deficiency of experimental tests such as slump test. In rheological method the flow characterisation of fresh concrete is described by two parameters namely yield stress and plastic viscosity (rheological properties). These parameters provide better understanding of concrete and enhance the quality of concrete thereby designing a more economical complex structure with improved construction processes. In the present study the rheological properties of low workability of fresh concrete with targeted slump varying from 0 to 50 mm are considered. Totally 12 different mixes were used with three varied cement contents of 300, 375 and 450 kg/m3 along with varying water contents of 115,130,145 and 160 lt/m3. The absolute volume concept is the basis for designing the concrete mixes. Totally 108 trials were considered with three varied shear rates of 5, 15, 25 mm/min and three varied normal stresses of 0.15, 0.25, 0.35 MPa. The results and observations reinforce the usefulness of concrete shear box as an additional instrument to find the rheological properties by making use of Bingham model as a static test with a low shear rate.Rheological properties are based on material science approach and are necessary to overcome the deficiency of experimental tests such as slump test. In rheological method the flow characterisation of fresh concrete is described by two parameters namely yield stress and plastic viscosity (rheological properties). These parameters provide better understanding of concrete and enhance the quality of concrete thereby designing a more economical complex structure with improved construction processes. In the present study the rheological properties of low workability of fresh concrete with targeted slump varying from 0 to 50 mm are considered. Totally 12 different mixes were used with three varied cement contents of 300, 375 and 450 kg/m3 along with varying water contents of 115,130,145 and 160 lt/m3. The absolute volume concept is the basis for designing the concrete mixes. Totally 108 trials were considered with three varied shear rates of 5, 15, 25 mm/min and three varied normal stresses of 0.15, 0.25, 0.35 M...

In the framework of the molecular dynamics method, different plasticity mechanisms in a nanocrystalline bcc iron sample under shear loading were investigated. It was shown that the nucleation of plasticity occurs in grains for which the orientation of twinning planes is close to the direction of shear. First, plasticity in the sample is realized through the generation of twins and dislocations. Then, accommodation of the structure of the sample involves such grain-boundary processes as a change in the grain shape, grain boundary sliding and grain boundary migration.

This work reports the morphology and evolution of deformation relief of polycrystalline nickel. The morphological peculiarities of the relief are investigated using atomic force microscopy. The material fragmentation is shown to be presented by shear strain domains. The main structural elements of the deformation relief are the packs of shear traces and macrobands. The strain (taking into account the individual structural elements of the relief through the sample) is found to be qualitatively equal at the different scales, exhibiting the quasiperiodic behavior. The shear traces with increase in strain are found to evolve into macrobands. In turn, the strain-induced macrobands are composed of the individual shear levels and possess a quasiperiodic profile.

Jati Agung District is an area planned by the Lampung government to become a new city of the central government in Lampung. Aspects of city planning include aesthetics and safety. The geophysical study is conducted as disaster mitigation efforts to make the city have a good level of safety. The purpose of this study is to measure earthquake activities in the research areas that could be developed as data in disaster mitigation. The geophysical study was conducted by measuring the microtremor at 15 points. The microtremor signal is processed by the HVSR method to obtain information on natural frequency and amplitude. Natural frequencies and amplifications were analyzed to obtain the Peak Ground Acceleration (PGA) and Ground Shear Strain (γ) values. The results of PGA values and Ground Shear Strains indicate indications of soil fracture-prone areas. The results showed that the PGA value was 12.34638 gal to 22.18974 gal, while the Ground Shear Strain (γ) value was 53.34322x10−6 to 729.6847x10−6. The area of this study is a very safe area against the impact of earthquakes. Because the deformation in the event of an earthquake is very small, this is due to the type of rock found. In the study area, the type is rock that has large compacting properties. Also based on the geography on this research area is a region that is quite safe from tsunami waves, because in the west there are high mountains, and there are also small islands that can reduce tsunami waves from the southwest of the research location (Jati Agung Area).

The initiation of a longitudinal shear crack (mode III fracture) in homogeneous structures and weld joints of elastoplastic materials with the limiting strain is considered. To obtain critical fracture parameters, a coupled (sufficient) fracture criterion in an elastoplastic material is used. Simple relations for critical shear stresses, lengths of pre-fracture zones and critical stress intensity factor (SIF) for mode III fracture were obtained. There is a limiting transition from a sufficient fracture criterion to the necessary criterion, when the length of the prefracture zone tends to zero. Critical stresses obtained according to necessary and sufficient criteria differ significantly. In the framework of the proposed model, the critical SIF obtained by a sufficient criterion is a variable, it depends on the grain diameter, the parameters of the material strain diagram and the crack length. The rule of selection of the parameters of the proposed fracture model is indicated by two laboratory experiments: by approximating the material strain diagram with a simple shear and critical SIF. The obtained critical parameters are conservative estimates of critical stresses. These estimates should be used in the calculation of steel structures operating at temperatures below the cold brittleness.

Turbulent bubble flow applications for fluid engineering are becoming increasingly common. The horizontal movement of turbulent bubble flow in the vertical shear flow is considered to be the most important. With the goal of clarifying the mechanism of action of the turbulence on the lateral movement of an emerging bubble, a simulation model is proposed in this study to describe the motion properties of spherical bubbles in a homogeneous mixture under the influence of vertical shear forces. With the assumption that light solid particles are treated as surfactants, it may be those that cause the bubble to be contaminated. In this study, the submerged boundary method is used to represent a spherical bubble. At the same time, the authors have built a numerical model to directly simulate the motion of finite size bubbles to assess the effect of homogeneous shear disturbances on the horizontal movement of bubbles. The analysis of the numerical model shows that the finite-sized clean bubbles have the direction of horizontal traversal reversal in uniform shear motion. Comparing the results with those for contaminated bubbles, it is found that the transverse migration in the reversed direction is more pronounced for clean bubbles.

In this study, the roles of non-uniformity Er (i.e its shear plus curvature) effects on the edge transport barrier formation are experimentally investigated. we have identified the mechanisms centered around the role of the Er-curvature on the edge transport barrier (ETB) formation. In addition, we recognized a new role of the Er-shear as for the expansion of pedestal width, compensating an unfavorable effect of the Er-curvature having its sign dependence on the turbulence transport.

We adopt the modified embedded atom potentials based classical molecular dynamics in combination with the similar atomic environment method to investigate the effects of different short-range orders on the mechanical behaviors of NiCoFeCr under the tensile and shear load conditions. Results indicate that the tensile and shear loads induce the elastic deformation, non-evenly yield deformation, and evenly plastic deformation. The formation of partial dislocations and stacking faults' core as well as the twin is the key factor of plastic deformation. The short-range order enhances the strength of NiCoFeCr.

Equations are derived for slip in a disordered atomic layer which describe diffusive creep as well as high-speed slip at low temperatures. An exact solution for the slip velocity is found in the form of a functional of the distribution function of the threshold shear stresses in the slip layer. The relationship between the microscopic parameters of the theory and the macroscopic properties of metallic glass is established in terms of the Mott intergrain slip model. The calculated rate of deformation of bulk metallic glass is compared with published experimental data.

Radial electric field shear is crucial for turbulence suppression and transition to the H-mode, although the high shear value alone may not be sufficient for the LH-transition initiation. Temporal and spatial parameters of shear perturbation, particle source and turbulence parameters are the main factors responsible for LH-transition initiation. Different plasma discharge scenarios in two Ioffe Institute conventional tokamaks are analyzed using the model of plasma density and ion temperature evolution to clear up the role of aforementioned factors.Radial electric field shear is crucial for turbulence suppression and transition to the H-mode, although the high shear value alone may not be sufficient for the LH-transition initiation. Temporal and spatial parameters of shear perturbation, particle source and turbulence parameters are the main factors responsible for LH-transition initiation. Different plasma discharge scenarios in two Ioffe Institute conventional tokamaks are analyzed using the model of plasma density and ion temperature evolution to clear up the role of aforementioned factors.

The impact of magnetic field and couple stress for the shear waves in an anisotropic, thinly layered laminated medium is explored. The frequency equation for the problem has been attained to determine the shear wave velocity using linear inhomogeneties. Several particular cases have been investigated. The numerical computation for distinct values of rigidity parameter, density parameter, anisotropic factor, initial stress parameter, magnetic field parameter and wave number. The results are graphically represented using MATLAB.

In the modern world many buildings have irregular configurations both in elevation and plan. Such types of buildings are more susceptible in earthquake forces. Structural irregularities are more important factors which decrease the seismic behavior of the structures. Buildings with slab openings are often vulnerable to damages, when subjected to lateral loads. The influence of diaphragm openings on the seismic response of multi-storied buildings played a major role in reducing the base shear, hence attracting lesser seismic forces. Correct location of openings can offer efficient strength and serviceability to the structure. It is necessary to identify performance of the structures to withstand against disaster for both new and existing buildings. Opening in the floors is common for many reasons like stair cases, lighting architectural etc., these openings in diaphragms cause stresses at discontinues joints with building elements. Discontinuous diaphragms are designed without stress calculations and are thought about to be adequate ignoring any gap effects. In this study an attempt has been made to know the difference in seismic response of two building having diaphragm discontinuity and without diaphragm discontinuity. In the present study existing building with diaphragms irregularity has been modeled and seismic response will be compared with building without diaphragm discontinuity using CSI SAP200 software. Linear static and dynamic analysis has been carried out. Results of two building have been compared for modal time period, base shear, storey drift and joint displacement.

Advanced high strength steel (AHSS) sheets have gained major attention from research groups across the world especially in last two decades. The exact description of the forming behavior of these steels has several challenges associated with it. The origin of these challenges is related to the complexity of the forming behavior and the failure characteristics of AHSS sheets at macro and micro scales. In the present study, deformation behavior and failure characteristics of two important AHSS sheets, DP and TRIP steels, subjected to different deformation modes are investigated at different scales. It is shown that these steels fail mostly by shear localization and an attempt to calculate the critical failure strains is proposed.

This paper analyzes numerically the mechanical behavior of geological depth structures in the Yenisei Ridge. For creating the computer structures of the researched area, the two geological profiles of “Shpat” and “Batolit-1982” obtained by deep seismic sounding were taken as a basis. To model plastic deformation, the Nikolaevsky elasto-plastic model was used. The depth analysis of the state of stress and strain was realized making use of the inelastic strain increments and the Lode parameter. The maximum values of strain increments are focused in upper layers of Earth’s crust, where pressure is lower, and also in the region of the Yenisei shear belt. The view of the Lode parameter distribution closely depends on the variation of strength properties with depth in the lithosphere. The stress state of the geological profiles “Shpat” and “Batolit-1982” is very heterogeneous, that is caused not only by the difference of physical and mechanical properties of lithosphere layers but the change of the geomedia strength with depth as well.

Experimental studies on the response of samples to dynamic loading were performed using a split Hopkinson-Kolsky bar and in a series of perforation tests. In-situ investigations of the thermodynamics of deformation processes made it possible to identify the characteristic deformation localization stages. Temperature fields were recorded with a high-speed infrared camera CEDIP Silver 450M, and strain localization in the samples was evaluated with a strain noninvasive measurement system StrainMaster. Temperature measurements made in the localization zone did not support a generally accepted concept that the strain localization mechanism is the mechanism governed by thermoplastic instability. The microstructural analysis of the samples stored after the experiment was carried out using an optical interferometer-profilometer and a scanning electron microscope. The analysis revealed the correlated behavior of the ensemble of defects, which can be classified as a structural transition providing strain localization. The data of experimental studies, the examination of the structure of deformed samples, as well as the data of numerical modeling performed with consideration of the kinetics of accumulation of microdefects in the material suggest that one of the mechanisms of plastic strain localization at high loading rates is associated with the jump-like processes in the defect structure of the material.

The methodology for development a nonlinear defining relation for a unidirectional carbon fiber reinforced plastic (CFRP) was proposed. The methodology is based on the analysis of stress-strain curves at different strain rates and loadings at different angles to the reinforcement direction. The study is based on the relations of the hereditary theory of elasticity and the anisotropic theory of elasticity using the Volterra principle and the properties of resolvent operators. Physical nonlinearity was taken into account by applying the Rabotnov curve of nonlinear deformation using piecewise linear approximation.The methodology for development a nonlinear defining relation for a unidirectional carbon fiber reinforced plastic (CFRP) was proposed. The methodology is based on the analysis of stress-strain curves at different strain rates and loadings at different angles to the reinforcement direction. The study is based on the relations of the hereditary theory of elasticity and the anisotropic theory of elasticity using the Volterra principle and the properties of resolvent operators. Physical nonlinearity was taken into account by applying the Rabotnov curve of nonlinear deformation using piecewise linear approximation.

Research on the velocity of shear wave velocities has been done around the Colomadu sub-District and Ngemplak sub-District. This study aims to obtain an average value of vs30 in order to find out the classification of subsurface structures in the study area. This research was carried out at the geographical coordinates of 7°32′34.9″S - 7°31′05.8″S and 110°44′43.9″E - 110°47′12.1"E, 12 site locations with an average ±1.5 km distance between sites. We used seismopragh Lennartz LE-3d lite for data acquisition. The processing data using geopsy software to get the H/V curve and get the value of the dominant frequency (fo) and amplitude (Ao), the data is used as input to the ellipticity curve method to obtain the shear wave velocity (vs) results from ground profiles using several input parameters as initialization initial value such as, P wave velocity (vp), poisson ratio, S wave velocity (vs), and density. The shear wave velocity profile is obtained through Rayleigh wave inversion. Shear wave velocity values up to 30 meters depth are expressed as vs30. From this study, the distribution of vs30 around Colomadu subdistrict and Ngemplak subdistrict ranged from (166,34 – 328,34) m/s. Based on the classification of the National Earthquake Hazards Reduction Program (NEHRP) the type of soil in the area is as classified E and D which is in the classification of soft soil and rigid soil types.

The paper obtains an exact solution describing the shear convection of a swirling viscous incompressible fluid in a horizontal layer taking into account the Marangoni condition, the Navier condition and the non-uniform pressure distribution on one of the layer boundaries. It is shown that this exact solution is able to describe the appearance of the stratification of a velocity field and thermal force fields. © 2019 Author(s).

Thin composite panels of asymmetric structure post-buckling behavior problem solutions for compression and shear are derived. Presented relationships can be used for analytic estimation of non-linear stress state of defect of delamination type. Also a method of load-bearing composite panels design by post-buckling state providing static strength criteria limitations is shown.

In this paper, an experimental campaign is described. The high purity Nickel sheet with a thickness of 500 microns is tested at low triaxiality. Thanks to a novel geometry, the axial tensile force is converted to shear the material in a local region. Different series of tests are carried out in function of grain sizes. A strong influence on the global mechanical response can be observed due to different numbers of grains through the thickness of sample. The experimental curves are reproduced by finite element simulations with an isotropic macroscopic Hollomon constitutive law relying on different sets of parameters. Next, a small representative volume is considered. Using the identified parameters for each grain size, a sandwich approach is applied. The results of the single constitutive law approach and the sandwich approach are compared.

In the paper, we discuss an approach to the development of methods for managing seismotectonic deformation processes in a multiscale block-structured Earth’s Crust from the viewpoint of the concept of physical mesomechanics. To date, there are no convincing results of many year researches in the fields of earthquake prediction and prevention of the dangerous man-caused and tectonic earthquakes. Therefore, in recent decades, there has been an increasingly active search for new ways to solve the problem of seismic safety. The aim of our research team’s activity is to provide a scientific rationale for a multidisciplinary approach to reduce the excess level of shear stresses in the fault zones to a safe background level by “spending” it on mechanical destruction and thermal processes in rocks during aseismic and co-seismic slip. The authors summarize the main results of modeling of geological and geophysical processes in the field of preparation of different scale seismogenic events, as well as the results of complex man-made impacts on segments of seismically active faults. The data obtained on segments of different scale faults within the Baikal rift zone and Mongolia confirm the possibility of implementing such an approach. For the practical implementation of such a project at highly stressed fault zones, it is necessary to carry out vertical, oblique and horizontal multilateral drilling with an injection of fluids of different compositions in combination with vibro-pulse stimulations to achieve safe relaxation of shear stresses.

The influences in the experimental investigation are divided into the geometry of the specimen and the corrosion phenomenon. The 8-element specimens were joined with various overlaps in the form of a single lap shear load multi-element specimen. Afterwards, the multi-element specimens were segmented into one-element specimens, which were tested under quasistatic shear load in order to detect possible influences of the specimen geometry. The effect of corrosion on the load-bearing capacity was investigated with the same multi-element specimen according to VDA 621-415. In addition, two arrangements of corrosion protection were generated in order to guarantee the joint quality in a corrosive surrounding atmosphere. It was found that the load-bearing capacity of specimens as well as the joint characteristics can be ensured using corrosion protection. The study gave a recommendation for planning the shear-clinching on a flange facing and showed promising potential for shear-clinching when joining multi-element specimens.

A microstructure model to describe the viscoelasticity and thixotropy properties of complex fluids is proposed. The model is based on the Lodge–Yamamoto network theory and is an extension of the Phan-Thien–Tanner model, with a kinetic process in which specific forms of creation and destruction rates are assumed. The final equation is simple with a small number of empirical parameters required and can be conveniently employed in engineering simulations. The predictions based on the model in a variety of shear and oscillatory shear flows are given. The stress response obtained from the model prediction agrees well with experiments on both shear and oscillatory flow histories.

A quasi-two-dimensional shear layer is produced by merging two gravity-driven flows of soap film at different average velocities. The Kelvin–Helmholtz instability dominates the evolution of the shear layer, similar to what is observed in three-dimensional shear layers. However, the constraints that effectively limit the flow to two spatial dimensions have a considerable influence on the development of secondary instabilities and transition to turbulence. Nearly 40 cm downstream in the flow, two two-dimensional instabilities are observed, namely, vortex-pairing and secondary Kelvin–Helmholtz instability. The development of secondary instabilities and transition to turbulence in the flow is also affected by the interaction of the flowing soap film with boundary layers forming in the air surrounding the flowing soap film in the direction normal to the plane of the film. This becomes apparent when the flow is analyzed quantitatively in terms of the mixing interface length and fractal dimension. Initially, the mixing interface length grows exponentially with the downstream distance; however, beyond a certain distance, the growth stops. For the fractal dimension of the mixing interface in our quasi-two-dimensional shear layer, we have observed a peak value of 1.27 as compared to 1.34 reported in the literature for a corresponding section of a three-dimensional shear layer. For scales larger than ∼1 cm, interaction with air begins to dominate as the leading mechanism of dissipation. Coupling with boundary layers in air near the soap film drains energy from the large flow features and apparently “freezes” its evolution, producing “fossil” turbulence at large downstream distances.

Dynamics of compound drops is central in several emerging applications including emulsion-fueled direct injection, targeted drug delivery, and the development of mechano-sensitive artificial cells. These applications are commonly hallmarked by high shear rates in confined fluidic environments. In the present work, we depict the role of the transverse electric field in controlling the resulting morpho-dynamics, including non-monotonic topological evolution and pinch-off phenomenon. In a tightly confined domain, we further show that the critical value of the electric field for triggering the pinch-off phenomenon may be greatly reduced as compared to larger-sized conduits. Finally, we portray a non-trivial variation of the drop pinch-off time with the degree of domain confinement, as attributed to the complex electro-hydrodynamic coupling over small scales. These results may turn out to be critical in manipulating the shape evolution of bio-mimetic soft matter in physiologically relevant fluidic pathways and on-chip applications.

The nonlinear evolution of the m/n = 2/1 double tearing mode (DTM) is investigated by the toroidal resistive magnetohydrodynamic code CLT. It is found that the m/n = 2/1 DTM can lead to either a core pressure crash or an off-axis pressure crash. Unlike the core pressure crash, the plasma pressure at the magnetic axis remains almost unchanged during the off-axis pressure crash. The pressure crash only occurs in the annular region during the off-axis crash, and the on-axis plasma pressure slowly reduces after the crash, which is consistent with TFTR observations. A series of simulations are carried out to investigate the influence of the radial position of the inner resonant surface r 1, the magnetic shear at the inner resonance surface, and the spatial separation between the two resonant surfaces on nonlinear behaviors of DTMs. We find that r 1 plays a dominant role in the nonlinear DTM behaviors. It is more likely for the DTM to lead to the core pressure crash with a smaller r 1. It is also found that the magnetic shear at the inner resonant surface and the spatial separation between the two resonant surfaces can also largely influence the nonlinear evolution of the DTM. A simple theoretical formula of the transition criterion between the two pressure crashes is proposed, which agrees well with the simulation results.

This work employs the second-order fluid model to investigate the effect of first and second normal stresses on the motion of spheroidal particles in unbound parabolic flows, where particles migrate toward the flow center. We specifically examine the effects of fluid Weissenberg number Wi and the ratio of normal stress coefficients α = ψ2/ψ1. Previous works have considered the motion of spheroidal particles in the co-rotational limit (α = −0.5), where the effect of fluid viscoelasticity is to modify the fluid pressure but not the shear stresses. Here, we examine all ranges of α that are found for functional complex fluids such as dilute polymer solutions, emulsions, and particulate suspensions and determine how viscoelastic shear stresses alter particle migration. We use perturbation theory and the Lorentz reciprocal theorem to derive the O(Wi) corrections to the translational and rotational velocities of a freely suspended spheroid in an unbound tube or slit flow. Our results show that for both prolate and oblate particles, the viscoelasticity characterized by α significantly affects the particle cross-stream migration, but does not qualitatively change the trends seen in the co-rotational limit (α = −0.5). For a range of α (−0.9 ≤ α ≤ 0) investigated in this work, particles possess the largest mobility when α = −0.9 and smallest mobility when α = 0. Although α does not alter particle rotation at a given shear rate, we observe significant changes in particle orientation during migration toward the flow center because changes in migration speed give rise to particles experiencing different shear histories.

The linear instability of a surfactant-laden two-layer falling film over an inclined slippery wall is analyzed under the influence of external shear, which is imposed on the top surface of the flow. The free surface of the flow and the interface among the fluids are contaminated by insoluble surfactants. Dynamics of the fluid layers are governed by the Navier–Stokes equations, and the surfactant transport equations regulate the motion of the insoluble surfactants at the interface and free surface. Instability mechanisms are compared by imposing the external shear along and opposite to the flow direction. A coupled Orr–Sommerfeld system of equations is derived using the perturbation technique and normal mode analysis. The eigenmodes corresponding to the Orr–Sommerfeld eigenvalue problem are obtained by employing the spectral collocation method. The numerical results imply that the stronger external shear destabilizes the interface mode instability. However, a stabilizing impact of the external shear on the surface mode is noticed if the shear is imposed in the flow direction, which is in contrast to the role of imposed external shear on the surface mode for a surfactant-laden single layer falling film. Furthermore, in the presence of strong imposed shear, the overall stabilization of the surface mode by wall velocity slip for the stratified two-fluid flow is also contrary to that of the single fluid case. The interface mode behaves differently in the two zones at the moderate Reynolds numbers, and higher external shear magnifies the interfacial instability in both zones. An opposite trend is observed in the case of surface instability. Moreover, the impression of shear mode on the primary instability is analyzed in the high Reynolds number regime with sufficiently low inclination angle. Under such configuration, dominance of the shear mode over the surface mode is observed due to the weaker impact of the gravitational force on the surface instability. The shear mode can also be stabilized by applying the external shear in the counter direction of the streamwise flow. Conclusively, the extra imposed shear on the stratified two-layer falling film plays an active role in the control of the attitude of the instabilities.

Red blood cells (RBCs) in physiological conditions are capable of deforming and aggregating. However, both deformation and aggregation are seldom considered together when modeling the rheological behavior of blood. This is particularly important since each mechanism is dominant under specific conditions. To address this void, we herein propose a new model that accounts for the deformability of red blood cells, by modeling them as deformed droplets with a constant volume, and of their aggregation, by properly characterizing the network formed by red blood cells under small shear rates. To derive the model, we employ non-equilibrium thermodynamics that allows us to consistently couple the two mechanisms and guarantees model admissibility with the thermodynamic laws. Relative to our previous model, which addresses the rheological behavior of non-aggregating deformable red blood cells, one additional structural variable, λ, to properly characterize the network formed by RBCs, and another additional parameter, ε, that quantifies the relative importance between the regeneration/buildup and flow-induced breakup of the network, are considered here. The new model predicts a yield shear stress, in accord with experimental data, but also predicts non-vanishing yield normal stresses. Although no rheological measurements of yield normal stresses of blood have been reported in the literature, the recent measurement of yield normal stresses of other yield stress fluids indicates their potential existence in blood as well. We show that the new model is in complete accord with the experimental rheological behavior of normal blood in both steady-state and transient (step-change in shear-rate) simple shear.

The energetic molecular crystal cyclotetramethylene-tetranitramine (HMX) is used in plastic bonded explosives, and reaction initiation and detonation are usually triggered by plastic deformation. However, the mechanism of plastic deformation in β-HMX, which is the HMX phase stable in ambient conditions, is still a matter of debate. A recent observation that pressure developing under shock conditions inhibits dislocation activity, leaves shear localization as the main deformation mechanism in this crystal at high pressures and strain rates. In this work, the steady state shear band viscosity is evaluated as a function of the applied pressure, temperature, and shear strain rate using atomistic models of the HMX crystal. The viscosity of a fully formed shear band decreases as a power function of the strain rate and decreases linearly with increasing temperature, demonstrating shear thinning and non-Arrhenius behavior. The viscosity increases with increasing pressure. The fully formed band behavior is independent of the crystallographic orientation. It is shown that viscosity can be expressed exclusively in terms of the density of the non-crystalline material in the band, and hence the results can be explained in terms of the excess free volume theory developed for shear bands in other material systems, e.g., metallic glasses. The stress required to nucleate a shear band from a straight pre-existing dislocation is reported as a function of the applied pressure, temperature, and strain rate.

In this work, the frame-invariant formulation of a new generalized Newtonian fluid (GNF) constitutive equation is proposed. Viscosity is considered as a specific function of the second and third invariant of the strain rate tensor and of the second invariant of the objective velocity gradient. The GNF model was successfully tested using experimental data taken from the open literature for different high and low density polyethylene melts with varying amounts of long-chain branches utilizing steady-state shear, uniaxial, and planar extensional viscosities plotted as a function of the strain rate.