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In this paper, the accurate free vibration characteristics of thin-walled box beam are discussed and the kinematic model is established by using fine shear deformation theory. The model adopts the in-plane and out-of-plane displacement fields including extension, torsion, warping and distortion, as well as the transverse shear due to bending and warping due to torsion. One-dimensional high-order beam theory is applied to the dynamic solution of thin-walled box beam, and the analytical solution of high free vibration modes of multi-deformation coupled modes under different boundary conditions is derived. The results show that warping, distortion and shear deformation play an important role in the free vibration characteristics of thin-walled box beam, and the validity of the model is verified. In addition, finite element software (ANSYS) is used for finite element simulation. The application of vibration mode in the structure design of thin-walled box beam is summarized, especially in the case of higher natural frequency. The calculation method is in good agreement with the finite element results. [ABSTRACT FROM AUTHOR]

The shear deformation of the steel strip layer is introduced for the first time into the constitutive model of steel strip reinforced thermoplastic pipes (SSRTP), aiming to obtain a more precise solution for the burst pressure. Five SSRTP specimens with end fittings were employed to conduct the burst pressure test. Accordingly, two sets of FE models which are friction-inclusive and friction-neglecting were established. The friction-inclusive FE model demonstrates good agreement with the test solution, while the friction-neglecting FE model aligns well with the theoretical solution. The findings indicate that for wide strip layers, the shear deformation is not negligible. The impacts of additional tensile armour, winding angle, and friction coefficient on the burst pressure were analyzed. Finally, a linear correction is applied to account for the influence of the friction coefficient, yielding a result that can be regarded as the lower limit of the SSRTP's burst pressure. [ABSTRACT FROM AUTHOR]

Hypothesis : Amphiphilic diblock copolymers are known to increase the surfactant's efficiency to stabilize microemulsion, leading to higher structural order and monolayer rigidity. We thus seek to evaluate whether the addition of such polymers alters the shear behavior of bicontinuous microemulsions, in particular, their shear transformation towards lamellar structures. Experiments : We examine the initial structure and shear response of bicontinuous ▪/ n -octane/▪/PEP 5 - b -PEO 5 microemulsions by coupling microfluidics with small-angle neutron scattering (SANS), attaining wall shear rates in excess of ▪. The azimuthal analysis of the obtained 2D scattering patterns allows us to follow their structural transformation by means of the degree of anisotropy. Findings : The amphiphilic diblock copolymer promotes the shear-induced transformation of bicontinuous microemulsions, resulting in up to ∼▪ higher degrees of anisotropy than for corresponding polymer-free microemulsions. The increased shear response observed with increasing polymer content is rationalized by combining the influence of domain size and viscosity with the stability limits of the bicontinuous microemulsion in the isothermal phase diagram. As a result, a consistent description of the degree of anisotropy is obtained, enabling the prediction of the shear-induced bicontinuous-to-lamellar transformation. [ABSTRACT FROM AUTHOR]

This study is based on a theory for analyzing non-uniform torsion in thin-walled beams made of homogeneous elastic material with arbitrary cross-sections by incorporating the effect of the shear deformation of a cross-section. Utilizing the Finite Element Method (FEM), the proposed numerical approach addresses non-uniform torsion by breaking down a 3D analysis into 2D cross-sectional and 1D modeling components. Initially, the geometric constants of the cross-section were computed using a 9-node isoparametric element in 2D FEM. Subsequently, a 1D FEM employing a linear isoparametric element calculated the twist angle, torsion warping parameters, and stress results. The stress field was determined through a local analysis of the 2D cross-section. Notably, the 2D FEM component aligns with contemporary trends in commercial software, thereby bolstering the potential and practical applicability of the proposed numerical approach. Its verification and validation through numerical analyses using MATLAB underscore the efficacy and reliability of the method in analyzing non-uniform torsion behavior in structural design, particularly under diverse boundary conditions. [ABSTRACT FROM AUTHOR]

The study was initiated for the consistent mass matrix of Euler beam element including shear deforma-tion. The consistent mass matrix of uniform element was got separately for the uncoupled tension, torsion, and ben-ding conditions, with the shear deformation included or not, based on the shape functions and the virtual work. It was shown that the inertia force along the axial direction was always ignored in the mass matrix derivation for the bending condition if the shear deformation was not included, so only the shape functions for vertical deformation were needed for the bending condition. When the shear deformation was included, the inertia force along the axial direction must be considered and the shape functions for the section rotation angle due to bending were also required besides the complete shape functions for vertical deformation due to the bending and shear forces. For tapered Euler element, the theoretical expression for the consistent mass matrix would be quite complicated and a simple expression was proposed following an approximate strategy, matching the ending or average section areas or polar moments with the elements in the mass matrix according to their positions. Additionally, the stiffness matrix could also be deduced on the foundation of the complete shape functions for vertical deformation and the shape functions for the section rotation angle. This derivation procedure was different with the traditional manner superficially but they shared the same principle essentially. [ABSTRACT FROM AUTHOR]

Periodic composite beams play an important role in the bandgap design of phononic crystals. However, for thick beams or high frequencies, conventional theoretical displacement assumptions for beams have limitations. Therefore, it is desirable to improve the accuracy of the vibration frequencies and bandgaps of phononic crystals by using higher-order beam theory. In this work, a modified couple stress theory accounting for the microstructure effect is combined with the third-order shear deformation beam theory to quantitatively study bandgaps in phononic crystal microbeams under different thicknesses and geometric parameters. The elastic wave band structure of the phononic crystal beams is calculated using an improved plane wave expansion method and compared numerically with the finite element model. In addition, compared with the Bernoulli–Euler and Timoshenko beams, the current third-order shear beam has better prediction accuracy for the first bandgap. The numerical results also show that the microstructure effect is significant at the micron scale. Furthermore, at all length scales, the bandgap sizes change significantly with the change in unit cell length and volume ratio. [ABSTRACT FROM AUTHOR]

The continuous retained-mandrel rolling process is a promising method for titanium tube production with high efficiency and a short process. The importance of mandrel as a deformation tool supporting the inner wall is crucial. This paper thoroughly examines the influence of mandrel velocity on the deformation characteristics at the groove vertex using three approaches: numerical simulation, shear-deformation observation experiments, and microstructure analysis. The following conclusions are drawn: Decreasing the mandrel velocity enhances the penetration of shear deformation into the inner wall of the titanium tube, improves thickness uniformity, and shifts the deformation mechanism near the inner wall from twinning to dislocation slip. As a result, the volume fraction of recrystallization increases from 18.4% to 42.3%. However, the mean shear strain increases first and then decreases to a certain value as the mandrel speed decreases, which is attributed to the combined influence of the cross-shear zone and the rolling force. [ABSTRACT FROM AUTHOR]

An Element Free Galerkin (EFG) meshless formulation and solutions using higher order shear deformation theory with nine degrees of freedom for the static analysis of Functionally Graded Material (FGM) plates are provided. This technique estimates the shape function using Moving Least Squares (MLS) method. The proposed method is validated by comparing the present findings with those in the literature. A novel Artificial Neural Network (ANN) model is developed to forecast the deflection of FGM plates within less computational time. Detailed parametric and convergent studies reveal that the proposed EFG solution and the ANN technique are more efficient than their conventional counterparts. The validation and comparison of the generated results in the present investigation with the other analysis methods revealed that the EFG method and ANN model give more accurate results than the FEM and other meshless methods. The current EFG-ANN model reduces computing time by 99.94% when compared to the EFG approach. Also, the accuracy is enhanced using the EFG approach with HSDT9 for the FGM plate. [ABSTRACT FROM AUTHOR]

The present study investigates free vibration analysis of cylindrical panels made of porous orthotropic layers. Porous material properties are modeled using uniform and two non-uniform porosity distribution patterns through the thickness. The theoretical formulations are expressed based on the higher-order shear deformation theory. The equations of motion of laminated cylindrical panels are established by performing Hamilton's principle. These fundamental partial differential equations are solved analytically for the laminated cylindrical panels, which are simply supported on all edges. Galerkin's solution procedure is applied to obtain the natural frequency equation. The natural frequencies are compared to results in the literature to verify the obtained frequency equation. Afterward, novel parametric studies are developed to discuss the influence of porosity parameters, porosity distribution patterns, geometrical parameters, orthotropy, and lamination sequences on the free vibration response of porous laminated cylindrical panels. [ABSTRACT FROM AUTHOR]

Shear deformation mechanisms of diamond-like carbon (DLC) are commonly unclear since its thickness of several micrometers limits the detailed analysis of its microstructural evolution and mechanical performance, which further influences the improvement of the friction and wear performance of DLC. This study aims to investigate this issue utilizing molecular dynamics simulation and machine learning (ML) techniques. It is indicated that the changes in the mechanical properties of DLC are mainly due to the expansion and reduction of sp3 networks, causing the stick-slip patterns in shear force. In addition, cluster analysis showed that the sp2-sp3 transitions arise in the stick stage, while the sp3-sp2 transitions occur in the slip stage. In order to analyze the mechanisms governing the bond breaking/re-formation in these transitions, the Random Forest (RF) model in ML identifies that the kinetic energies of sp3 atoms and their velocities along the loading direction have the highest influence. This is because high kinetic energies of atoms can exacerbate the instability of the bonding state and increase the probability of bond breaking/re-formation. Finally, the RF model finds that the shear force of DLC is highly correlated to its potential energy, with less correlation to its content of sp3 atoms. Since the changes in potential energy are caused by the variances in the content of sp3 atoms and localized strains, potential energy is an ideal parameter to evaluate the shear deformation of DLC. The results can enhance the understanding of the shear deformation of DLC and support the improvement of its frictional and wear performance. [ABSTRACT FROM AUTHOR]

Adiabatic shearing represents a prevalent mode of deformation failure in metals when subjected to impact loading. In this work, dynamic shearing interruption tests considering various shear displacements (i.e., shear strains) were conducted on of the CoCrFeNi high-entropy alloy (HEA) produced by laser powder bed fusion (LPBF) to analyze the microstructural evolution during adiabatic shearing. From the results, it was observed that the columnar grains in the shear region only distorted to different degrees at the lower levels of shear strain. Then, it was also found that the increase in shear strain caused severe distortion and refinement of the columnar grains, ultimately leading to adiabatic shearing band (ASB) at a critical shear strain threshold. During inhomogeneous deformation at high strain rate, the ASB formation was predicated on enough plastic deformation work. The interconnection between microstructural softening mechanisms and macroscopic mechanical behavior during ASB evolution and fracture was also highlighted. The nano-sized equiaxed recrystallized grains within the ASB were formed by rotational dynamic recrystallization (RDRX) rather than migratory recrystallization. Moreover, a large number of nano-twins were formed in these nano-sized recrystallized grains to motivate the mechanism of slip within nano-twins, thus accommodating the continuous plastic deformation. These results are the main reasons for the outstanding resistance to shear deformation of CoCrFeNi HEA produced by LPBF.

This research article focuses on achieving water security in hilly terrains through the identification of suitable sites for rainwater harvesting reservoirs near habitations. The study was conducted in the planned geological park (PGP) location within Sikkim University (SU) campus, utilizing a multi-faceted approach that combined geological, geophysical, and geotechnical methodologies. The analysis of ALOS-P DEM revealed the absence of streamflow within SU campus, ruling out direct water recharge options. However, the planned geological park (PGP) location exhibited a gentle slope and receives an annual average precipitation (ERA) of 1215 mm indicating potential for rainwater harvesting. Geological fieldwork excluded densely fractured areas, involving data collection on soil and rock types, joint analysis, soil sampling, and Schmidt hammer tests. Geophysical fieldwork provided insights into fracture zones, layer depth, and fracture orientation. Incorporating data into a non-linear finite element model allowed to assess shear, deformation, and safety factors, identifying Site A as most suitable due to higher stability compared to Sites B and C. The key innovation lies in the integration of scientific methodologies. The combination of geological, geophysical, and geotechnical data, in the study has presented a holistic approach to site identification, ensuring a comprehensive understanding of the terrain’s hydrological characteristics.

In this paper, the first‐principles method is used to calculate the electronic structure of the intrinsic WSe2 system and the Ca adsorbed WSe2 system under shear deformation, and the diffusion barrier of Ca on WSe2 is studied in depth. The results show that shear deformation can effectively reduce the band gap of WSe2 system, and shear deformation can easily lead to the transition from semiconductor properties to metal properties. The adsorption of Ca leads to the change of the band structure of WSe2. The contribution of Ca‐d electrons leads to an increase in the peak in the range of 3–6 eV. The shear deformation reduces the diffusion barrier of Ca on the WSe2 surface. This paper provides an improvement method for the application of WSe2 in the field of battery. [ABSTRACT FROM AUTHOR]

Copyright of Railway Construction Technology is the property of Railway Construction Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Our study investigates the interaction of dislocations with hexagonal close-packed (hcp) and chi-phase (χ) particles in body-centred cubic (bcc) tungsten (W) using molecular dynamics simulations. The research aims to understand how these interactions influence the mechanical properties of W, particularly in the context of neutron irradiation environments. The simulations were conducted with spherical and cylindrical particles at various temperatures and cell sizes to observe the effects on critical shear stress. Results indicate that the shape and size of the particles significantly affect the critical shear stress required for dislocation movement, with cylindrical particles requiring higher stresses than spherical ones. Additionally, the study found that temperature variations have a more pronounced effect on χ-phase particles compared to hcp-phase particles. Our findings provide insights into the strengthening mechanisms in W-Re alloys and suggest potential pathways for enhancing the material's performance under extreme conditions. [ABSTRACT FROM AUTHOR]

The lack of a bandgap in stanene severely limits its outstanding characteristics in optoelectronic devices. Using first-principles calculations, we systematically investigate the effects of full hydrogenation and shear deformation on the electronic structure and optical properties of stanene. Hydrogenation exerts a remarkable impact on electronic structure of stanene, enabling surface state transition from quasi-metallic to semiconducting. Shear degrades the structural stability of full-hydrogenated stanene (FHstanene). FHstanene exhibits a tunable bandgap of 1.327 eV, which can be further reduced to 0.719 eV through shear deformation. The presence of spin-orbit coupling (SOC) induces band splitting in FHstanene. The maximum optical absorption of FHstanene occurs at 291 nm, while the reflectance peak is observed at 449 nm. The variation in bandgap due to deformation results in a redshift in the absorption coefficient and reflectance, and shear deformation increases the reflectance of FHstanene. These findings broaden the application prospects of stanene in novel nano-optoelectronic devices. [ABSTRACT FROM AUTHOR]

This study aims to analyze the free vibration of an ogival arch in which two symmetrical arched shapes are discontinuously met at the mid-arc. Differential equations governing the free vibration of an ogival circular arch were derived, where the rotatory inertia and shear deformation effects are included. The governing equations were numerically solved to calculate natural frequencies and mode shapes. In numerical solution methods, the symmetric and anti-symmetric boundary conditions at the mid-arc were focused rather than the boundary conditions of supported end due to the discontinuity of the mid-arc. For the first time, the free vibration problem for discontinuous arches, such as ogival arches, is solved in this study. Calculation results of this study for natural frequencies are compared well with those of the finite element method. The effects of various arch parameters on natural frequencies were highlighted and discussed in detail. [ABSTRACT FROM AUTHOR]

Analogous electrical networks were previously derived from the Euler–Bernoulli and Kirchhoff–Love theories to represent beams and plates, respectively, for use in multimodal structural vibration damping. However, these networks do not account for shear deformations or rotary inertia, which can result in suboptimal vibration damping performance when used on moderately thick beams and plates. In this paper, we investigate the incorporation of shear deformation and rotary inertia using Timoshenko–Ehrenfest beam theory and Mindlin–Reissner plate theory to develop improved electrical networks that can more accurately represent thick beams and plates. Our findings suggest that the inclusion of shear deformation and rotary inertia can significantly improve the frequency coherence of the electrical networks and multimodal vibration damping for thicker structures. The electrical analogs presented here are of use for various applications, especially to conveniently design complex circuit topologies in fields spanning from vibration attenuation to energy harvesting. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Computational Mechanics / Jisuan Lixue Xuebao is the property of Chinese Journal of Computational Mechanics Editorial Office, Dalian University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The impact of shear deformation on texture evolution in strip-cast Fe-1.5%Si non-oriented electrical steel was studied combined with in-suit experiments and crystal plasticity finite element method (CPFEM). Throughout the deformation process, the texture evolution predominantly follows a traditional route: transitioning from {211} and {411} to {111} orientation. In certain regions with specific stress conditions, orientation evolution shifts from {310} to {411}, {100}, and finally to {100} orientation. Crystal plasticity finite element (CPFE) simulation results show that the rotation of {310} through {411} to {100} orientation, {211} and {112} orientations transition to {111} and {110} orientations, respectively, which is consistent with the experimental observations. Recrystallization texture mainly includes favorable λ and near-λ (∥ND, normal direction) textures, with detrimental γ (∥ND) texture essentially diminishing. In-situ heating experiments revealed {411} as the primary recrystallization orientation, the mechanism involves both oriented nucleation and growth. In the edge region lacking stress constraints, the Schmid factor (SF) reaches up to 0.48, the (21-3)[111] slip system is preferentially activated, with shear bands appearing earlier in the same region. Indicating that when slip mechanism alone are inadequate for sustaining plastic deformation, the shear deformation becomes the favored mode of activation. {411} orientation can serve as a transitional orientation for transitioning to {100} orientation, and further as an advantageous transitional orientation during the nucleation and growth of recrystallization. Due to the texture improvement, superior magnetic properties were achieved, with the average magnetic induction (B50) and iron loss (P1.5/50) being 1.77 T and 4.25 W/kg, respectively.

In order to study the evolution of fracture permeability under shear action, a Weierstrass random fractal function was used in Comsol to generate a single fracture, and the relative displacements of two fracture surfaces were adjusted to simulate shear action. Changes of fracture width under different shear displacements and the defined range of nonlinear effects under different flow rates were analyzed, the factors affecting fracture permeability in shear process were determined by using scatter plot and function curve fitting, and the quantitative relationship was given. The results show that the probability density distribution of the gap width meets the standard Gaussian distribution without shearing, but with the shearing process, the Gaussian distribution of the gap width is destroyed and only reflects parts of the characteristics of the standard Gaussian distribution. When the shear occurs, the permeability first has a decreasing process, and then fluctuate within a certain range. The smaller aperture is unfavorable to the water flow through near the contact area. When Re>9.6, the fluid begins to develop from linear to nonlinear. The influence of fracture aperture on fluid seepage characteristics during shear deformation of single fracture of rock is simulated, which provides some reference for analyzing the geothermal change caused by fracture deformation in geological bodies.

As shear stress plays a significant role in the deformation of tubular parts with complex shapes, investigation of the microstructue evolution of tubes under the shear stress state is beneficial to understanding the shear deformation mechanism and promoting the prediction accuracy of numerical simulation. In this paper, the shear experiments were conducted on thin-walled 5052 aluminum alloy tubes. The texture evolution and lattice rotation behavior of the tube during shear deformation were studied using in-situ electron back scatter diffraction (EBSD) technology. It is shown that the initial Cube texture remains stable, while a new Rot. Copper texture is formed in the shear deformation zone. The grains with the orientation of parallel to the axial direction (AD) tend to stabilize, while several low-angle grain boundaries (LAGBs) are formed inside the grains with unstable initial orientations. Notably, the orientations of adjacent grains are more similar after shear deformation, and the high-angle grain boundaries (HAGBs) gradually transform to LAGBs showing the characteristics of polycrystalline cooperative deformation. By analyzing the lattice rotation mechanism under shear stress, it is found that the shear stress promotes the lattice rotation to a stable orientation parallel to the direction of the shear stress. This research provides theoretical guidance for predicting the forming of tubular parts with complex shapes.

Context: In this study, the electronic structure and diffusion barrier of Ca adsorbed MoTe2 system under different degrees of shear deformation were calculated based on the first-principles method. The results show that both the pure MoTe2 system and Ca-adsorbed MoTe2 system are affected by shear deformation. The pure MoTe2 undergoes a transition from direct to indirect band gap under shear deformation. The adsorption of Ca makes MoTe2 changes from semiconductor to quasi-metal. The results of the density of states show that Ca insertion makes the conduction band part of the adsorption system significantly enhanced. The diffusion barrier of Ca through MoTe2 indicates that the shear deformation promotes the diffusion of Ca on the surface of MoTe2. Shear deformation can effectively modulate the electronic properties of the MoTe2 system, which provides a theoretical basis for the application of MoTe2 materials in the field of ion batteries. Methods: In this study, Materials Studio 8.0 software was used to construct the MoTe2 model and Ca adsorbed MoTe2 model, and the CASTEP module was used for first-principles calculation. [ABSTRACT FROM AUTHOR]

In this study, the heterogeneous strengthening behavior in shear deformation was experimentally characterized and numerically modeled for the first time. Uniaxial tensile and simple shear tests were conducted to evaluate the mechanical behavior of Al/Steel/Al layered sheet and its monolithic layers. Contrary to expectations, the mechanical behavior of the layered sheet showed more outstanding performance compared to a simple calculation of the rule of mixtures in not only tensile deformation but also shear deformation, proving the heterogeneous strengthening effect in shear deformation as well. Moreover, the yield strength showed similar synergies in tensile and shear deformations, but the shear deformation exhibited a higher additional strengthening effect at the load before reaching fracture. This remarkable outcome is primarily attributed to the formation of a large amount of geometrically necessary dislocations near the heterogeneous interface in shear deformation than at tensile maximum load. Meanwhile, microstructure and deformation mechanism-based constitutive models were applied to finite element simulations of tensile and shear deformations. The numerically predicted stress–strain curves were compared to experimental results, indicating that microstructure-based constitutive models are reasonable for shear stress state as well as uniaxial tension state. Furthermore, dislocation density-based hardening model is better than conventional phenomenological isotropic hardening for extrapolation of large strain in simple shear test. This is mainly due to consideration of microstructural features in dislocation density-based hardening model. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Hebei University of Science & Technology is the property of Hebei University of Science & Technology, Journal of Hebei University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents a novel analytical formulation to study the impact of shear deformations on beam-columns and piles by means of the Timoshenko-Engesser’s and Timoshenko-Haringx’s theories. The proposed solution enables the analysis of lateral deformation or buckling, while considering the effect of shear deformations. It offers the flexibility to i) incorporate different boundary conditions at the ends of the element (e.g., semi-rigid connections and lateral transverse springs) and ii) consider an inhomogeneous elastic foundation. When certain variables are disregarded, the proposed GDE can capture particular cases of GDEs found in the literature for beam-columns and piles. Examples are provided to demonstrate the simplicity and practicality of the proposed method, and its accuracy is validated against available analytical or numerical methods. The influence of the shear effects, as computed from Engesser’s and Haringx’s methods, on the lateral and buckling responses of beam-column and pile elements is discussed.

Structural changes in polylactide/polybutylene terephthalate (PLA/PBT) and glycol‐modified polyethylene terephthalate/polybutylene terephthalate (PET‐G/PBT) polymer blends at a pressure of 1 GPa and room temperature in combination with shear deformation are investigated. High pressure torsion (HPT) is chosen as the compatibilization technique. Based on solid‐state NMR data, it is found that the compatibility of immiscible polymers is significantly improved under high pressure conditions in combination with shear deformation. It is assumed that the thickness of the deformed polymer layers decreases to the thickness of the interphase and it can be a fully interphase material. [ABSTRACT FROM AUTHOR]

The article presents methods for improving the quality of forgings and workpieces obtained by forging by intensifying shear or alternating strain in the bulk of the deformed metal. To increase the metal processing due to shear or alternating strain during forging, forging strikers are most often used, the feature of which is the geometric configuration that creates additional metal flows. Quite a lot of works from research teams from all over the world have been devoted to the problem of intensive metal processing during forging. In these publications, a number of new unique designs of strikers have been proposed and various route technologies have been considered, which can significantly increase the level of shear or alternating strain compared with the use of traditional forging tool designs.

The continuous retained-mandrel rolling process is a promising method for titanium tube production with high efficiency and a short process. The importance of mandrel as a deformation tool supporting the inner wall is crucial. This paper thoroughly examines the influence of mandrel velocity on the deformation characteristics at the groove vertex using three approaches: numerical simulation, shear-deformation observation experiments, and microstructure analysis. The following conclusions are drawn: Decreasing the mandrel velocity enhances the penetration of shear deformation into the inner wall of the titanium tube, improves thickness uniformity, and shifts the deformation mechanism near the inner wall from twinning to dislocation slip. As a result, the volume fraction of recrystallization increases from 18.4% to 42.3%. However, the mean shear strain increases first and then decreases to a certain value as the mandrel speed decreases, which is attributed to the combined influence of the cross-shear zone and the rolling force.

Casing deformation occurs frequently in shale gas wells, resulting in the failure of some fracturing stages to complete normal operations, which seriously affects shale gas production. This paper firstly analyzes the casing deformation mechanism of shale gas wells and determines that the casing shear deformation caused by formation slip is the main factor of casing deformation. In order to solve the problem of casing shear deformation, a finite element numerical model including the formation, cement ring, and the casing is established. The casing shear deformation caused by formation slip is simulated, and the deformation results obtained are consistent with those measured in the actual wellbore. Based on the numerical model, a casing deformation governance method is proposed to optimize the wellbore trajectory and adjust the cement ring properties. It is calculated that reducing the dip angle á of the formation and casing vertical direction and reducing the formation slip is beneficial to reducing casing deformation. The use of low elastic modulus cement and uncementing operations can provide a buffer space for formation slip, effectively reduce casing deformation, and provide an effective treatment method for shear deformation of shale gas wells. [ABSTRACT FROM AUTHOR]

Based on the first-order shear deformation theory (FSDT), the large-amplitude vibration behavior of shallow spherical shells made of functionally graded materials (FGMs) due to the rapid decrease of temperature (cooling shock) is investigated. FGM is assumed to be a mixture of stainless steel and low-carbon steel whose properties are considered temperature dependent and are estimated based on the power-law model. According to FSDT and von Kármán assumptions, the governing equations of motion in conjunction with corresponding boundary conditions are obtained using Hamilton's principle. The temperature distribution is also achieved by means of the 1D Fourier transient heat conduction equation, considering two time-dependent thermal loading scenarios. The considered thermal boundary conditions allow that a temperature difference is created with a time delay for the structure under cooling shock. Also, the results of recent experiments are employed to estimate the temperature-dependent properties of structures. In the solution approach, the generalized differential quadrature method and the Newmark-beta integration scheme are utilized. Selected numerical results are presented to study the effects of thermal load rapidity time, geometry, magnitude of thermal load, and material gradient index on the thermally induced vibrations of spherical shells. Stresses generated in the shell due to the thermally induced vibrations are also investigated. [ABSTRACT FROM AUTHOR]

The accuracy of a wavelet depends on the choice of the mother wavelet adopted. The present work aims to predict the free vibration behavior of laminated sandwich plates using wavelet finite element (WFE). Different kinds of mother wavelets, namely, B-spline wavelet on the interval (BSWI), Gaussian, Haar, Daubechies 6 (db6), Biorthogonal 3.7 (bior3.7), Coiflet5 (coif5), Symlets (sym8), Morlet, Mexican hat (Mh), and Meyer mother wavelets, are employed in WFE for predicting the frequencies. Both symmetric and unsymmetric laminates are studied using the proposed approaches. A wide range of problems, including the influence of the geometric and material properties and end conditions on the free vibration behavior of the laminated sandwich plates, are solved. The effectiveness of the WFE over the conventional finite element method in terms of computational efficiency is discussed. In conclusion, BSWI-based WFE method (WFEM) is found to be the most accurate and computationally efficient in predicting the free vibration behavior of laminated sandwich plates. The accuracy of the WFEM depends widely on the type of mother wavelet adopted. [ABSTRACT FROM AUTHOR]

The neotectonic processes are crucial for identification of active faults in a seismic unstable area. The Aїn Smara active fault runs along the Middle Rhumel Valley located in Constantine area of Algerian Eastern Tell Atlas mountain chain and it emerges in the south‒western part of the epicentral zone of the earthquake occurred on October 27, 1985 (Mw = 5.8) within a corridor displaying morphological features and deformed Pliocene‒Quaternary layers, which are the consequence of transpressive tectonic regime. In our study the morpho-tectonic and structural research supported by the fieldwork, was performed. The thick fault gouge indicating simple shear deformation, fault breccias and minor faults affecting the Pliocene limestone and Quaternary alluvial terraces, were found. The active fault splits into northern and southern segments. The northern segment corresponds to the El Aria Fault that ruptured during the earthquake in 1985 and the southern segment with the studied Aĭn Smara Fault. Our research showed the significant extent of the active fault and including its parameters for improved seismic hazard assessment of the Constantine area. [ABSTRACT FROM AUTHOR]

Context: In this study, the electronic structures and optical properties of the pure MoSe2 and O-doped MoSe2 systems under different shear deformations are calculated based on the first-principles approach. It is hoped to provide new possibilities for the design of novel controllable optoelectronic devices and to provide guidance for the application of MoSe2 in the field of optoelectronic devices. The findings indicate that both pure MoSe2 and O-doped MoSe2 systems are somewhat impacted by shear deformation. The pure MoSe2 undergoes a transition from direct to indirect and then to direct bandgap under shear deformation, but still maintains the semiconductor properties. The bandgap of the doped system changes from a direct to an indirect bandgap at 8% shear deformation. According to the examination of the density of states, we find that the density of states of the pure MoSe2 system is mainly contributed by the Mo-d and Se-p orbitals, and the total density of states of the system after O-atom doping mainly originates from the results of the contributions of the Mo-d, Se-p, and O-p orbitals. Optical property analysis reveals that the conductivity and peak value of the pure MoSe2 system are gradually red-shifted toward the low-energy region with the increase of shear deformation. The dielectric function of the O-doped MoSe2 system is red-shifted in the region of 6~10% shear deformation, and the degree of red-shift rises with deformation amount. The findings demonstrate that the electrical structure and optical characteristics of the O-doped MoSe2 system may be modulated effectively by shear deformation, providing a theoretical foundation for expanding the usage of MoSe2 materials in the field of optoelectronic devices. Methods: This study is founded on the CASTEP module in the Materials-Studio software within the first-principles of the density-functional theory framework. The photoelectric properties of the intrinsic and doped systems under shear deformation are calculated using the Perdew-Burke-Ernzerh (PBE) of generalized function under the generalized gradient approximation (GGA). The Monkhorst-Pack special K-point sampling method is used in the calculations, and a 5 × 5 × 1 K-point grid is used for the calculations with a plane-wave truncation energy of 400 eV in the optimization of the structure of each model. After geometrical optimization, the energy convergence criterion for each atom is 1 × 10−5 eV/atom, the force convergence criterion is 0.05 eV/Å, and a vacuum layer of 20 Å in the c-direction is set. [ABSTRACT FROM AUTHOR]

In this research, the deflection in the interface of a partially composite beam considering the effect of shear deformation is determined. The system of beams is structured by two beams of prismatic sections, connected by an adhesive very thin and rigid, subjected to a uniform bending moment and a uniformly distributed load. The governing differential equation of the partially composite beam is obtained from the total functional energy that takes into consideration the shear deformation. The extreme moments creating second moments, shear forces and normal forces are applied to each beam. The differential equation is derived and then, compared to the one found in partial composite beams where the shear deformation is neglected. It is shown that the theoretical results of deflection with and without shear deformation are compared to each other and also with those found in the Timoshenko's beam theory. [ABSTRACT FROM AUTHOR]

Natural fractures may not be developed in hot dry rock reservoirs, and tectonism or fracturing can induce the shear deformation of fractures and result in large-scale rough-walled fractures. Previous studies usually ignore the effect of rough walls on production performance. This study constructs a 3D multiwell enhanced geothermal system (EGS) model with two rough-walled fractures after shear deformation, systematically investigates the response characteristics of each physical field under the thermo–hydro–mechanical coupling, and determines the effect of the distribution of two rough-walled fractures and the relationship between the well layout scheme and the shear deformation direction on the production performance. The obtained results indicate that the distribution and evolution of the temperature and seepage fields are controlled by the fractures. The stress has a clear impact on the fracture permeability, up to approximately four times the initial permeability. The water preferentially extracts the heat from the reservoir rock between fractures. When the intersecting angles of fractures are 10° and 30°, there exists a sufficient heat exchange domain and a shorter average distance between fractures, which can enhance the production efficiency. The well layout perpendicular to the shear deformation direction is conducive to delaying the lifespan of the EGS and extracting more heat over a longer exploitation time. These key results can provide reasonable suggestions for the optimal development strategy in EGSs. [ABSTRACT FROM AUTHOR]

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Context: In this study, the effects of different shear deformations on the structural stability, electronic structure, and optical properties of a Mg atom adsorption system of S vacancy defect SnS2 are systematically investigated based on density functional theory. It is shown that the presence of an S-vacancy defect makes the band gap of the SnS2 system significantly smaller than that of the perfect SnS2 system, and the SnS2 system is changed from a direct band gap semiconductor to an indirect band gap semiconductor. The optimal adsorption position of a Mg atom on the S-vacancy SnS2 system is above the S atom where the adsorption energy is the largest and the system is the most stable. The density of states of the adsorption system is predominantly contributed by the S-3p and Sn-5 s orbital electrons. The imposition of shear deformation leads to the introduction of certain impurity energy levels in the adsorption system, and the forbidden bandwidth near the Fermi energy level decreases. As compared to the intrinsic SnS2, the absorption and reflection peaks of adsorption systems under different shear deformation are red-shifted and appear in the ultraviolet region. This improves the utilization of the adsorption system for ultraviolet light to a great extent. Methods: The model calculations in this paper are performed using the CASTEP module of the Material Studio (MS) software based on the first principles of Density Functional Theory (DFT) (Wei et al. in Physica B 545:99–106, 2018) for plane wave artifacts. Geometrical optimization and computational procedures are used to calculate the exchange–correlation energy using the Perdew-Burke-Ernzerhof (PBE) generalized function (Perdew et al. in Phys Rev B Condens Matter 48:4978, 1993) of the generalized gradient approximation (GGA). The Monkhorst–Pack method (Monkhorst and Pack in Phys Rev B 13:5188–5192, 1976) was used to rationalize the sampling of the highly symmetric k-points in the Brillouin zone. The grid of k-points is set to be 6 × 6 × 1. The plane-wave truncation energy is set to be 400 eV. The energy convergence criterion is 1.0 × 10−5 eV. The residual stress of all atoms is 0.01 eV/Å. A vacuum layer with a thickness of 15 Å is set up in the z-direction, which ensures that the interactions of the system along the z-axis between the top and the bottom layers can be ignored during the whole simulation process. We construct a 3 × 3 × 1 SnS2 system containing 27 atoms as the computational model. The intrinsic SnS2 contains 9 Sn atoms and 18 S atoms. [ABSTRACT FROM AUTHOR]

This paper proposes a simple method for calculating the shear deformation and the shear capacity of reinforced and prestressed concrete elements containing shear reinforcement. This new approach considers that, for large deformations, concrete elements follow compatibility conditions based on displacements of the composite material subjected to shearing forces. The result is a beam, inspired by the Timoshenko-Ehrenfest beam theory, which considers a new hypothesis regarding shearing deformation, informed by the behavior of the shear reinforcement. The new method is compared with previous approaches, allowing us to assess the technological advances of the new proposal. The new method is easy to implement and provides information about the shearing deformation (in the elastic and plastic domains) and the shearing capacity of concrete beam-column elements. A detailed example is developed, in which all the components of the shear deformation are evaluated, and the simplification of the new method is analyzed in comparison with other more comprehensive methods in the elastic domain. [ABSTRACT FROM AUTHOR]

Context: In this study, the effects of different shear deformations on the structural stability, electronic structure, and optical properties of a Mg atom adsorption system of S vacancy defect SnS2 are systematically investigated based on density functional theory. It is shown that the presence of an S-vacancy defect makes the band gap of the SnS2 system significantly smaller than that of the perfect SnS2 system, and the SnS2 system is changed from a direct band gap semiconductor to an indirect band gap semiconductor. The optimal adsorption position of a Mg atom on the S-vacancy SnS2 system is above the S atom where the adsorption energy is the largest and the system is the most stable. The density of states of the adsorption system is predominantly contributed by the S-3p and Sn-5 s orbital electrons. The imposition of shear deformation leads to the introduction of certain impurity energy levels in the adsorption system, and the forbidden bandwidth near the Fermi energy level decreases. As compared to the intrinsic SnS2, the absorption and reflection peaks of adsorption systems under different shear deformation are red-shifted and appear in the ultraviolet region. This improves the utilization of the adsorption system for ultraviolet light to a great extent. Methods: The model calculations in this paper are performed using the CASTEP module of the Material Studio (MS) software based on the first principles of Density Functional Theory (DFT) (Wei et al. in Physica B 545:99–106, 2018) for plane wave artifacts. Geometrical optimization and computational procedures are used to calculate the exchange–correlation energy using the Perdew-Burke-Ernzerhof (PBE) generalized function (Perdew et al. in Phys Rev B Condens Matter 48:4978, 1993) of the generalized gradient approximation (GGA). The Monkhorst–Pack method (Monkhorst and Pack in Phys Rev B 13:5188–5192, 1976) was used to rationalize the sampling of the highly symmetric k-points in the Brillouin zone. The grid of k-points is set to be 6 × 6 × 1. The plane-wave truncation energy is set to be 400 eV. The energy convergence criterion is 1.0 × 10−5 eV. The residual stress of all atoms is 0.01 eV/Å. A vacuum layer with a thickness of 15 Å is set up in the z-direction, which ensures that the interactions of the system along the z-axis between the top and the bottom layers can be ignored during the whole simulation process. We construct a 3 × 3 × 1 SnS2 system containing 27 atoms as the computational model. The intrinsic SnS2 contains 9 Sn atoms and 18 S atoms. [ABSTRACT FROM AUTHOR]

During the Northridge earthquake, extensive brittle failures on the weld zones of the beam bottom flanges in the rigidity connection of steel special moment frames (SMFs) were detected. One of the primary reasons is the high-tensile strain demand created at the beam bottom flange zones due to positive bending. The weak panel zone of the I-section column exhibits more shear deformation, which promotes and accelerates the brittle fracture of the beam bottom flange weld zones. A box-strengthened panel zone can minimize the shear deformation of the panel zone of the I-section column, which may also reduce the inter-story displacement of steel SMFs and enhance their seismic behavior. In order to investigate this fact, in this research we carried out a model test of a steel frame with a box-strengthened panel zone to examine SMFs' seismic performance and inter-story displacement, as well as testing the contribution of panel zone shear deformation to inter-story drift. Numerical methods were then used to investigate the influence of the axial compression ratio and beam-to-column linear stiffness ratio on the effect of shear deformation on the box-strengthened panel zone. Design recommendations are given based on the research results. [ABSTRACT FROM AUTHOR]

In this study, a full view of the shear location was presented and ultrafine grain structure with excellent thermal stability during 700–850 °C was obtained through cold shearing and heat treatment of martensitic Cr4Mo4Ni4V steel. The results reveal that initial martensite blocks were refined through local rotating the elongated blocks into small grains in the shear region with effective strain 2–2.5. Driven by the shear deformation and heat treatment, ferrite recrystallization (about 1 μm) bands formed in the shear region mainly through continuous recrystallization at 700–850 °C, and mixed-grain structure (6.2 μm in average) formed at 1000 °C. Interestingly, the size and distribution of carbides in the shear region and undeformed region exhibited a dramatic difference due to the ultrafine recrystallization. This study provided information regarding achieving stable ultrafine grain structure through cold shearing and heat treatment of Cr4Mo4Ni4V martensitic steel.

In this study, a variable cross-sectional flexible pin of a megawatt wind turbine gearbox is taken as the research object, and the deflection curve equation of the variable cross-sectional flexible pin considering the influence of shear deformation is established. The deflection equation and slope-deflection equation of the variable cross-sectional flexible pin are obtained by using the Green's function method. The effectiveness of this method is verified by comparing with the calculation results of the engineering algorithm and the finite element method. The simulation model of the wind power gearbox is established using Romax software, and it is verified that the deformation characteristics of the variable cross-sectional flexible pin can improve the load distribution and load sharing coefficient. The influence of the supporting stiffness of the pin and gear mesh misalignment on the load sharing performance is investigated. The research results provide a theoretical basis for improving the load sharing performance of the wind turbine gearbox and the design optimization of the variable cross-sectional flexible pin.

Our study investigates the interaction of dislocations with hexagonal close-packed (hcp) and chi-phase (χ) particles in body-centred cubic (bcc) tungsten (W) using molecular dynamics simulations. The research aims to understand how these interactions influence the mechanical properties of W, particularly in the context of neutron irradiation environments. The simulations were conducted with spherical and cylindrical particles at various temperatures and cell sizes to observe the effects on critical shear stress. Results indicate that the shape and size of the particles significantly affect the critical shear stress required for dislocation movement, with cylindrical particles requiring higher stresses than spherical ones. Additionally, the study found that temperature variations have a more pronounced effect on χ-phase particles compared to hcp-phase particles. Our findings provide insights into the strengthening mechanisms in W-Re alloys and suggest potential pathways for enhancing the material’s performance under extreme conditions.