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Dynamic analysis of electrorheological fluid sandwich cylindrical shells with functionally graded face sheets using a semi-analytical approach
, Article Composite Structures ; Volume 295 , 2022 ; 02638223 (ISSN) ; Haddadpour, H ; Shakhesi, S ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The present research is performed to calculate the natural frequencies, loss factors, and associated mode shapes of a sandwich cylinder with moderately thick functionally graded (FG) face sheets and an electrorheological (ER) fluid core. Each face sheet is assumed to be made of FG materials, and its displacement field is estimated based on the first-order shear deformation theory, like the ER constrained layer. A suitable displacement continuity condition is considered between layers. The ER fluid used in the central middle is analyzed in the pre-yield area and considered electric field dependent. Hamilton's principle is used to acquire the motion equations related to each layer and...
Deformation and creep characteristics of AA7075-T76 at elevated temperatures
, Article Journal of Materials Engineering and Performance ; Volume 31, Issue 9 , 2022 , Pages 7586-7595 ; 10599495 (ISSN) ; Serajzadeh, S ; Sharif University of Technology
Springer
2022
Abstract
In this work, deformation behavior as well as creep and cavitation of AA7075-T76 were studied. The as-received plate was first stabilized utilizing solution treatment followed by two-stage artificial aging at 120 and 180 °C. Then, tensile tests were carried out on the aged-alloy in the temperature range between 120 and 250 °C under strain rates of 0.0005 and 0.005 s−1. Furthermore, stress-controlled creep tests were performed at temperatures varying between 120 and 210 °C at stresses ranging from 130 to 250 MPa. Microstructural evolution was then conducted to assess the microstructural changes and growth of cavities during creep employing optical metallography and scanning electron...
Vibration of a Circular plate on Pasternak foundation with variable modulus due to moving mass
, Article Structural Engineering and Mechanics ; Volume 83, Issue 6 , 2022 , Pages 757-770 ; 12254568 (ISSN) ; Foyouzat, M. A ; Mofid, M ; Sharif University of Technology
Techno-Press
2022
Abstract
In this paper, the vibration of a moderately thick plate to a moving mass is investigated. Pasternak foundation with a variable subgrade modulus is considered to tackle the shortcomings of Winkler model, and an analytical-numerical solution is proposed based on the eigenfunction expansion method. Parametric studies by using both CPT (Classical Plate Theory) and FSDT (First-Order Shear Deformation Plate Theory) are carried out, and, the differences between them are also highlighted. The obtained results reveal that utilizing FSDT without considering the rotary inertia leads to a smaller deflection in comparison with CPT pertaining to a thin plate, while it demonstrates a greater response for...
Development of consistent fish-bone simplified model with energy-based approach for efficient seismic evaluation of irregular steel moment resisting frames
, Article Soil Dynamics and Earthquake Engineering ; Volume 161 , 2022 ; 02677261 (ISSN) ; Ahmadie Amiri, H ; Esmailpur Estekanchi, H ; Kheirkhah Gildeh, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
This study aims to develop the Consistent Fish-Bone (CFB) simplified model for efficient estimation of Engineering Demand Parameters (EDPs) in irregular steel Moment Resisting Frames (steel-MRFs). To achieve this goal, some modifications based on the energy consistent approach have been applied to the Improved Fish-Bone (IFB) simplified model previously presented for reinforced concrete MRFs. These modifications include: 1) adding truss elements to the IFB model to consider the effect of flexural deformations and determining their areas by balancing the overturning moment and the strain energy due to the axial deformation of columns in the original steel-MRF with the overturning moment and...
Mathematical modeling of anisotropic hyperelastic cylindrical thick shells by incorporating thickness deformation and compressibility with application to arterial walls
, Article International Journal of Structural Stability and Dynamics ; Volume 22, Issue 13 , 2022 ; 02194554 (ISSN) ; Asghari, M ; Sharif University of Technology
World Scientific
2022
Abstract
This paper is devoted to mathematical modeling of anisotropic hyperelastic thick cylindrical shells like arteries by taking into account the volume compressibility and through-the-thickness deformation. To describe the hyperelastic behavior of this kind of shells and extract their constitutive relations, the modified anisotropic (MA) model is employed, which is able to characterize compressible behavior of hyperelastic materials like soft tissues. By considering the arterial segment as a thick cylindrical shell, the higher order thickness deformation shell theory together with nonlinear Green's strains are exploited to express its deformations and capture the thickness stretching effect. The...
Theoretical analysis of rotary hyperelastic variable thickness disk made of functionally graded materials
, Article Structural Engineering and Mechanics ; Volume 45, Issue 1 , 2022 , Pages 39-49 ; 12254568 (ISSN) ; Mahdavi Adeli, M ; Zamani, F ; Haghshenas Gorgani, H ; Sharif University of Technology
Techno-Press
2022
Abstract
This research investigates a rotary disk with variable cross-section and incompressible hyperelastic material with functionally graded properties in large hyperelastic deformations. For this purpose, a power relation has been used to express the changes in cross-section and properties of hyperelastic material. So that (m) represents the changes in cross-section and (n) represents the manner of changes in material properties. The constants used for hyperelastic material have been obtained from experimental data. The obtained equations have been solved for different m, n, and (angular velocity) values, and the values of radial stresses, tangential stresses, and elongation have been compared....
Large deformation of shape-memory polymer-based lattice metamaterials
, Article International Journal of Mechanical Sciences ; Volume 232 , 2022 ; 00207403 (ISSN) ; Jebellat, E ; Roudbarian, N ; Mohammadi, K ; Movahhedy, M. R ; Asle Zaeem, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Through advanced computational analysis, this work demonstrates that metamaterial structures when made by shape-memory polymers (SMPs) can provide unique intelligent mechanical behavior. For the first time, geometrical effects, pertaining to low and ultra-low densities, on the thermomechanical behavior of SMP-based octet-truss lattice meta-structures are studied in this work. A reliable constitutive thermo-visco-hyperelastic model is applied to analyze the shape-memory behavior of several designed octet-truss lattices with ultra-low and low relative densities, ranging from 0.04 to 0.23. Different compressive strain values are tested to determine the effect of pre-straining. It is concluded...
A micro mechanical study on tensile behavior of steel sheets with spheroidal cementite using crystal plasticity finite element method
, Article Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications ; Volume 236, Issue 12 , 2022 , Pages 2357-2371 ; 14644207 (ISSN) ; Assempour, A ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
In this research, we investigate the effects of various microstructural features on the behavior of spherical steel sheets, using the crystal plasticity finite element method. The cementite phase ratio, the grain sizes of ferrite and cementite, and the percentage of residual pearlite in the steel structure due to incomplete annealing are the major microstructural parameters studied in this work. A grain generator software has been developed to generate hexagonal ferrite grains as well as circular cementite particles distributed in the ferrite matrix. We use a hard coating with special properties as an intermediate layer around the cementite grains to simulate the contact between ferrite...
A new look at tensile yielding in isotactic polypropylene: role of strain rate and thermal softening
, Article Polymer Bulletin ; Volume 79, Issue 12 , 2022 , Pages 11157-11176 ; 01700839 (ISSN) ; Bagheri, R ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Polypropylene (PP) is a semi-crystalline polymer with a very wide range of industrial applications. This is why its mechanical properties, including yielding, have been the subject of numerous studies. The current study has examined the influence of strain rate and thermal softening on yield stress and post yielding behavior of an isotactic PP. A two-process Ree and Eyring model and the heat equation in adiabatic deformation were coupled with a physical parameter described as the temperature sensitivity of the flow stress at yielding, to simulate the effect of gradual temperature rise in adiabatic heating on yielding behavior. Along with that, tensile bars were subjected to tests at...
Dynamic simulation of the ultra-fast-rotating sandwich cantilever disk via finite element and semi-numerical methods
, Article Engineering with Computers ; Volume 38 , 2022 , Pages 4127-4143 ; 01770667 (ISSN) ; Habibi, M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
In the presented research, vibrational, and amplitude behaviors of a sandwich spinning disk made of two laminated layers and graphene nanoplatelets reinforced composite (GPLRC) core has been reported. The Coriolis and centrifugal impacts have been taken into account due to its rotational feature. The stresses and strains have been obtained through the high-order shear deformable theory (HSDT). The structure’s boundary conditions (BCs) are determined using laminated rotating disk’s governing equations employing energy methods and ultimately have been solved via a computational approach called generalized differential quadrature method (GDQM). The rotational disk’s vibrations with different...
Band-structure calculation of SH-waves in 1D hypersonic nano-sized phononic crystals with deformable interfaces
, Article Mechanics of Materials ; Volume 171 , 2022 ; 01676636 (ISSN) ; Shodja, H. M ; Sanati, M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Nanoscopic interface deformations between the layers in a superlattice have a great impact on its phononic band-structure. This work aims to study the SH-wave band-structure in one-dimensional (1D) multilayer hypersonic nano-sized phononic crystals with consideration of local deformations at the interfaces of the layers. At this scale, the traditional theory of elasticity is unable to capture the realistic forbidden and permitted frequencies. Thus, in light of surface/interface elastodynamics theory for nanostructures with deformable interfaces, a mixed variational method which accounts for the notion of interface elasticity, deformability, and inertia is introduced in the present work. For...
The effect of carbon on the restoration phenomena during hot deformation of carbon steels
, Article International Journal of Materials Research ; Volume 94, Issue 8 , 2022 , Pages 916-921 ; 18625282 (ISSN) ; Karimi Taheri, A ; Zebarjad, S. M ; Sharif University of Technology
Walter de Gruyter GmbH
2022
Abstract
A study has been made to determine the influence of the carbon content on the kinetics of dynamic and static recrystallization during and after hot deformation of carbon steels. For this purpose, single- and double-hit hot compression experiments at various strain rates and temperatures together with the Avrami-type kinetics equation and Bergstrom approach have been utilized to investigate recrystallization behavior. The results show that the apparent activation energy of hot deformation decreases with increasing carbon content and this phenomenon results in a faster dynamic recrystallization at high temperatures and/or low strain rates. Also, increasing carbon content leads to a higher rate...
Coupled continuum damage mechanics and crystal plasticity model and its application in damage evolution in polycrystalline aggregates
, Article Engineering with Computers ; Volume 38 , 2022 , Pages 2121-2135 ; 01770667 (ISSN) ; Assempour, A ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
In the present study, damage initiation and growth in a polycrystalline aggregate are investigated. In this regard, an anisotropic continuum damage mechanics coupled with rate-dependent crystal plasticity theory is employed. Using a thermodynamically consistent procedure, a finite deformation formulation is derived. For this purpose, the damage tensor is incorporated in the crystal plasticity formulation for a cubic single crystal. The damage evolution is considered to be dependent on the history of damage, equivalent plastic strain, stress triaxiality, and Lode parameters. This material model is implemented in the commercial finite-element code Abaqus/Standard by developing a user material...
Degradation behavior of the as-extruded and ECAP-processed Mg-4Zn alloy by Ca addition and hydrothermal coating
, Article Journal of Materials Research and Technology ; Volume 20 , 2022 , Pages 1204-1215 ; 22387854 (ISSN) ; Mohammadi Zerankeshi, M ; Nobakht Farin, F ; Alizadeh, R ; Mahmudi, R ; Sharif University of Technology
Elsevier Editora Ltda
2022
Abstract
Coating is an effective approach to address the high corrosion rate of biodegradable Mg alloys, as their main challenge toward their extensive use. In this regard, it was tried to control the degradation process of an Mg-4Zn alloy by Ca addition, equal channel angular pressing (ECAP), and hydrothermal coating. The obtained results indicated that excellent grain refinement induced by Ca incorporation and ECAP simultaneously, improved both mechanical strength and corrosion resistance of the Mg-based substrate. The achieved grain refinement resulted in a thicker, more compact and integrated coating, where the ECAP-processed Mg-4Zn-0.5Ca alloy exhibited the best coating quality with no...
Effects of resonator geometry and substrate stiffness on the tunability of a deformable microwave metasurface
, Article AEU - International Journal of Electronics and Communications ; Volume 146 , 2022 ; 14348411 (ISSN) ; Goudarzi, T ; Fleury, R ; Sohrabpour, S ; Naghdabadi, R ; Sharif University of Technology
Elsevier GmbH
2022
Abstract
Tunable metasurfaces can shift their resonant frequency through different approaches, one of which is applying mechanical deformations. Here, we show the effects of two key factors on the tunability of deformable metasurfaces; the resonator geometry and substrate stiffness. To show the effects, we compared the tunability of unit cells with three resonator geometries and three common substrates at microwave frequencies from 1 GHz to 10 GHz under a given mechanical deformation. We showed that the resonator geometry affects the deformation field, as a consequence, causes different resonant frequency shifts. Moreover, it affects the stress field in the metasurface which in turn limits the...
Study of microstructural growth under cyclic martensite phase transition in shape memory alloys; A molecular dynamics approach
, Article Journal of Intelligent Material Systems and Structures ; Volume 33, Issue 4 , 2022 , Pages 604-616 ; 1045389X (ISSN) ; Taghibakhshi, A ; Nejat Pishkenari, H ; Arghavani, J ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
Shape memory alloys are referred to as a group of alloys that can retrieve the permanent deformation and strain applied to them and eventually return to their original form. So far, various studies have been done to determine the behavior of these alloys under cyclic loading. Most of the studies have mainly been conducted by using the foundations of Continuum Mechanics in order to examine the properties of memory alloys. In this study, instead of using the Continuum Mechanics, a Molecular Dynamics simulation method using Lennard-Jones potential is utilized. The changes in the behavior and properties of memory alloy under cyclic loading are being examined. First, the functional form...
Investigation on dynamic stability and aeroelastic characteristics of composite curved pipes with any yawed angle
, Article Composite Structures ; Volume 284 , 2022 ; 02638223 (ISSN) ; Chen, J ; Duan, R ; Habibi, M ; Khadimallah, M. A ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
For the first time, in the current work, a dynamic stability analysis of a tilted curved pipe in a supersonic airflow under thermal loading is presented. The heat-transfer continuum problem is used for simulating the thermal environment conditions. The tilted pipe is reinforced by carbon nanotube agglomerations (CNTAs). For simulating the displacement fields of the current structure, Quasi-2D refined high order shear deformation theory is studied. The verification segment is divided into two parts. In the first and second sections, the credibility of the results of this study are confirmed by the results extracted using COMSOL multiphysics software and published articles in the literature,...
A comprehensive FE study for design of anchored wall systems for deep excavations
, Article Tunnelling and Underground Space Technology ; Volume 122 , 2022 ; 08867798 (ISSN) ; Pak, A ; Yousefi, M ; Aghakhani, N ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Anchored wall system is one of the common methods used for deep excavation stabilization adjacent to sensitive structures in urban areas. A key aspect of the stability analysis of deep excavations is the amount of deformations occurring on the facing wall and the adjacent structures. In this research, a large number of parametric studies considering all aspects of soil-structure interaction is carried out for different excavation geometries to find the optimal design, and the outcome is shown in the form of design tables and charts. Also, by a GA-PSO algorithm and using the large database obtained from the numerical simulations, a simple equation is developed that can predict the deflections...
Effect of mechanical nonlinearity on the electromagnetic response of a microwave tunable metamaterial
, Article Journal of Physics D: Applied Physics ; Volume 55, Issue 20 , 2022 ; 00223727 (ISSN) ; Goudarzi, T ; Fleury, R ; Orazbayev, B ; Naghdabadi, R ; Sharif University of Technology
IOP Publishing Ltd
2022
Abstract
Tunable metamaterials functionalities change in response to external stimuli. Mechanical deformation is known to be an efficient approach to tune the electromagnetic response of a deformable metamaterial. However, in the case of large mechanical deformations, which are usually required to fully exploit the potential of the tunable metamaterials, the linear elastic mechanical analysis is no longer suitable. Nevertheless, nonlinear mechanical analysis is missing in the studies of mechanically tunable metamaterials. In this paper, we study the importance of considering nonlinearity in mechanical behavior when analyzing the response of a deformable metamaterial and its effects on electromagnetic...
Geometry influence on fracture behavior of lap-shear solder joints
, Article IEEE Transactions on Components, Packaging and Manufacturing Technology ; Volume 12, Issue 1 , 2022 , Pages 80-88 ; 21563950 (ISSN) ; Nourani, A ; Honarvar, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
Single lap-shear (SLS) specimens of 63Sn37Pb solder joints were prepared with three different adherend thicknesses at three varying joint lengths. The fracture force was measured at a shear strain rate of 0.01 s-1 for different geometries. The elastic-plastic fracture mechanics (EPFM) theory was used to find the energy dissipated in each case using a finite element model (FEM), and the fracture energy was obtained by cohesive zone modeling (CZM). Both 2-D and 3-D models were used to explain the variations in fracture energy by the level of constraint on the joint. Also, the plastic zone area and stress distribution along the solder layer were calculated at the moment of fracture. A phase...