Search for: out-of-plane
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    Out-of-plane buckling of Y-braced frames with rigid joints

    , Article Proceedings of the Institution of Civil Engineers: Structures and Buildings ; Volume 166, Issue 1 , 2013 , Pages 28-37 ; 09650911 (ISSN) Zamani, M. S ; Vafai, A ; Kazemi, M.T ; Sharif University of Technology
    Because of the complicated buckling characteristics of Y-shaped bracings, calculation of their strength is beyond routine engineering procedures. A method based on slope-deflection equations incorporating stability functions has been used for computation of buckling eigenvalues and effective length factors. Lateral strength is computed based on the least buckling strength of bracing members. This study is limited to bracings with similar sections and fixed end connections resisting out-of-plane rotation. Lateral strengths predicted by the analytical method for two cases are compared with experimental results on full-scale specimens. It is shown that the proposed analytical method predicts... 

    Transverse resistance of masonry infills

    , Article ACI Structural Journal ; Volume 107, Issue 4 , 2010 , Pages 461-467 ; 08893241 (ISSN) Moghaddam, H ; Goudarzi, N ; Sharif University of Technology
    In this paper, a confined infill panel previously experimented under out-of-plane loading is modeled and analyzed by the dynamic explicit method (DEM). This method is shown to have a good estimation of the experimental results, and is thus adopted to investigate the out-of-plane behavior of an infill model. Based on the analytical results, the stress distribution of an infill panel prior to and after cracking, and the effect of an arching mechanism on post-cracking behavior, is studied. A semi-empirical relationship is accordingly developed for predicting the transverse resistance of masonry infills due to one-way arching action, which accounts for the effects of the boundary frame... 

    Bidirectional behavior of unreinforced masonry walls

    , Article Earthquake Engineering and Structural Dynamics ; Vol. 43, Issue 15 , 1 December , 2014 , pp. 2377-2397 ; ISSN: 00988847 Dolatshahi, K. M ; Aref, A. J ; Yekrangnia, M ; Sharif University of Technology
    Most of the studies related to the modeling of masonry structures have by far investigated either the in-plane (IP) or the out-of-plane (OP) behavior of walls. However, seismic loads mostly impose simultaneous IP and OP demands on load-bearing or shear masonry walls. Thus, there is a need to reconsider design equations of unreinforced masonry walls by taking into account bidirectional effects. The intent of this study is to investigate the bidirectional behavior of an unreinforced masonry wall with a typical aspect ratio under different displacement-controlled loading directions making use of finite element analysis. For this purpose, the numerical procedure is first validated against the... 

    Design and manufacturing of ultrasonic motor with in-plane and out-of-plane bending vibration modes of rectangular plate with large contact area

    , Article Measurement: Journal of the International Measurement Confederation ; Volume 109 , 2017 , Pages 425-431 ; 02632241 (ISSN) Dabbagh, V ; Sarhan, A. A. D ; Akbari, J ; Mardi, N. A ; Sharif University of Technology
    Ultrasonic motor working with coupled in-plane and out-of-plane vibration modes of rectangular plate is proposed and experimentally investigated. Thanks to its unique configuration, proposed motor provides large contact area between stator and rotor of motor which can reduce wear and enhance motor life-time. The proposed motor is designed using finite element method and according to the design, a prototype is fabricated and its working characteristics such as speed, normal and driving force and working frequency are measured. Overall dimension of designed prototype is 49 × 14 × 2 mm, working frequency of motor is 49.6 kHz, no-load speed and stall force of motor are 122 rpm and 0.32 mN m at... 

    In-plane and out-of-plane waves in nanoplates immersed in bidirectional magnetic fields

    , Article Structural Engineering and Mechanics ; Volume 61, Issue 1 , 2017 , Pages 65-76 ; 12254568 (ISSN) Kiani, K ; Gharebaghi, S. A ; Mehri, B ; Sharif University of Technology
    Techno Press  2017
    Prediction of the characteristics of both in-plane and out-of-plane elastic waves within conducting nanoplates in the presence of bidirectionally in-plane magnetic fields is of interest. Using Lorentz's formulas and nonlocal continuum theory of Eringen, the nonlocal elastic version of the equations of motion is obtained. The frequencies as well as the corresponding phase and group velocities pertinent to the in-plane and out-of-plane waves are analytically evaluated. The roles of the strength of in-plane magnetic field, wavenumber, wave direction, nanoplate's thickness, and small-scale parameter on characteristics of waves are discussed. The obtained results show that the in-plane... 

    Prediction of the bending and out-of-plane loading effects on formability response of the steel sheets

    , Article Archives of Civil and Mechanical Engineering ; Volume 21, Issue 2 , 2021 ; 16449665 (ISSN) Peng, D ; Chen, S ; Darabi, R ; Ghabussi, A ; Habibi, M ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Failure in sheet metal forming can occur by necking, fracture or wrinkling. By using a forming limit diagram (FLD) as a powerful tool to prevent sheets metal failures in the forming process, provides parameters controlling throughout forming. There are different developed methods for predicting FLDs, which estimate sheet metal forming strains limits. Assessment of FLD estimation reveals that there is a dependency between the effect of several factors containing normal stress, shear stress, sheet thickness, mechanical properties, metallurgical properties, yield function, strain path, and bending with formability. In this research, the effects of bending via two finite element models are... 

    Simulation of in Plane and Lateral Vibration of a Graphene Plate, Based on the Clasic Plate Theory and the most General form of Strain Gradient Theory and Deriving the Constitutive Law Parameters from Molecular Mechanic Parameters

    , M.Sc. Thesis Sharif University of Technology Hassanpour, Saba (Author) ; Dehghani Firouzabadi, Rohollah (Supervisor)
    Here the differential equations of a Graphene sheet deformation is determined by making use of the most general form of first Strain Gradient Elasticity (SGE) theory. In order to derive the equations of in-plane and out-of-plane deformations, the matrix representation of Strain Gradient constitutive law is used. Vibration of the nano-plate is studied by modeling the plate based on Kirchhoff theory and application of variation of energy, therefor the in-plane and out-of-plane vibration of the nano-plate is found through Navier analytical solution. After all natural frequencies are obtained based on SGE parameters. SGE parameters are determined by calculating the potential of a representative... 

    Transverse Retrofit of Infilled Frames with FRP

    , M.Sc. Thesis Sharif University of Technology Goudarzi, Nabi (Author) ; Moghaddam, Hassan (Supervisor)
    Masonry buildings are wide spread in Iran and some other countries . These buildings are highly vulnerable to seismic excitations if not constructed in accordance with engineering fundamentals . Thus it is necessary to retrofit these structures to flee from humanitarian and economical damages inflicted by earthquakes. One of the critical vulnerabilities of masonry buildings is due to transverse instability of it’s infills . Therefore to study out of plane behavior of these elements , an infilled frame is modeled and analyzed with ABAQUS , the results of which is in good congruence with the experimental one . In this model , stress distribution due to one way arching action in the confined... 

    Experimental Investigation the out of Plane Behavior of Masonry Walls Strengthened with Textile Reinforced Concrete (TRC)

    , M.Sc. Thesis Sharif University of Technology Abbasian, Navid (Author) ; Rahimzadeh Rofoei, Fayaz (Supervisor) ; Yekrangnia, Mohammad (Supervisor)
    In developing countries, one of the structural systems used for many buildings is the masonry system, and there are also many existing buildings worldwide with different uses constructed with this system, some of these buildings may have a major historical value and because of that, study of behavior of these buildings to find effective ways to improve their behavior is very important. In this study, the use of Textile Reinforced Concrete (TRC) for retrofit masonry walls is examined. For this purpose, seven scaled brick walls is used, including a test model, a model coated with plane concrete on one side of the wall, a model coated with plane concrete on both sides of the wall, a model... 

    Spatial limit cycles around the moon in the TBP

    , Article Acta Astronautica ; Volume 67, Issue 1-2 , 2010 , Pages 46-52 ; 00945765 (ISSN) Aram, A ; Zohoor, H ; Sohrabpour, S ; Sharif University of Technology
    Stable and unstable limit cycles are important orbits in chaotic systems. So many works are done to find and to quench chaos by stabilizing them. In this paper a new family of limit cycle orbits around the Moon is introduced as a result of restricted three-body problem. The family is completely spatial and can be used as an out-of-plane velocity magnifier. Lyapunov exponent in the Floquet theory has also been checked and stability of the orbits has been measured  

    Forming limit diagrams by including the M–K model in finite element simulation considering the effect of bending

    , Article Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications ; Volume 232, Issue 8 , 2018 , Pages 625-636 ; 14644207 (ISSN) Habibi, M ; Hashemi, R ; Ghazanfari, A ; Naghdabadi, R ; Assempour, A ; Sharif University of Technology
    SAGE Publications Ltd  2018
    Forming limit diagram is often used as a criterion to predict necking initiation in sheet metal forming processes. In this study, the forming limit diagram was obtained through the inclusion of the Marciniak–Kaczynski model in the Nakazima out-of-plane test finite element model and also a flat model. The effect of bending on the forming limit diagram was investigated numerically and experimentally. Data required for this simulation were determined through a simple tension test in three directions. After comparing the results of the flat and Nakazima finite element models with the experimental results, the forming limit diagram computed by the Nakazima finite element model was more convenient... 

    A new method for infill equivalent strut width

    , Article Structural Engineering and Mechanics ; Volume 69, Issue 3 , 2019 , Pages 257-268 ; 12254568 (ISSN) Tabeshpour, M. R ; Mahdipour Arasteh, A ; Sharif University of Technology
    Techno Press  2019
    Infills are as important members in structural design as beams, columns and braces. They have significant effect on structural behavior. Because of lots of variables in infills like material non-linear behavior, the interaction between frames and infill, etc., the infills performance during an earthquake is complicated, so have led designers do not consider the effect of infills in designing the structure. However, the experimental studies revealed that the infills have the remarkable effect on structure behavior. As if these effects ignored, it might occur soft-story phenomena, torsion or short-column effects on the structures. One simple and appropriate method for considering the infills... 

    An innovative infill wall utilizing light expanded clay aggregate: An experimental and numerical study

    , Article Structural Design of Tall and Special Buildings ; Volume 29, Issue 15 , 2020 Ghamari, A ; Khaloo, A ; Sharif University of Technology
    John Wiley and Sons Ltd  2020
    Past earthquakes had shown vulnerability of infill walls especially under out of plane (OOP) loading. Although some new infill walls show a good OOP performance, generally, they do not have the right economic justification or have complexity in construction. Therefore, in this paper, an innovative economical infill wall is presented that is not complicated in construction. The proposed wall constructed by light expanded clay aggregate in especial shape that reinforced with side plates, top, and bottom rebars. Experimental and numerical studies were carried out to investigate its seismic performance. Experimental results showed a high continuity between blocks of wall due to its especial... 

    A screw dislocation near a damaged arbitrary inhomogeneity–matrix interface

    , Article International Journal of Damage Mechanics ; Volume 29, Issue 2 , 2020 , Pages 272-296 Kamali, M. T ; Shodja, H. M ; Masoudvaziri, N ; Sharif University of Technology
    SAGE Publications Ltd  2020
    In the literature, the analytical solutions concerned with the interaction between screw dislocation and surfaces/interfaces have been mainly limited to simple geometries and perfect interfaces. The focus of the current work is to provide an approach based on a rigorous semi-analytical theory suitable for treatment of such surfaces/interfaces that concurrently have complex geometry and imperfect bonding. The proposed approach captures the singularity of the elastic fields exactly. A vast variety of the pertinent interaction problems such as dislocation near a multi-inhomogeneity with arbitrary geometry bonded imperfectly to a matrix, dislocation near the free boundaries of a finite elastic... 

    Out-of-plane strength reduction of unreinforced masonry walls because of in-plane damages

    , Article Earthquake Engineering and Structural Dynamics ; Volume 44, Issue 13 , 2015 , Pages 2157-2176 ; 00988847 (ISSN) Dolatshahi, K. M ; Yekrangnia, M ; Sharif University of Technology
    John Wiley and Sons Ltd  2015
    There are numerous studies on the behavior of Unreinforced Masonry (URM) walls in both in-plane (IP) and out-of-plane (OP) directions; however, few aimed at understanding the simultaneous contribution of these intrinsic responses during earthquakes. Undoubtedly, even a strong URM wall shows weakened capacity in the OP direction because of minor cracks and other damages in the IP direction, and this capacity reduction has not yet been accounted for in seismic codes. In this study, performance of three URM walls is evaluated by several numerical analyses in terms of the OP capacity reduction because of IP displacements and failure modes. Several parameters influencing the OP capacity have been... 

    A Nonlinear Layerwise Shell Finite Element for Delamination Analysis of Laminated Composite Structures under Large Deformation

    , Ph.D. Dissertation Sharif University of Technology Soltani, Zahra (Author) ; Hosseini Kordkheili, Ali (Supervisor)
    This thesis aims to develop a numerically efficient nonlinear layer-wise shell element formulation for delamination analysis of laminated composite shell structures. The element, in a mesoscale scheme, is formulated based on a zig-zag theory and features three translational degrees of freedom for each node on the mid-surface of the shell in addition with two rotational degrees of freedom for each layer. In this way, the displacement field is formulated via adapting the Mindlin-Reissner theory in each layer and an ordered second-order algorithm for finite rotations. To verify the proposed formulation, many popular benchmark problems for geometric nonlinear analysis of shell problems are... 

    Seismic Performance of Partitions in RC Buildings

    , Ph.D. Dissertation Sharif University of Technology Kazerounian, Alireza (Author) ; Kazemi, Mohammad Taghi (Supervisor)
    Many reinforced concrete frame buildings with masonry partitions have been built all around the world. Observations from past earthquakes show that the partitions can endanger the life of buildings occupants and lead to significant damage and loss. Failure of the partitions can be caused by dynamic vibrations and in-plane and out-of-plane loads/displacements. The interaction between in-plane and out-of-plan behaviors and location of partitions, nonlinearity and higher modes of the structures could affect the out-of- plane seismic demands on partitions. Therefore, there is a need for a comprehensive assessment in order to limit the loss in buildings with masonry partitions. This research... 

    Mechanical properties of double-layered graphene sheets

    , Article Computational Materials Science ; Volume 69 , 2013 , Pages 335-343 ; 09270256 (ISSN) Hosseini Kordkheili, S. A ; Moshrefzadeh Sani, H ; Sharif University of Technology
    In this paper, the molecular structural mechanics method is employed to calculate the mechanical properties of a double-layered carbon graphene sheet more accurately. For this purpose, covalent bonds are modeled using nonlinear beam elements and van der Waals interactions are replaced by nonlinear truss elements. Morse potential and Lennard-Jones potential equations are used to simulate the covalent bonds and van der Waals interactions, respectively. For each atom, van der Waals forces are considered with respect to all the other atoms located in its cut-off radius. In addition to in-plane mechanical properties of single and double-layered graphene sheets some out-of-plane properties like... 

    Out-of-plane stresses in composite shell panels: Layerwise and elasticity solutions

    , Article Acta Mechanica ; Volume 220, Issue 1-4 , 2011 , Pages 15-32 ; 00015970 (ISSN) Miri, A. K ; Nosier, A ; Sharif University of Technology
    Boundary-layer effects in lengthy cross-ply laminated circular cylindrical shell panels under uniform axial extension are investigated by two analytical solutions. First, Reddy's layerwise theory with state-space approach is utilized to determine the local interlaminar stresses. In this method, the general displacement field is discretized through the shell thickness by a linear shape function. When the shell panel is subjected to an axial force, the axial strain is estimated by an equivalent single-layer theory. Second, the stress-function approach along with Fourier series expansion is applied to develop a novel elasticity solution. The elasticity solution, which is based on simply-support... 

    Interaction curves for in-plane and out-of-plane behaviors of unreinforced masonry walls

    , Article Journal of Earthquake Engineering ; Volume 19, Issue 1 , 2015 , Pages 60-84 ; 13632469 (ISSN) Dolatshahi, K. M ; Aref, A. J ; Whittaker, A. S ; Sharif University of Technology
    Taylor and Francis Ltd  2015
    Different types of macro-elements have been proposed to simulate the behavior of unreinforced masonry (URM) structures under seismic loads. In many of these, macro-elements URM walls are replaced with beam elements with different hysteretic behaviors. The effect of out-of-plane loading or change of gravity load due to the overturning moment is usually not considered in the behavior of these macro-elements. This article presents interaction curves for bidirectional loadings of unreinforced masonry walls to investigate the importance of these factors. Two parameters are systematically changed to derive the interaction curves for a wall with specific dimensions, including compressive traction...