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    Steel web panel influence on seismic behavior of proposed precast RCS connections

    , Article Structures ; Volume 32 , 2021 , Pages 87-95 ; 23520124 (ISSN) Bakhtiari Doost, R ; Khaloo, A ; Sharif University of Technology
    Elsevier Ltd  2021
    In this study, the experimental finding of two half-scale interior prefabricated Reinforced Concrete column to Steel beam (RCS) sub-assemblage with proposed joint formations with and without web panel in the junction is presented. Previous researches about RCS have been performed to study shear strength of steel web panel in the joint by modeling joint component, however rarely have been conducted to evaluate joint shear resistance experimentally. Over the past 30 years, noticeable analytical and experimental assessments have been performed on the cast in place RCS joints, but seldom have been done on the prefabricated RCS. The steel beams in the proposed joint are attached to the expanded... 

    A novel concept for a deformable joint in offshore structures

    , Article Proceedings of the 21st International Conference on Offshore Mechanics and Arctic Engineering (OMAE), Oslo, 23 June 2002 through 28 June 2002 ; Volume 1 , 2002 , Pages 503-511 Khonsari, S. V ; England, G. L ; Mahboub-Farimani, M. R ; ASME ; Sharif University of Technology
    A new semi-rigid beam-to-column, as well as bracing-to-frame, connection has been developed. In addition to its application in building structures, due to its special features and characteristics, it can best lend itself to offshore jackets, where fracture caused by fatigue has always been a major concern. The adverse effects of welding, material embrittlement, residual stresses, etc., pronounced by cyclic loading on such structures, can be overcome by using this new connection. Moreover, it can be easily used in the structure of various modules used in the topside of platforms and FPSOs. The particular feature of this connection is its geometry, which is so devised that it allows much... 

    Effects of medial thrust gait on lower extremity kinetics in patients with knee osteoarthritis

    , Article Ortopedia, traumatologia, rehabilitacja ; Volume 23, Issue 2 , 2021 , Pages 115-120 ; 20844336 (ISSN) Bokaeian, H. R ; Esfandiarpour, F ; Zahednejad, S ; Kouhzad Mohammadi, H ; Farahmand, F ; Sharif University of Technology
    NLM (Medline)  2021
    BACKGROUND: Medial thrust (MT) gait is a nonsurgical approach for reducing the knee adduction moment (KAM) in patients with knee osteoarthritis. However, its usefulness is indeterminate due to scarcity of research about changes in lower extremity kinetics and the ground reaction force (GRF) which have been investigated in this study. MATERIALS AND METHODS: Twenty patients (6 males, 14 females, age: 56.2±6.2 years) with medial knee osteo-arthritis participated in this cross-sectional study. A 12-camera motion analysis system and two force plates recorded kinematic and GRF data while participants walked barefoot along a 12m path with 1) their regular gait pattern and 2) MT gait pattern. The... 

    Cyclic loading response of simple moment-resisting precast concrete beam-column connection

    , Article ACI Structural Journal ; Volume 100, Issue 4 , 2003 , Pages 440-445 ; 08893241 (ISSN) Khaloo, A. R ; Parastesh, H ; Sharif University of Technology
    In this study, test results of four precast concrete beam-column connections and one monolithic concrete connection are presented. The tests constituted the second phase of an experimental program on a 2/5-scale model precast connection. The objective of the test program was to design a simple moment-resisting precast connection for regions of high seismicity. The connection transfers bending moment by a combination of lap-splicing and end anchorage of bars. The end portions of precast beams sit on the column bearing area at the beginning of subassemblage construction. The variables examined were the level of axial load on column, spacing of beam stirrups in the connection length region,... 

    Comparison of fatigue life for T and cruciform welded joints with different combinations of geometrical parameters

    , Article Engineering Fracture Mechanics ; Volume 67, Issue 4 , 2000 , Pages 313-328 ; 00137944 (ISSN) Motarjemi, A. K ; Kokabi, A. H ; Burdekin, F. M ; Sharif University of Technology
    Elsevier Science Ltd  2000
    The fatigue life for T and cruciform welded joints containing different extents of lack of root penetration was calculated for different combinations of geometrical parameters, including thicknesses up to 45 mm, by integration of the Paris law and use of stress intensity factor solutions calculated previously. The effect of attachment and main plate thickness, weld leg length and initial lack of penetration size on fatigue life was studied. For T welded joints, the effect of different support span has also been investigated. The results are reported as fatigue life curves for both types of joints. All the curves show higher fatigue life for T joints than for cruciform joints. These curves... 

    Dynamic forces at square and inclined rail joints: Field experiments

    , Article Journal of Transportation Engineering ; Volume 142, Issue 9 , 2016 ; 0733947X (ISSN) Ataei, S ; Mohammadzadeh, S ; Miri, A ; Sharif University of Technology
    American Society of Civil Engineers (ASCE)  2016
    Insulated rail joints (IRJs) are widely used in signaling and broken rail identification systems. Track deterioration adjacent to IRJ is frequent due to excessive dynamic forces generated at IRJs by the repetitive passage of the ongoing traffic. Hence, they exhibit low service life and are considered high-risk elements and maintained through high standards. With a view to increase operational speed and the annual operational throughput, many improved structural designs have been proposed, of which inclined IRJs are the focus of this paper. To compare noise, vibration, and adjacent sleepers' vertical displacement of square and 30° and 45° cut joints, a series of field tests have been carried... 

    Innovative structural joint tolerates high rotational and shear overload

    , Article 23rd International Conference on Offshore Mechanics and Arctic Engineering, Vancouver, BC, 20 June 2004 through 25 June 2004 ; Volume 1 B , 2004 , Pages 875-883 Khonsari, S. V ; Parvinnia, S. M. H ; England, G. L ; Hajialiakbari Fini, E ; Sharif University of Technology
    A new beam-to-column and bracing-to-frame connection that can tolerate high rotational and shear overload is described. The connection is a self-contained separate entity that comprises two parallel attachment plates between which two circular tubes are laid and fixed through welding. The whole combination can also be produced by extrusion, where the plates are laid in an orthogonal relation with the axis of bending. In the welded version, the two plates are laid in a parallel relation with the axis of bending  

    Further investigation into a novel concept for a deformable joint in offshore structures

    , Article 22nd International Conference on Offshore Mechanics and Arctic Engineering; Offshore Technology Ocean Space Utilization, Cancun, 8 June 2003 through 13 June 2003 ; Volume 1 , 2003 , Pages 479-487 Khonsari, S. V ; England, G. L ; Parvinnia, S. M. H ; Sharif University of Technology
    A new general semi-rigid beam-to-column connection for skeletal structures, also applicable to offshore platforms, was devised. In a previous paper (OMAE02-28264), the general features of this joint together with some proposed details for its use in fabricating new platforms, as well as retrofitting and repair of existing platforms, were introduced. Moreover, the results of some quasi-static tests on the 'original' version of the connection, in which the energy-dissipating elements (tubes) of the connection are laid in a parallel relation to the axis of bending, were reported. Here, in this paper, the results of recent experimental work on the 'alternate' version of the connection, in which... 

    Dynamic performance of different knee mechanisms with compliant joints

    , Article Scientia Iranica ; Volume 23, Issue 3 , 2016 , Pages 1055-1063 ; 10263098 (ISSN) Ghaemi, N ; Zohoor, H ; Ghaemi, H ; Sharif University of Technology
    Sharif University of Technology  2016
    Loss of lower extremities has been one of the main problems in human life. Although most of the available knee devices are aesthetically acceptable, there is a necessity for lighter and more compact mechanisms, especially for younger amputees. This problem can be solved by the combining compliant mechanism design with traditional mechanism design methods. In this study, one group of the prosthetics that is known as the compliant knee mechanisms" is evaluated. At first, the different knee mechanisms, such as fourand six-bar knee linkages are investigated to calculate the values of the control moments (actuator torque). Then, the suitable location (where the actuator torque is to be exerted)... 

    Effect of reduced graphene oxide reinforcement on creep behavior of adhesively bonded joints

    , Article Mechanika ; Volume 23, Issue 5 , 2017 , Pages 646-652 ; 13921207 (ISSN) Marami, G ; Nazari, S. A ; Faghidian, S. A ; Vakili Tahami, F ; Sharif University of Technology
    Kauno Technologijos Universitetas  2017
    The creep behaviour of adhesively bonded joints is one of the major concerns in modern industry due to their application at relatively high temperature. In this re-search, the effect of added RGO on the creep behaviour of the Araldite 2011 adhesive is investigated. Uni-axial creep tests have been carried out on neat Araldite 2011 and RGO added adhesive at different stress and temperature levels. It has been shown that adhesive with RGO particles demonstrate higher creep resistance. Also, general time hardening models are developed for both materials and their constitutive coefficients have been determined using creep test data. Based on these models, the creep behavior of single lap joints... 

    Kinematic effects of gimbal joints on a 3URU parallel manipulator

    , Article ASME 2012 11th Biennial Conference on Engineering Systems Design and Analysis, ESDA 2012 ; Volume 3 , 2012 , Pages 205-210 ; 9780791844861 (ISBN) Baghi, S ; Razban, F ; Osgouie, K. G ; Sharif University of Technology
    Gimbal transmissions are non-linear direct transmissions and can be used in robotic arms replacing the traditional revolute joints. They offer potential advantages for critical cases such as joint space and task space singularities or where a different mechanical advantage is needed compared to what traditional revolute joints provide. This can be obtained by properly adjusting the different parameters of Gimbal joints used in different joints of the manipulator (such as their offset angle and/or chamfer angle). In this paper the concept of Gimbal mechanism as a joint is investigated. Then, as an example, Gimbal joints are used to replace the basic revolute joints of a 3-UPU parallel... 

    Extending the inverse receptance coupling method for prediction of tool-holder joint dynamics in milling

    , Article Journal of Manufacturing Processes ; Volume 14, Issue 3 , 2012 , Pages 199-207 ; 15266125 (ISSN) Rezaei, M. M ; Movahhedy, M. R ; Moradi, H ; Ahmadian, M. T ; Sharif University of Technology
    Elsevier  2012
    Recently, receptance coupling substructure analysis (RCSA) is used for stability prediction of machine tools through its dynamic response determination. A major challenge is the proper modelling of the substructures joints and determination of their parameters. In this paper, a new approach for predicting tool tip FRF is presented. First, inverse RCSA formulation is extended so that the holder FRFs can be identified directly through experimental modal tests. The great advantage of this formulation is its implementation in arbitrary point numbers along joint length. Therefore, in comparison with previous inverse RCSA approaches, a more realistic joint model can be considered. In addition, due... 

    Manipulability analysis for gimbal driven robotic arms

    , Article 2009 IEEE International Conference on Robotics and Biomimetics, ROBIO 2009, 19 December 2009 through 23 December 2009 ; 2009 , Pages 1039-1044 ; 9781424447756 (ISBN) Mohammadi, F ; Hemmatian, I ; Ghaem Osgouie, K ; Sharif University of Technology
    Gimbal transmissions are non-linear direct transmissions and can be used in robotic arms replacing the traditional revolute joints. To investigate manipulability of robotic manipulators, the classical criterion of Manipulability Ellipsoid has been formulated. Thus by keeping a constant norm for robot joint torques vector, the effects of replacing some traditional revolute joints in robotic arms with Gimbal transmissions, have been analyzed. The results show that the magnitude of the maximum force applicable when employing Gimbal transmission can be considerably larger. Also, the joint angles in which this maximum occurs, can be adjusted, thanks to the behavior of Gimbal transmission. Two... 

    Application of aluminium alloys in a structural joint with great shear deformation capacity

    , Article 25TH International Conference on Offshore Mechanics and Arctic Engineering, OMAE 2006, Hamburg, 4 June 2006 through 9 June 2006 ; Volume 2006 , 2006 ; 0791837777 (ISBN); 9780791837771 (ISBN) Khonsari, S. V ; England, G. L ; Ghahramaninejhad Gharehlar, M ; Sharif University of Technology
    A new structural connection, already discussed in previous papers, with very special and, in some respects, unique, features, such as having very high rotational capacity in bending, and high shear deformation capacity under shear, hence high energy-dissipation capacity under either type of loading, was developed. Specimens of either variant of this joint, fabricated with steel components, were already tested under bending and shear in a mainly separate manner. However, due to the particular shape of the connection, and its ability to be extruded in aluminium, in the most recent work the behaviour of its aluminium specimens under shear loading was studied. A series of specimens fabricated... 

    Phase formation during sintering of nanocrystalline zirconia/stainless steel functionally graded composite layers [electronic resource]

    , Article Journal of Materials Letters ; 15 February 2011, Volume 65, Issue 3, Pages 523–526 Dourandish, M ; Simchi, A. (Abdolreza) ; Hokamoto, K ; Tanaka, S ; Sharif University of Technology
    Microstructural development and phase formation at the interface of yttria stabilized zirconia (3Y-TZP)/430L stainless steel composite layers produced by co-sintering method were studied by SEM, HRTEM, micro-focus XRD, and EPMA. Formation of a rich chromium boundary layer at the interface was noticed, which revealed Cr aggregation at the interface at the elevated temperatures. Misfit dislocations were also observed at the joint interface to tackle the mismatch crystallographic orientations between the ceramic and metal layer. The results of the micro-focus XRD showed formation of no new phases at the boundary zone. Microstructural studies also revealed a retarded grain growth in the... 

    Nonlinear Seismic Assessment of Arch Dams and Investigation of Joint Behavior Using Endurance Time Analysis Method

    , Article Arabian Journal for Science and Engineering ; Vol. 39, issue. 5 , May , 2014 , p. 3599-3615 Hariri-Ardebili, M. A ; Mirzabozorg, H ; Estekanchi, H. E ; Sharif University of Technology
    At the present study, application of endurance time analysis (ETA) method in seismic evaluation of arch dams is investigated. ETA is a time-history based dynamic pushover procedure, which utilizes a set of predesigned intensifying acceleration functions to estimate the responses of the structural systems in various seismic excitation levels. Dez dam was chosen as the case study and all contraction and peripheral joints were modeled based on as-built drawings. The reservoir was modeled as a compressible medium and the foundation was assumed to be massless. Results show that ETA method is able to estimate dynamic responses of the dam with acceptable accuracy in comparison with time history... 

    Geometrical optimization of the overlap in mixed adhesive lap joints

    , Article Journal of Adhesion ; Volume 89, Issue 12 , 2013 , Pages 948-972 ; 00218464 (ISSN) Bavi, O ; Bavi, N ; Shishesaz, M ; Sharif University of Technology
    The aim of this research is to optimize the geometry of the overlap in mixed adhesive single-and double-lap joints using a modified version of Bees and Genetic Algorithms (BA and GA). Accounting for adherends Poisson's ratio in the deduced equilibrium equations, the proposed shear lag model gives a more accurate approximation of joint failure load in comparison with Volkersen's solution. The objective functions used in this work are used separately to maximize the load bearing capacity f and the specific strength (f/w) of the joint. This procedure is applied to optimize aeronautical adhesively bonded assemblies, while taking manufacturing constraints into account. The employed constraints... 

    The seismic performance of new detailing for RCS connections

    , Article Journal of Constructional Steel Research ; Volume 91 , 2013 , Pages 76-88 ; 0143974X (ISSN) Alizadeh, S ; Attari, N. K. A ; Kazemi, M. T ; Sharif University of Technology
    Over the past few decades considerable experimental and numerical studies have been conducted on the Reinforced Concrete columns to Steel beams (RCS) connections. Most of those researches have focused on studying the joint failure modes and ultimate joint strength of specimens utilizing strong beams and columns with weak joints. In this paper, two interior RCS connections were designed based on the Strong Column-Weak Beam (SCWB) criterion. Both specimens were tested under quasi-static reversed cyclic loading. The tested specimens were modeled by a finite element method, which verified with experimental results. Several models with different joint details were investigated using the verified... 

    Fatigue life of repaired welded tubular joints

    , Article International Journal of Engineering, Transactions A: Basics ; Volume 26, Issue 1 , 2013 , Pages 25-31 ; 10252495 (ISSN) Farrahi, G. H ; Majzoobi, G. H ; Mahmoudi, A. H ; Habibi, N ; Sharif University of Technology
    The subject of this study is to investigate the effect of repair on the fatigue life of tubular joints. Six cracked specimens previously subjected to fatigue loading underwent weld repair. Two of these specimens were shot peened before primary fatigue loading. It is shown that repair for the original specimens increases the fatigue life by roughly 150%. The increase of fatigue life for shot peened and repaired specimens is around 105%. The in-depth residual stresses are measured on the repaired joints before and after fatigue loading. It can be stated that repair made a remarkable improvement on the fatigue behavior of tubular joints examined in this investigation. However, where repair is... 

    Failure analysis of brazed air passages of an aircraft fuel system

    , Article Engineering Failure Analysis ; Volume 17, Issue 6 , 2010 , Pages 1495-1499 ; 13506307 (ISSN) Etemadi, A. R ; Behjati, P ; Madaah Hosseini, H. R ; Kokabi, A. H ; Sharif University of Technology