Loading...
Search for: finite-element-analysis
0.025 seconds
Total 293 records

    Finite element analysis of mechanical performance of nitinol biliary stent: effect of material properties [electronic resource]

    , Article Materials Research Innovations ; Vol 17, No. 2, 2013, 53-59 Nematzadeh, F. (Fardin) ; Sadrnezhaad, K ; Sharif University of Technology
    Abstract
    Stent implantation has been regarded as a major strategy to solve gastrointestinal diseases such as biliary obstruction during the last decade. The application of nitinol superelastic stents has been recently considered for minimising such problems as restenosis after stent implantation, the ability to low stent twist, unsuitable dynamic behaviour and inadequate strength radial of stent. In the present article, the effects of material properties on mechanical performance of Z shaped nitinol wire stent under crushing test for clinical applications are studied by finite element modelling. Nitinol stent shows better mechanical and clinical performance after applying 90% crushing, less chronic... 

    Effects of Crimping on Mechanical Performance of Nitinol Stent Designed for Femoral Artery: Finite Element Analysis [electronic resource]

    , Article Journal of Materials Engineering and Performance ; November 2013, Volume 22, Issue 11, pp 3228-3236 Nematzadeh, F. (Fardin) ; Sadrnezhaad, K ; Sharif University of Technology
    Abstract
    Nitinol stents are used to minimize improper dynamic behavior, low twistability, and inadequate radial mechanical strength of femoral artery stents. In this study, finite element method is used to investigate the effect of crimping and Austenite finish temperature (A f) of Nitinol on mechanical performance of Z-shaped open-cell femoral stent under crimping conditions. Results show that low A f Nitinol has better mechanical and clinical performance due to small chronic outward force, large radial resistive force, and appropriate superelastic behavior  

    Using three-dimensional finite element analysis for simulation of residual stresses in railway wheels

    , Article Engineering Failure Analysis ; Vol. 45, issue , October , 2014 , p. 449-455 Masoudi Nejad, R ; Sharif University of Technology
    Abstract
    One of the most important issues in railway wheels is residual stresses. It is desirable to produce less residual stresses when possible and to decrease the remaining residual stresses in the wheels. The objective of this paper is to provide an estimation of the residual stresses in the rail wheel caused by the stress field from heat treatment process of a railway wheel. A three-dimensional nonlinear stress analysis model has been applied to estimate stress fields of the railway mono-block wheel in heat treatment process. After forging or casting, railway wheels are heat-treated to induce the desirable circumferential compressive residual stress in the upper rim. Finite element analysis... 

    Parameters calculation of transformer winding detailed model based on finite element method to study partial discharge

    , Article International Review on Modelling and Simulations ; Volume 5, Issue 5 , October , 2012 , Pages 1995-2000 ; 19749821 (ISSN) Hosseini, S. M. H ; Vakilian, M ; Enjavimadar, S. M ; Sharif University of Technology
    Praise Worthy Prize  2012
    Abstract
    The first step to locate Partial Discharge in power transformers is to find a model that can clearly explain the behavior of the winding in high-frequency. The detailed model is one of the models used for the study of PD. One of the fundamental problems of the described model is to find its parameters. And the accuracy in calculating these parameters has significant impact on reducing the simulation error and PD locating. The current paper seeks to calculate the parameters of the detailed model 20kv distribution transformer winding by using the finite element method (FEM). Comparing the results of this model with pulse waveforms obtained from the PD to the winding in the laboratory... 

    Comprehensive design of a toroidally-wound limited angle torque motor

    , Article International Review of Electrical Engineering ; Volume 6, Issue 1 , 2011 , Pages 198-206 ; 18276660 (ISSN) Zarandi, R. N ; Kelk, H. M ; Toorani, F ; Farahmandzad, H ; Sharif University of Technology
    Abstract
    This paper presents a comprehensive design procedure of a brushless DC limited angle torque motor (LATM) based on magnetic equivalent circuit analysis which predicts its performance and magnetic characteristics. Design of toroidally wounded armature and rotor with two pole tip segments are developed using selected ferromagnetic material and rare earth permanent magnets. Derivation of airgap and other motor dimensions and design parameters with their expressions are given. A finite element analysis verification of designed LATM using a 2D modeling and simulating package is presented. Performance characteristic of analytical model and FEA model of designed LATM is compared which validates the... 

    Finite element analysis of mechanical performance of nitinol biliary stent: effect of material properties

    , Article Materials Research Innovations ; Volume 17, Issue SUPPL 2 , December , 2013 , Pages S53-S59 ; 14328917 (ISSN) Nematzadeh, F ; Sadrnezhaad, S. K ; Sharif University of Technology
    Abstract
    Stent implantation has been regarded as a major strategy to solve gastrointestinal diseases such as biliary obstruction during the last decade. The application of nitinol superelastic stents has been recently considered for minimising such problems as restenosis after stent implantation, the ability to low stent twist, unsuitable dynamic behaviour and inadequate strength radial of stent. In the present article, the effects of material properties on mechanical performance of Z shaped nitinol wire stent under crushing test for clinical applications are studied by finite element modelling. Nitinol stent shows better mechanical and clinical performance after applying 90% crushing, less chronic... 

    The effect of microthread design on magnitude and distribution of stresses in bone: a three-dimensional finite element analysis

    , Article Dental Research Journal ; Volume 15, Issue 5 , 2018 , Pages 347-353 ; 17353327 (ISSN) Golmohammadi, S ; Eskandari, A ; Movahhedy, M. R ; Shirmohammadi, A ; Amid, R ; Sharif University of Technology
    Abstract
    Background: The researches regarding the influence of microthread design variables on the stress distribution in bone and a biomechanically optimal design for implant neck are limited. The aim of the present study is to compare the effect of different microthread designs on crestal bone stress. Materials and Methods: Six implant models were constructed for three-dimensional finite element analysis including two thread profile (coarse and fine) with three different lengths of microthreaded neck (1 mm, 2 mm, and 3 mm). A load of 200 N was applied in two angulations (0° and 30°) relative to the long axis of the implant and the resultant maximum von Mises equivalent (EQV), compressive, tensile,... 

    Effects of size and shape on elastic constants of graphene sheet

    , Article Structures ; Volume 13 , February , 2018 , Pages 131-138 ; 23520124 (ISSN) Azimi Resketi, N ; Ahmadie Amiri, H ; Dehestani, M ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    Nanotechnology is used in different engineering fields such as mechanical, aerospace, and civil. One of the most interesting structures which recently have come to the center of attention is the Graphene Sheet (GS). Graphene is a material with high potential of usage in civil structures like structural rehabilitation. In the present paper a finite element based structural analysis program is employed to study the mechanical properties of GS. The advantage of using this method is its simplicity and efficiency in different types of loading. The models considered here are based on a structural mechanics approach by using finite beam elements. Variations of Young's moduli of GS versus different... 

    Prediction of flow behavior during warm working

    , Article ISIJ International ; Volume 44, Issue 11 , 2004 , Pages 1867-1873 ; 09151559 (ISSN) Serajzadeh, S ; Sharif University of Technology
    Iron and Steel Institute of Japan  2004
    Abstract
    In this work, the effects of dynamic strain aging and dynamic recovery on metal flow during warm working are studied. Compression experiments are utilized to assess the flow behavior of a low carbon steel under warm deformation conditions. Then, a two dimensional finite element routine is coupled with dynamic recovery and dynamic strain aging models. In this way, the temperature and the velocity fields are predicted during warm working operations with regard to the effects of dynamic recovery and dynamic strain aging. Warm rolling tests are performed in order to verify the modelling results. Comparison between the predicted and measured roll forces shows reliability of the employed model  

    Numerical analysis of metal cutting with chamfered and blunt tools

    , Article Journal of Manufacturing Science and Engineering ; Volume 124, Issue 2 , 2002 , Pages 178-188 ; 10871357 (ISSN) Movahhedy, M. R ; Altintas, Y ; Gadala, M. S ; Sharif University of Technology
    American Society of Mechanical Engineers(ASME)  2002
    Abstract
    In high speed machining of hard materials, tools with chamfered edge and materials resistant to diffusion wear are commonly used. In this paper, the influence of cutting edge geometry on the chip removal process is studied through numerical simulation of cutting with sharp, chamfered or blunt edges and with carbide and CBN tools. The analysis is based on the use of ALE finite element method for continuous chip formation process. Simulations include cutting with tools of different chamfer angles and cutting speeds. The study shows that a region of trapped material zone is formed under the chamfer and acts as the effective cutting edge of the tool, in accordance with experimental observations.... 

    The Effect of Using a Viscoelastic Layer on a Dental Implant on the Stress/Strain Distribution at the Interface of Implant and Jaw Bone

    , M.Sc. Thesis Sharif University of Technology Ghanati, Golsa (Author) ; Ahmadian, Mohammad Taghi (Supervisor) ; Firoozbakhsh, Keikhosrow (Supervisor)
    Abstract
    Natural teeth are connected to alveolar bone by periodontal ligaments ( PDL). PDL in addition to supporting tooth have the damping effect on transferring load from tooth to the surrounding bone. The most common replacement for a complete tooth loss is the use of Osseointegrated dental implants. The healthy bone remodeling and full bonding between bone and titanium surface of the implant is subjected to a successful osseointegration. The lack of PDLs in the structure of implant-bone system could lead to the failure of implant’s components due to overloading or to the impact loads. The aim of this study is to use viscoelastic material in the structure of dental implants to compensate for the... 

    Effects of design parameters and A f temperature on superelastic behaviour of Nitinol stent for application in biliary duct: finite element analysis [electronic resource]

    , Article Materials Technology: Advanced Performance Materials ; Vol. 29, No. 2, 2014, 65-75 Nematzadeh, F. (Fardin) ; Sadrnezhaad, K ; Sharif University of Technology
    Abstract
    For more than a decade, stent implantation has been strategically used for solving gastrointestinal dilemmas such as biliary stenosis. Predicaments like insufficient radial strength, low twisting ability, inappropriate dynamic behaviour and restenosis are expected to be solved by the introduction of new designs. Superelastic Nitinol stent is an interesting alternative for minimising these tight spots. The application of finite element method to predict metallurgical and geometric behaviour of superelastic Nitinol stents for biliary duct dilatation is supported by conventional crimp tests. Model calculations show that all stents encounter the highest stress in their intersegment curvature.... 

    Effect of material properties on the mechanical performance of nitinol esophageal stent: finite element analysis [electronic resource]

    , Article Materials Science Forum ; Volumes 773 - 774, 2014, 9-17 Nematzadeh, F. (Fardin) ; Sadrnezhaad, K ; Kokabi, H. A ; Razani, M ; Mohagheghi, A. H ; Sharif University of Technology
    Abstract
    Stent placement has been a main approach to treat gastrointestinal diseases during past decade. Nitinol superelastic stents have been considered as a solution to such difficulties as restenosis after implantation, low twisting ability, inadequate radial mechanical strength and inappropriate dynamic behaviors associated with the ducts. In this paper, effects of Af temperatures on mechanical performance of z-shaped Nitinol wire stent under crimping test for clinical applications are investigated by finite element simulation. Having 60% crimping and high radial resistive strength, favorable superelastic behaviors are attained at Af temperature of 22°C. The performance of the stent is seen to be... 

    Seepage investigation of embankment dams using numerical modelling of temperature field

    , Article Indian Journal of Science and Technology ; Volume 6, Issue 8 , 2013 , Pages 5078-5082 ; 09746846 (ISSN) Yousefi, S ; Noorzad, A ; Ghaemian, M ; Kharaghani, S ; Sharif University of Technology
    2013
    Abstract
    Leakage in embankment dam by applying seepage and thermal numerical simulations are studied in this paper. Unpredicted seepage in earthen dams is known as the main cause of damage in most cases. Determination of seepage flow quantity and prediction of dam leakage is very important. Temperature variation in dam body can be simulated to estimate the water velocity in soil layers. While moving through dam body, seepage flow carries all physical specifications of reservoir water, including its temperature. Mass and energy balance equations are discretized for modeling flow and temperature fields. The finite element method along with a mathematical model has been utilized to discretize and solve... 

    Effects of the ageing treatment on the superelastic behavior of a nitinol stent for an application in the esophageal duct: A finite-element analysis

    , Article Materiali in Tehnologije ; Volume 47, Issue 4 , 2013 , Pages 453-459 ; 15802949 (ISSN) Nematzadeh, F ; Sadrnezhaad, S. K ; Sharif University of Technology
    2013
    Abstract
    The effects of design parameters and material properties obtained with the ageing treatment on the mechanical performance of a z-shaped esophageal-duct nitinol wire stent under the crushing tests for clinical applications are investigated with a finite-element simulation. With 90 % crushing, low chronic outward force, high radial resistive strength and favorable superelastic behavior are attained at the segment angle of 65° and the Af temperature of 24 °C. The performance of the stent is seen to drastically vary with a change of only 1° in the segment angle  

    Study on optimized piled-raft foundations (PRF) performance with connected and non-connected piles- three case histories

    , Article International Journal of Civil Engineering ; Volume 10, Issue 2 , 2012 , Pages 100-111 ; 17350522 (ISSN) Eslami, A ; Veiskarami, M ; Eslami, M. M ; Sharif University of Technology
    2012
    Abstract
    It has been realized that the raft (mat) foundations are capable of bearing very large loads when they are assisted with a pile group. The contribution of both raft and piles to carry the surcharge loads is taken into account, considering the stiffness and strength of involved elements in the system, i.e. piles, raft and surrounding soil. The piles are usually required not to ensure the overall stability of the foundation but to act as settlement reducers. There is an alternative design in which, the piles are nonconnected from the raft to reduce the settlement, which are then known to be "settlement reducer non-connected piles" to increase the system stiffness. In this paper, two and three... 

    Finite element model of SWCNT under hydrostatic pressure

    , Article AIP Conference Proceedings, 10 April 2007 through 12 April 2007, Sharjah ; Volume 929 , 2007 , Pages 82-88 ; 0094243X (ISSN) ; 0735404399 (ISBN); 9780735404397 (ISBN) Sakhaee Pour, A ; Ahmadian, M. T ; Sharif University of Technology
    2007
    Abstract
    A finite element technique is used to mimic radial deformation of single-walled carbon nanotubes under hydrostatic pressure. The elastic deformation of nanotubes is modeled via elastic beams. Properties of the beam element are evaluated by considering characteristics of the covalent bonds between the carbon atoms in a hexagonal lattice. Applying the beam model in a three dimensional space, the elastic properties of the nanotube in the transverse direction are evaluated. The effects of diameter and wall thickness on the radial and circumferential elastic moduli of zigzag and armchair nanotubes are considered. Results are in good agreement with molecular structural mechanics data in the... 

    Investigating the behavior of circular concrete filled PVC tube columns under concentric and eccentric load using FEM

    , Article Asian Journal of Civil Engineering ; Volume 22, Issue 4 , 2021 , Pages 589-603 ; 15630854 (ISSN) Alinejad, A ; Khaloo, A ; Hassanpour, S ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Abstract
    The purpose of this research is to investigate the response of concrete-filled composite tube column under concentric and eccentric loads. To evaluate the influence of PVC pipe on the behavior of concrete-filled composite tubes, concrete-filled PVC pipe (CFPT) were modeled by ABAQUS software. The results demonstrate that the presence of the PVC pipe makes the concrete column more ductile and have a significant effect on the stress–strain curve of the CFPT after the peak strength, in a way that the confinement increased by raising the thickness of PVC pipe, but the confinement effect of the PVC pipe decreased by the increment of the column diameter and compressive strength of the concrete... 

    Investigating the behavior of circular concrete filled PVC tube columns under concentric and eccentric load using FEM

    , Article Asian Journal of Civil Engineering ; Volume 22, Issue 4 , 2021 , Pages 589-603 ; 15630854 (ISSN) Alinejad, A ; Khaloo, A ; Hassanpour, S ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Abstract
    The purpose of this research is to investigate the response of concrete-filled composite tube column under concentric and eccentric loads. To evaluate the influence of PVC pipe on the behavior of concrete-filled composite tubes, concrete-filled PVC pipe (CFPT) were modeled by ABAQUS software. The results demonstrate that the presence of the PVC pipe makes the concrete column more ductile and have a significant effect on the stress–strain curve of the CFPT after the peak strength, in a way that the confinement increased by raising the thickness of PVC pipe, but the confinement effect of the PVC pipe decreased by the increment of the column diameter and compressive strength of the concrete... 

    Modelling the warm rolling of a low carbon steel

    , Article Materials Science and Engineering A ; Volume 371, Issue 1-2 , 2004 , Pages 318-323 ; 09215093 (ISSN) Serajzadeh, S ; Sharif University of Technology
    2004
    Abstract
    Dynamic strain ageing may occur during warm working of low carbon steels and causes significant changes in flow behaviour and microstructure of the deformed material. Therefore, for a proper designing of an industrial forming process performing under warm deformation conditions, the effect of dynamic strain aging should be taken into account. The aim of this investigation is to predict the velocity and the temperature fields within the rolling metal with regard to the dynamic strain aging. For this purpose, compression tests at various temperatures and strain rates have been conducted to evaluate dynamic strain aging in a low carbon steel. Then, by coupling the experimental results with a...