Loading...
Search for: abedinnasab--m--h
0.165 seconds

    Exact formulations of non-linear planar and spatial Euler-Bernoulli beams with finite strains

    , Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 226, Issue 5 , 2012 , Pages 1225-1236 ; 09544062 (ISSN) Abedinnasab, M. H ; Zohoor, H ; Yoon, Y. J ; Sharif University of Technology
    2012
    Abstract
    Using Hamilton's principle, exact equations of motion for non-linear planar and spatial Euler-Bernoulli beams are derived. In the existing non-linear Euler-Bernoulli beam formulations, some elastic terms are dropped by differentiation from the incomplete Green-Lagrange strain tensor followed by negligible elastic deformations of cross-sectional frame. On the other hand, in this article, the exact strain field concerning considerable elastic deformations of cross-sectional frame is used as a source in differentiations. As a result, the achieved closed-form equations are exact and more accurate than formerly reported equations in the literature. Moreover, the applicable dynamic model of... 

    Nonlinear analysis of 2D flexible flapping wings

    , Article Nonlinear Dynamics ; Volume 81, Issue 1-2 , July , 2015 , Pages 299-310 ; 0924090X (ISSN) Abedinnasab, M. H ; Zohoor, H ; Yoon, Yong Jin ; Sharif University of Technology
    Kluwer Academic Publishers  2015
    Abstract
    Natural flyers have flexible wings, which deform significantly under the combined inertial and aerodynamic forces. In this study, we focus on the role of chord wise flexibility in 2D pitch and plunge motions. We derive the exact nonlinear 2D equations of motion for a flexible flapping wing with flying support. In achieving the closed-form equations, we use the exact strain field concerning considerable elastic deformations. After numerically solving the novel equations, we validate them in simulations with highly deformable wings. By coupling the derived equations of motion with fluid flow, we study the aerodynamic performance of the geometrically nonlinear flexible flapping wing. Through... 

    Design and analysis of a novel parallel mechanism for prosthetic knee wear test simulators

    , Article Journal of Mechanical Science and Technology ; Volume 31, Issue 2 , 2017 , Pages 885-892 ; 1738494X (ISSN) Daeinejad, F. S ; Farahmand, F ; Durali, M ; Abedinnasab, M. H ; Sharif University of Technology
    Korean Society of Mechanical Engineers  2017
    Abstract
    Using a parallel mechanism in the wear test simulators of prosthetic knees provides an easy access to the femoral and tibial components during tests. Moreover, because of its higher accuracy and load capacity, in comparison with serial mechanisms, it allows simulation of heavier tasks, such as climbing stairs, to be performed. This paper describes a new 3 Degree of freedom (DoF) spatial 2T1R (T: Translational DoF; R: Rotational DoF) parallel mechanism, for reproducing the force and motion of the tibial component of the knee prostheses in a wear test simulator. Kinematics and dynamics analysis of the mechanism indicated that it can satisfy the required DoFs, workspace and load capacity... 

    On the influence of centerline strain on the stability of a bimorph piezo-actuated microbeam

    , Article Scientia Iranica ; Volume 18, Issue 6 , December , 2011 , Pages 1246-1252 ; 10263098 (ISSN) Abedinnasab, M. H ; Kamali Eigoli, A ; Zohoor, H ; Vossoughi, G ; Sharif University of Technology
    2011
    Abstract
    The nonlinear equation of motion for pre-stretched EulerBernoulli beams is derived. The effect of pre-tension and pre-compression in EulerBernoulli beams is studied. It is shown that compressive strain affects the bending stiffness much more than tensile strain. Based on the derived equation, the dynamic model of bimorph piezo-actuated beams, which is accurate, yet simple, is then developed. Afterwards, the critical voltage, which makes the piezo-actuated microbeam unstable, is numerically investigated. It is shown that the strain of the centerline is proportional to the beam's aspect ratio squared. Results show that the more the aspect ratio, the less the critical voltage. In addition, it... 

    Wave dispersion under finite deformation

    , Article Wave Motion ; Volume 50, Issue 3 , April , 2013 , Pages 374-388 ; 01652125 (ISSN) Abedinnasab, M. H ; Hussein, M. I ; Sharif University of Technology
    2013
    Abstract
    We derive exact dispersion relations for axial and flexural elastic wave motion in a rod and a beam under finite deformation. For axial motion we consider a simple rod model, and for flexural motion we employ the Euler-Bernoulli kinematic hypothesis and consider both a conventional transverse motion model and an inextensional planar motion model. The underlying formulation uses the Cauchy stress and the Green-Lagrange strain without omission of higher order terms. For all models, we consider linear constitutive relations in order to isolate the effect of finite motion. The proposed theory, however, is applicable to problems that also exhibit material nonlinearity. For the rod model, we... 

    Analysis of a 6-DOF redundantly actuated 4-legged parallel mechanism

    , Article Nonlinear Dynamics ; Volume 58, Issue 4 , 2009 , Pages 611-622 ; 0924090X (ISSN) Abedinnasab, M. H ; Vossoughi, G. R ; Sharif University of Technology
    2009
    Abstract
    In this paper, we propose a new 4-legged 6-DOF redundantly actuated UPS parallel mechanism. Kinematics, singularity and dynamics analyses of the proposed mechanism are addressed. Inverse kinematics has a closed-form solution, whereas the forward kinematics has a semi-closed form solution. Also, the Jacobian matrix has been determined using the concept of reciprocal screws. Using the principle of virtual work and minimum norm method, a general formulation for the inverse dynamics of redundantly actuated parallel manipulator is presented. Moreover, the proposed redundant mechanism has been compared with a similar but nonredundant mechanism in three aspects: reachable points, and actuation... 

    The wide-open three-legged parallel robot for long-bone fracture reduction

    , Article Journal of Mechanisms and Robotics ; Volume 9, Issue 1 , 2017 ; 19424302 (ISSN) Abedinnasab, M. H ; Farahmand, F ; Gallardo Alvarado, J ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2017
    Abstract
    Robotic reduction of long bones is associated with the need for considerable force and high precision. To balance the accuracy, payload, and workspace, we have designed a new six degrees-offreedom three-legged wide-open robotic system for long-bone fracture reduction. Thanks to the low number of legs and their nonsymmetrical configuration, the mechanism enjoys a unique architecture with a frontally open half-plane. This facilitates positioning the leg inside the mechanism and provides a large workspace for surgical maneuvers, as shown and compared to the well-known Gough-Stewart platform. The experimental tests on a phantom reveal that the mechanism is well capable of applying the desired... 

    High performance fuzzy-Padé controllers: Introduction and comparison to fuzzy controllers

    , Article Nonlinear Dynamics ; Volume 71, Issue 1-2 , January , 2013 , Pages 141-157 ; 0924090X (ISSN) Abedinnasab, M. H ; Yoon, Y. J ; Saeedi Hosseiny, M. S ; Sharif University of Technology
    2013
    Abstract
    In this paper, a new highly convergent, efficient, and fast response control technique entitled as fuzzy-Padé control method is introduced. It provides a simple methodology to exploit the heuristic knowledge in controlling a system. Fuzzy-Padé controllers originate from a unification of heuristic knowledge expressed as the rule base, and Padé approximants. In this method, fuzzy singleton rules are used to generate the rule base. Accordingly, unknown parameters in the Padé approximant are determined using these rules. The fuzzy-Padé controllers possess certain advantages over fuzzy controllers, and they can be applied in situations where fuzzy controllers previously failed. To demonstrate the... 

    Analysis of elastic wave propagation in nonlinear beams

    , Article Proceedings of the ASME Design Engineering Technical Conference ; Volume 1, Issue PARTS A AND B , 2011 , Pages 207-212 ; 9780791854785 (ISBN) Abedinnasab, M. H ; Hussein, M. I ; Des. Eng. Div. Comput. Inf. Eng. Div ; Sharif University of Technology
    2011
    Abstract
    We derive the exact dispersion relations for flexural elastic wave motion in a beam under finite deformation. We employ the Euler-Bernoulli kinematic hypothesis. Focusing on homogeneous waveguides with constant cross-section, we utilize the exact strain tensor and retain all high order terms. The results allow us to quantify the deviation in the dispersion curves when exact large deformation is considered compared to the small strain assumption. We show that incorporation of finite deformation shifts the frequency dispersion curves downwards. Furthermore, the group velocity increases with wavenumber but this trend reverses at high wavenumbers when the wave amplitude is sufficiently high. At... 

    Fuzzy-Pade' Method for Approximating the Aerodynamic Forces in Dynamic Modeling of the Flexible Flapping Wing

    , Ph.D. Dissertation Sharif University of Technology Abedinnasab, Mohammad Hossein (Author) ; Zohoor, Hassan (Supervisor)
    Abstract
    In this thesis, we have derived the exact equations of motion for flexible beams. The derived equations are compared with similar equations reported in the literature, and they demonstrate significant power in prediction of the numerical results. The model for planar beams is verified by the performed experiments on carbon fiber rods. A new highly convergent, efficient technique which is quite fast is also developed for both approximating and controlling a system, entitled as fuzzy-Pade method. We then have studied effects of the wing flexibility on enhancing the lift and trust coefficients in the flapping flight. Aerodynamic force generation due to flapping is simulated for both the... 

    A 3-legged parallel robot for long bone fracture alignment

    , Article ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC/CIE 2017, 6 August 2017 through 9 August 2017 ; Volume 3 , 2017 ; 9780791858158 (ISBN) Abedinnasab, M. H ; Farahmand, F ; Gallardo Alvarado, J ; Computers and Information in Engineering Division; Design Engineering Division ; Sharif University of Technology
    American Society of Mechanical Engineers (ASME)  2017
    Abstract
    The reduction of long bone fractures is traditionally an invasive procedure with drawbacks of intense force, soft tissue damage, and, both, rotational and longitudinal malalignment. To combat these drawbacks, we applied a novel, wide open, threelegged, 6-DOF parallel robot, to the current surgical procedure. This platform will balance the accuracy, payload, and workspace for the surgeon, resulting in more efficient, successful surgeries. The experimental tests on a phantom reveal that the mechanism is well capable of applying the desired reduction steps against the large muscular payloads with high accuracy. © 2017 ASME  

    Optimal MIMO waveform design with controlled characteristics

    , Article Proceedings International Radar Symposium, 24 June 2015 through 26 June 2015 ; Volume 2015-August , 2015 , Pages 1141-1146 ; 21555753 (ISSN) ; 9783954048533 (ISBN); 9783954048533 (ISBN); 9783954048533 (ISBN) Karbasi, S. M ; Radmard, M ; Nayebi, M. M ; Bastani, M. H ; Rohling, H ; Rohling, H ; Rohling, H ; Sharif University of Technology
    IEEE Computer Society  2015
    Abstract
    In a MIMO (Multiple Input Multiple Output) radar system, proper design of transmit signal and receive filter is an advantageous tool to improve the detection performance. Thus, in this paper, we consider the problem of transmit code and receive filter design, in order to maximize the Signal to Noise Ratio (SNR) at the receiver while enforcing a similarity constraint between the transmit space-time code (STC) and a reference STC which has a desirable ambiguity function. We will show that by solving such constrained optimization problem through successive iterations, our proposed method leads to satisfactory results  

    A fast and novel method of pattern synthesis for non-uniform phased array antennas

    , Article Proceedings International Radar Symposium, 24 June 2015 through 26 June 2015 ; Volume 2015-August , 2015 , Pages 924-929 ; 21555753 (ISSN) ; 9783954048533 (ISBN); 9783954048533 (ISBN); 9783954048533 (ISBN) Tohidi, E ; Sebt, M. A ; Nayebi, M. M ; Behroozi, H ; Rohling, H ; Rohling, H ; Rohling, H ; Sharif University of Technology
    IEEE Computer Society  2015
    Abstract
    Weighting elements to achieve radiation patterns with desired characteristics is a classical work in phased array antennas. These characteristics can be low sidelobe level, narrow beamwidth, high directivity, pattern nulling in special angle and etc. For each of these characteristics, different methods have been introduced. Most of methods have been presented for uniform arrays, however there are lots of methods to obtain a desired pattern for antennas with non-uniform element distances. The problem with these methods is complexity or not very good results. In this paper, fast and easy methods based on Least Square Error that leads to good results are presented. In addition, weighting of... 

    Sustainable solutions for advanced energy management system of campus microgrids: model opportunities and future challenges

    , Article Sensors ; Volume 22, Issue 6 , 2022 ; 14248220 (ISSN) Muqeet, H. A ; Javed, H ; Akhter, M. N ; Shahzad, M ; Munir, H. M ; Nadeem, M. U ; Bukhari, S. S. H ; Huba, M ; Sharif University of Technology
    MDPI  2022
    Abstract
    Distributed generation connected with AC, DC, or hybrid loads and energy storage systems is known as a microgrid. Campus microgrids are an important load type. A university campus microgrids, usually, contains distributed generation resources, energy storage, and electric vehicles. The main aim of the microgrid is to provide sustainable, economical energy, and a reliable system. The advanced energy management system (AEMS) provides a smooth energy flow to the microgrid. Over the last few years, many studies were carried out to review various aspects such as energy sustainability, demand response strategies, control systems, energy management systems with different types of optimization... 

    Atomistic insight into salinity dependent preferential binding of polar aromatics to calcite/brine interface: implications to low salinity waterflooding

    , Article Scientific Reports ; Volume 11, Issue 1 , 2021 ; 20452322 (ISSN) Koleini, M. M ; Badizad, M. H ; Mahani, H ; Dastjerdi, A. M ; Ayatollahi, S ; Ghazanfari, M. H ; Sharif University of Technology
    Nature Research  2021
    Abstract
    This paper resolve the salinity-dependent interactions of polar components of crude oil at calcite-brine interface in atomic resolution. Molecular dynamics simulations carried out on the present study showed that ordered water monolayers develop immediate to a calcite substrate in contact with a saline solution. Carboxylic compounds, herein represented by benzoic acid (BA), penetrate into those hydration layers and directly linking to the calcite surface. Through a mechanism termed screening effect, development of hydrogen bonding between –COOH functional groups of BA and carbonate groups is inhibited by formation of a positively-charged Na+ layer over CaCO3 surface. Contrary to the common... 

    MIMO ambiguity function optimization through waveform design

    , Article Proceedings International Radar Symposium, 24 June 2015 through 26 June 2015 ; Volume 2015-August , 2015 , Pages 333-338 ; 21555753 (ISSN) ; 9783954048533 (ISBN); 9783954048533 (ISBN); 9783954048533 (ISBN) Radmard, M ; Majd, M. N ; Chitgarha, M. M ; Karbasi, S. M ; Nayebi, M. M ; Rohling, H ; Rohling, H ; Rohling, H ; Sharif University of Technology
    IEEE Computer Society  2015
    Abstract
    An important tool for assessing a radar's performance is the ambiguity function. On the other hand, many different schemes have been designed for the transmit waveforms of a MIMO radar. For each one, a criterion has been chosen to improve the performace, e.g. achieving better missed detection. In this paper, considering the ambiguity function as the benchmark, we propose a waveform design scheme, which optimizes the ambiguity function of the MIMO radar system  

    Laminar falling film flow of aqueous Li Br solution on a horizontal elliptical tube

    , Article International Journal of Fluid Mechanics Research ; Volume 40, Issue 4 , 2013 , Pages 324-343 ; 10642277 (ISSN) Abyaneh, M. H. J ; Saidi, M. H ; Sharif University of Technology
    2013
    Abstract
    Flow hydrodynamics of laminar falling film of aqueous Li Br solution (Li Br - H2O) on a horizontal elliptical tube has been investigated in this research. The film velocity distribution and film thickness, namely, the flow characteristics are determined by solving analytically simultaneous simplified Navier - Stokes equations and continuity equation in polar and Cartesian coordinates. The analysis is based on steady state laminar flow of falling liquid film of Li Br - H2O on a horizontal elliptical tube in polar model and Cartesian model (CM), for cases in which traction on the film surface is considered negligible. Models are compared with each other in three cases of aspect ratios (Ar),... 

    Velocity distributions in (r,θ) directions for laminar flow of a film around horizontal circular tube

    , Article 2006 ASME Joint U.S.- European Fluids Engineering Division Summer Meeting, FEDSM2006, Miami, FL, 17 July 2006 through 20 July 2006 ; Volume 1 SYMPOSIA , 2006 , Pages 11-19 ; 0791847500 (ISBN); 9780791847503 (ISBN) Abyaneh, M. H. J ; Saidi, M. H ; Sharif University of Technology
    American Society of Mechanical Engineers  2006
    Abstract
    Velocity distributions in (r,θ) directions are evaluated by solving simultaneous simplified Navier-Stokes equations (NSE) and continuity equation (CE) in polar coordinate. The analysis is based on steady state laminar flow of thin falling liquid film on a horizontal circular tube, for cases in which traction on the film surface is considered negligible. It is a common geometry for part of engineering problems such as evaporator, condenser, absorber, generator of absorption chillers and other similar units in mechanical and chemical engineering. Knowledge of the velocity profiles is usually needed for: 1 - solving governing energy and species equations 2- estimating the average and film... 

    Velocity distributions in (r,θ) directions for laminar flow of a film around horizontal circular tube

    , Article 2006 2nd ASME Joint U.S.-European Fluids Engineering Summer Meeting, FEDSM 2006, Miami, FL, 17 July 2006 through 20 July 2006 ; Volume 2006 , 2006 ; 0791837831 (ISBN); 9780791837832 (ISBN) Abyaneh, M. H. J ; Saidi, M. H ; Sharif University of Technology
    2006
    Abstract
    Velocity distributions in (r,θ) directions are evaluated by solving simultaneous simplified Navier-Stokes equations (NSE) and continuity equation (CE) in polar coordinate. The analysis is based on steady state laminar flow of thin falling liquid film on a horizontal circular tube, for cases in which traction on the film surface is considered negligible. It is a common geometry for part of engineering problems such as evaporator, condenser, absorber, generator of absorption chillers and other similar units in mechanical and chemical engineering. Knowledge of the velocity profiles is usually needed for: 1- solving governing energy and species equations 2- estimating the average and film... 

    An experimental investigation of foam for gas mobility control in a low-temperature fractured carbonate reservoir

    , Article Petroleum Science and Technology ; Volume 30, Issue 10 , 2012 , Pages 976-985 ; 10916466 (ISSN) Gandomkar, A ; Kharrat, R ; Motealleh, M ; Khanamiri, H. H ; Nematzadeh, M ; Ghazanfari, M. H ; Sharif University of Technology
    2012
    Abstract
    This work concerns the experimental investigation of surfactant alternating CO 2 injection in carbonate rocks. The core samples provided from a low-temperature fractured light oil reservoir, located in southwest Iran. The experiments were designed to observe the effect of CO 2-foam injection on gas mobility and oil recovery at different surfactant concentrations. The core samples were initially saturated with synthetic/field brine, 5,000 ppm, and then flooded with live oil to reach connate water saturation at reservoir condition, 115F and 1,700 psia. The commercial surfactant used was sodium lauryl sulfate as an anionic surfactant. The results of this work, along with field-scale simulation...