Search for: hydraulic-machinery
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    Application of sensitivity analysis to the development of high performance adaptive hydraulic engine mounts

    , Article Vehicle System Dynamics ; Volume 39, Issue 4 , 2003 , Pages 257-278 ; 00423114 (ISSN) Foumani, M. S ; Khajepour, A ; Durali, M ; Sharif University of Technology
    In this paper, the sensitivity analysis is applied to the development of high performance adaptive hydraulic mounts. The analysis allows us to select the most effective design parameters for tuning an adaptive mount to different road and engine conditions. It is shown that in the low frequency road excitation, the upper chamber compliance and inertia of the fluid column in the inertia track are the most influential properties in changing the dynamic stiffness of the hydraulic mount. These properties for the high frequency engine excitations are the upper compliance and the inertia of the fluid column of the decoupler. For tuning the adaptive mount to different road and engine excitation, a... 

    Design method and feasibility study of fully actively controlled frames

    , Article Scientia Iranica ; Volume 11, Issue 1-2 , 2004 , Pages 50-59 ; 10263098 (ISSN) Joghataie, A ; Asbmarz, M. M ; Sharif University of Technology
    Sharif University of Technology  2004
    In this paper, results of a preliminary study on the feasibility of using an Active Tendon Control (ATC) mechanism for frame structures subject to earthquakes is presented. So far, the ATC mechanism has mainly been considered as a means for installation on structures to mitigate their response under severe loading. In this study, it is desired to evaluate the possibility of using the ATC mechanism to serve as the main means for the stability of frames against earthquakes. Hence, a methodology is presented for the integrated design of frames with ATC mechanisms, which is tested numerically. A number of five-, ten-, fifteen- and twenty-story steel frames are used for this purpose. To this end,... 

    Impact of void ratio and state parameters on the small strain shear modulus of unsaturated soils

    , Article 15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability ; 2015 , Pages 241-246 Khosravi, A ; Gheibi, A ; Rahimi, M ; McCartney, J. S ; Haeri, S. M
    The unsaturated small strain shear modulus, Gmax, is a key reference value in predicting relationships between dynamic shear modulus and shear strain amplitude and is thus a key quantity to properly model the behavior of dynamically-loaded geotechnical systems such as pavements, rail beds, and machine foundations. From the interpretation of the experimental Gmax results for unsaturated soils, different definitions of trends between Gmax and the stress state of the unsaturated soils and material properties are proposed. However, in most of trends, the relationship between the stress state and void ratio is considered and the effect of void ratio on the unsaturated small strain shear modulus... 

    Dynamic simulation of the biped normal and amputee human gait

    , Article Mobile Robotics: Solutions and Challenges - Proceedings of the 12th International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, CLAWAR 2009, 9 September 2009 through 11 September 2009, Istanbul ; 2010 , Pages 1113-1120 ; 9814291269 (ISBN) ; 9789814291262 (ISBN) Shandiz, M. A ; Farahmand, F ; Zohour, H ; Sharif University of Technology
    A two-dimensional seven link biped dynamic model was developed to investigate the mechanical characteristics of the normal and amputee locomotion during the complete gait cycle. The foot-ground contact was simulated using a five-point penetration contact model. The equations of motion were derived using Lagrange method. Optimization of the normal human walking model provided constant coefficients for the driving torque equations that could reasonably reproduce the normal kinematical pattern. The resulting torques were then applied to the intact joints of the amputee model with a prosthetic leg equipped with a kinematical driver controller for the ankle and either a hydraulic, elastic or... 

    Measurement of moisture and temperature profiles in different layers of soil

    , Article 3rd International Foundation Congress and Equipment Expo 2018: Case Histories and Lessons Learned, IFCEE 2018, 5 March 2018 through 10 March 2018 ; Volume 2018-March, Issue GSP 298 , 2018 , Pages 266-278 ; 08950563 (ISSN) Fazel Mojtahedi, F ; Ali, K ; Nazari, A ; Rezvani, S ; Khatami, A ; Ahmadi, N ; Deep Foundations Institute; International Association of Foundation Drilling; Pile Driving Contractors Association; The Geo-Institute (G-I) of the American Society of Civil Engineers (ASCE) ; Sharif University of Technology
    American Society of Civil Engineers (ASCE)  2018
    Over past decades, extensive research has been performed on the measurement of land subsidence as a result of compaction of aquifer. This paper describes results from a new field-monitoring system to evaluate changes in matric suction and temperature profiles in soil layers over an extended time period. The monitoring system used in this study consists of inserting dielectric sensors into a 105 m borehole, drilled in a site in Ardabil Plain, The monitoring results from the site were used to calibrate predictions from HYDRUS-1D. The physical and hydraulic properties of the soil materials in different layers were obtained through performing some soil characteristics and filter paper tests... 

    Economic evaluation of micro-turbines in Iranian electric industry

    , Article 2007 IEEE Lausanne POWERTECH, Lausanne, 1 July 2007 through 5 July 2007 ; 2007 , Pages 1776-1779 ; 9781424421909 (ISBN) Siahkali, H ; Sharif University of Technology
    Today the electric utility industry is being restructured from monopoly and regulated structure to competitive and deregulated structure. Changes in electricity markets, in technology, economics and regulatory structures have created a new interest in small-scale generation and efficiency resources, dispersed throughout the lower voltage networks. Many reasons have been developed and encouraged using DG (Distributed Generation) in different countries such as power system restructuring, DG technologies advances and price increases. The most important problems of many developing countries is the high cost of finance and limited access to financial resources because of the electric industry is... 

    An evolvable self-organizing neuro-fuzzy multilayered classifier with group method data handling and grammar-based bio-inspired supervisors for fault diagnosis of hydraulic systems

    , Article International Journal of Intelligent Computing and Cybernetics ; Vol. 7, issue. 1 , 2014 , p. 38-78 Mozaffari, A ; Fathi, A ; Behzadipour, S ; Sharif University of Technology
    Purpose: The purpose of this paper is to apply a hybrid neuro-fuzzy paradigm called self-organizing neuro-fuzzy multilayered classifier (SONeFMUC) to classify the operating faults of a hydraulic system. The main motivation behind the use of SONeFMUC is to attest the capabilities of neuro-fuzzy classifier for handling the difficulties associated with fault diagnosis of hydraulic circuits. Design/methodology/approach: In the proposed methodology, first, the neuro-fuzzy nodes at each layer of the SONeFMUC are trained separately using two well-known bio-inspired algorithms, i.e. a semi deterministic method with random walks called co-variance matrix adaptation evolutionary strategy (CMA-ES) and... 

    Discharge coefficient of triangular and asymmetric labyrinth side weirs using the nonlinear PLS method

    , Article Journal of Irrigation and Drainage Engineering ; Volume 142, Issue 11 , 2016 ; 07339437 (ISSN) Parvaneh, A ; Kabiri Samani, A ; Nekooie, M. A ; Sharif University of Technology
    American Society of Civil Engineers (ASCE)  2016
    Side weirs are hydraulic control structures widely used in irrigation and drainage systems as well as wastewater treatment plants. These structures also serve as adjusting/diverting flow structures with a minimum head loss. In the present study, by applying experimental data of more than 400 laboratory tests and using the multivariable nonlinear partial least-squares (PLS) method, three nonlinear equations are proposed for discharge coefficient, CM, of triangular and asymmetric labyrinth side weirs. These equations relate the discharge coefficient to the relevant geometrical and hydraulic dimensionless characteristics of flow. Results indicate that the new proposed equations are more... 

    Determination of discharge coefficient of triangular labyrinth side weirs with one and two cycles using the nonlinear PLS method

    , Article Sustainable Hydraulics in the Era of Global Change - Proceedings of the 4th European Congress of the International Association of Hydroenvironment engineering and Research, IAHR 2016, 27 July 2016 through 29 July 2016 ; 2016 , Pages 653-657 ; 9781138029774 (ISBN) Nekooie, M. A ; Parvaneh, A ; Kabiri Samani, A ; Sharif University of Technology
    CRC Press/Balkema  2016
    Side weirs are hydraulic control structures widely used in irrigation, drainage networks and waste water treatment plants. These structures can be used for adjusting and diverting of flow with minimum energy loss. In spite of many studies were carried out on rectangular side weirs, the studies on oblique and labyrinth side weirs are scarce. In this study, based on the experimental data from more than 210 laboratory tests and through using the multivariable nonlinear partial least square (PLS) method, two nonlinear equations are presented for discharge coefficient CM of triangular labyrinth side weirs with one and two cycles. The obtained empirical equations relating CM with the relevant... 

    Consumption criteria and energy labeling of wet cooling towers in Iran

    , Article 2009 ASME Power Conference, 21 July 2009 through 23 July 2009 ; 2009 , Pages 153-157 ; 9780791843505 (ISBN) Sajadi, B ; Sayyadi, P ; Saidi, M. H ; Sharif University of Technology
    Increasing concerns about global warming and environmental pollution control has pushed the relevant organizations to set regulations and to develop programs for energy saving. In addition, for many high energy using appliances, energy labeling provides the end user with important data to select energy-efficient equipments and encourage the manufacturers to enhance the performance of their productions. In this research, a new energy-saving program for wet cooling towers has been developed. Considering a thermo-hydraulic analysis, a novel Energy Index (IE) has been extracted which takes all aspects of the problem into account. The present index can be used as a proper criterion for energy... 

    Design of a mechanically closed-loop test rig for testing aviation industry’s gearboxes

    , Article Aviation ; Volume 21, Issue 4 , 2017 , Pages 132-142 ; 16487788 (ISSN) Mozafari, S ; Rezazadeh Mohamadi, M ; Dolatkhah Takloo, S ; Mardani, M ; Sharif University of Technology
    Due to the wide usage of rotary equipment and the necessity of their testing for maintenance and repair, test rigs have become necessary. The mechanical closed-loop test rig developed in Sharif University of Technology branch of ACECR (Academic Centre of Education, Culture and Research) is a test rig with low energy losses that is suitable for testing high power gearboxes such as aerospace or wind turbine gearboxes. It can be loaded up to 489Hp at a maximum speed of 3000 rpm, and the test components can be tested in different testing conditions including a variety of torques and speeds. This paper describes the preliminary, conceptual, and detailed design, steps including frame work design,... 

    Stabilization of cloud cavitation instabilities using Cylindrical Cavitating-bubble Generators (CCGs)

    , Article International Journal of Multiphase Flow ; Volume 115 , 2019 , Pages 108-125 ; 03019322 (ISSN) Kadivar, E ; el Moctar, O ; Javadi, K ; Sharif University of Technology
    Elsevier Ltd  2019
    Unsteady cloud cavitation phenomenon is an important subject due to its undesirable effects in various applications such as ship propeller, rudder and hydraulic machinery systems. We present an efficient passive control method to control the cavitation instabilities which may be caused by the shedding of cavity structures in the vicinity of the solid surface of an immersible body. We proposed a passive control method so called Cylindrical Cavitating-bubble Generators (CCGs) on the surface of a benchmark hydrofoil and analyzed the effects of this passive controller on the dynamics of the unsteady cloud cavitation. First we modeled the unsteady cavitating flow around the hydrofoil without CCGs... 

    Tuneable vibration absorber design to suppress vibrations: An application in boring manufacturing process

    , Article Journal of Sound and Vibration ; Volume 318, Issue 1-2 , 2008 , Pages 93-108 ; 0022460X (ISSN) Moradi, H ; Bakhtiari Nejad, F ; Movahhedy, M. R ; Sharif University of Technology
    Dynamic vibration absorbers are used to reduce the undesirable vibrations in many applications such as electrical transmission lines, helicopters, gas turbines, engines, bridges, etc. Tuneable vibration absorbers (TVA) are also used as semi-active controllers. In this paper, the application of a TVA for suppression of chatter vibrations in the boring manufacturing process is presented. The boring bar is modeled as a cantilever Euler-Bernoulli beam and the TVA is composed of mass, spring and dashpot elements. In addition, the effect of spring mass is considered in this analysis. After formulation of the problem, the optimum specifications of the absorber such as spring stiffness, absorber...