Search for: brakes
Total 38 records
Article International Polymer Processing ; Volume 21, Issue 4 , 2006 , Pages 421-431 ; 0930777X (ISSN) ; Sharif University of Technology
Carl Hanser Verlag 2006
Composite friction materials used in the braking system of vehicles are composed of different ingredients (typically up to 20 materials). The overall physical properties of these products are determined by the type and percentage of the individual ingredients in the final composition and consequently, may differ from one product to another. This paper studies the cure characteristics of railroad composite brake blocks during compression molding. Numerical simulations using the control volume/finite element method (CV/FEM) are utilized to predict temperature fields and cure conversion during the process. As railroad brake blocks are normally thick-sectioned parts, a three-dimensional modeling...
Article 2006 IEEE International Conference on Mechatronics and Automation, ICMA 2006, Luoyang, 25 June 2006 through 28 June 2006 ; Volume 2006 , 2006 , Pages 1345-1350 ; 1424404665 (ISBN); 9781424404667 (ISBN) ; Fazeli, A ; Valizadeh, M ; Sharif University of Technology
In this paper, a fuzzy based controller is developed in order to control the braking action of the rear axle of a series hybrid city bus. The controller's target is to recapture the kinetic energy of the bus as much as possible during braking, while still maintaining its stability. The bus under study Is one of the Iran-Khodro Company's productions called O457 which is currently undergoing a procedure of hybridization. The hybrid type used is a series hybrid configuration in which an internal combustion engine and a battery pack supply Its electric traction motors in order to propel the bus. The implemented fuzzy controller takes the bus speed, batteries SOC level and the brake-pedal...
Optimization and testing of a new prototype hybrid MR brake with Arc form surface as a prosthetic knee, Article IEEE/ASME Transactions on Mechatronics ; Volume 23, Issue 3 , 2018 , Pages 1204-1214 ; 10834435 (ISSN) ; Sayyaadi, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2018
In this present research work, a new configuration of the hybrid magnetorheological (MR) brake via T-shaped drum with an arc form surface boundary - the biomechanical geometric design of the hybrid MR brake as a prosthetic knee - is discussed and experimentally tested. The main purpose of this study is to develop a prosthetic knee with one rotary disc to fulfill the desired objective. To achieve this, three steps are considered. In the first step, to model the brake, slab method modeling is used to calculate the braking torque due to the arc surface. In the second step, the biomechanical geometric design is adjusted as an optimization problem to maximize the braking torque, minimize the...
A new configuration in a prosthetic knee using of hybrid concept of an MR brake with a T-Shaped drum incorporating an arc form surface, Article Smart Structures and Systems ; Volume 17, Issue 2 , 2016 , Pages 275-296 ; 17381584 (ISSN) ; Zareh, S. H ; Sharif University of Technology
This paper focuses on developing a new configuration on magnetorheological (MR) brake damper as prosthetic knee. Prosthetic knee uses magnetic fields to vary the viscosity of the MR fluid, and thereby its flexion resistance. Exerted transmissibility torque of the knee greatly depends on the magnetic field intensity in the MR fluid. In this study a rotary damper using MR fluid is addressed in which a single rotary disc will act as a brake while MR fluid is activated by magnetic field in different walking gait. The main objective of this study is to investigate a prosthetic knee with one activating rotary disc to accomplish necessary braking torque in walking gait via T-shaped drum with arc...
Effect of alumina nanoparticle on the tribological performance of automotive brake friction materials, Article Journal of Reinforced Plastics and Composites ; Vol. 33, issue. 2 , October , 2014 , pp. 166-178 ; ISSN: 07316844 ; Shojaei, A ; Jahanmard, P ; Sharif University of Technology
Brake friction materials filled with nanoalumina were produced by both conventional and solvent-assisted mixing methods. It was shown that nanoalumina loading led to the reduction of friction coefficient and improvement in mechanical, wear and thermal behaviors. Such behavior was attributed to the role of nanoalumina in producing stable friction layer and easy conduction path in matrix. It was postulated that nanoalumina is able to attach on the surface of microalumina facilitating the rolling of microalumina at interface. Solution-processed samples exhibited lower improvement in tribological and mechanical properties compared to the conventional mixing due to the limited interaction between...
Performance investigation of a four stroke diesel engine, using water-based ferrofluid as an additive, Article ASME 2011 International Mechanical Engineering Congress and Exposition, IMECE 2011, 11 November 2011 through 17 November 2011 ; Volume 4, Issue PARTS A AND B , November , 2011 , Pages 1339-1343 ; 9780791854907 (ISBN) ; Jahani, N ; Shafii, M. B ; ASME ; Sharif University of Technology
In this experimental study, a four stroke diesel engine was conducted to investigate the effect of adding water-based ferrofluid to diesel fuel on engine performance. To our knowledge, Magnetic nanoparticles had not been used before. To this end, emulsified diesel fuels of 0, 0.4, and 0.8 water-based ferrofluid/Diesel ratios by volume were used as fuel. The ferrofluid used in this study was a handmade water-based ferrofluid prepared by the authors. The results show that adding water-based ferrofluid to diesel fuel has a perceptible effect on engine performance, increasing the brake thermal efficiency relatively up to 12%, and decreasing the brake specific fuel consumption relatively up to...
Article 2015 IEEE International Conference on Mechatronics and Automation, ICMA 2015, 2 August 2015 through 5 August 2015 ; Aug , 2015 , Pages 721-726 ; 9781479970964 (ISBN) ; Zareh, S. H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2015
This paper focuses on developing a new configuration on magnetorheological (MR) brake damper as prosthetic knee. Knee uses magnetic fields to vary the viscosity of the MR fluid, and thereby its flexion resistance. Exerted transmissibility torque of the knee greatly depends on the magnetic field intensity in the MR fluid. In this study a rotary damper using MR fluid is addressed in which a single rotary disc will act as a brake while MR fluid is activated by magnetic field in different walking gait. The main objective of this study is to investigate a prosthetic knee with one activating rotary disc to accomplish necessary braking torque in walking gait via implementing of Newton's equation of...
Article Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME ; Volume 125, Issue 1 , 2003 , Pages 48-53 ; 00220434 (ISSN) ; Shadmehri, B ; Sharif University of Technology
A nonlinear comprehensive model has been developed in this paper to study the train derailment and hunting in severe braking conditions. The train consists of cars each having 40 dof, connected to each other by couplers and buffers. The car model is nonlinear and three-dimensional and includes nonlinear springs and dampers of primary and secondary suspensions, dry friction between different parts such as car body and side bearers, center-plate parts, wheelset bearings and bogie frames, and also clearances and mechanical stops. Nonlinearities of wheel and rail profiles, pressure build-up delay in brake circuit, and nonlinearities of connecting parts have also been included in the model. A...
Turbocharged spark-ignition engine performance prediction in various inlet charged air temperatures fueled with gasoline–ethanol blends, Article International Journal of Engine Research ; Volume 22, Issue 7 , 2021 , Pages 2233-2243 ; 14680874 (ISSN) ; Jafari, B ; Kalaki, F ; Sharif University of Technology
SAGE Publications Ltd 2021
In this research, the effect of alternative fuels and the inlet charged air temperature is numerically investigated on the performance of a turbocharged spark-ignition engine. For this purpose, a one-dimensional engine and turbocharger model is created in an engine simulation and performance analysis software and validated with former experimental results. Then, the model is run with four fuel types, including two gasoline types with different octane numbers and two ethanol–gasoline blend fuels—E25 and E85. In each case, the inlet charged air temperature is changed from cold to hot condition and performance characteristics such as the spark advance timing, brake torque, brake-specific fuel...
Study of the Effect of Canopy Lateral Incidence Angle on Autonomous Guidance and Control of Parafoil-Payload System, M.Sc. Thesis Sharif University of Technology ; Saghafi, Fariborz
The trailing edge brakes are the conventional controller mechanisms for autonomous precision delivery parafoil systems. Asymetric braking creates differential drag on the left and right sides of canopy leading to generation of turn rate, whereas symmetric deflection changes the aangle of attack which in turn affects airspeed and limit the glide slope. In the current work , in addition to the conventional controller , the canopy is considered to have the ability of changing its longitudinal and lateral incidence angles. This can be achieved by changing the length of sidelong suspension lines.Unlike brakes, the lateral incidence angle creates heavily coupling in lateral dynamics.The results...
Article Wear ; Volume 274-275 , January , 2012 , Pages 286-297 ; 00431648 (ISSN) ; Shojaei, A ; Sharif University of Technology
Various composite friction materials containing 40. vol.% organic binder (phenolic resin plus styrene-butadiene-rubber (SBR)) with varying phenolic-resin/SBR ratio were prepared. The content of phenolic resin in each composite was indicated by the resin value (RV) index ranging between 0 and 100%. The composites with RVs greater than 50% form resin-based friction materials in which the primary binder is the phenolic resin. For RVs less than 50%, the composites become the rubber-based materials where the primary binder is the SBR. The analysis of mechanical properties exhibited that the conformability of the composites increases upon incorporation of SBR. The frictional analysis revealed that...
Modeling and optimization of friction materials based on genetic programming and experimental frictional data, Article Journal of Reinforced Plastics and Composites ; Volume 34, Issue 7 , 2015 , Pages 581-590 ; 07316844 (ISSN) ; Shojaei, A ; Sharif University of Technology
SAGE Publications Ltd 2015
A genetic programming technique was employed to develop empirical models for predicting specific wear rate and coefficient of friction on brake friction materials. The models consist of independent variables representing the volume fraction of the ingredients. The average absolute relative error for specific wear rate and coefficient of friction were found to be 1.93% and 1.92%, respectively. The models were also verified by the experimental data used for further control of the formulation. Utilizing Tornado plots, the models were found to be able to properly demonstrate the role of the ingredients on overall tribological performance of the brake friction materials. Moreover, a non-dominated...
Effect of short carbon fiber on thermal, mechanical and tribological behavior of phenolic-based brake friction materials, Article Composites Part B: Engineering ; Volume 168 , 2019 , Pages 98-105 ; 13598368 (ISSN) ; Shojaei, A ; Arjmand, M ; Alaei, Y ; Yan, N ; Sharif University of Technology
Elsevier Ltd 2019
The phenolic-based brake friction composites containing 0, 1, 2 and 4 vol% carbon fiber were fabricated in this study. Thermogravimetric analysis (TGA) revealed the adverse impact of carbon fiber on the thermal stability of the composites under air atmosphere. Differential scanning calorimetry (DSC) of the uncured samples indicated the positive impact of carbon fiber on the crosslink density of the phenolic resin. Viscoelastic results drawn from the dynamic-mechanical analysis (DMA) suggested that inclusion of carbon fiber increased the storage modulus and decreased the damping factor of the frictional composites. The tribological behavior of the specimens was assessed with a chase type...
Ph.D. Dissertation Sharif University of Technology ; Durali, Mohammad ; Salarieh, Hassan
In this thesis vehicle path-following in the presence of rollover risk is investigated. Vehicles with high center of mass are prone to roll instability. Untripped rollover risk is increased in high center of gravity vehicles and high-friction road condition. Some researches introduce strategies to handle the short-duration rollover condition. These strategies, however, yield to trajectory tracking error in semi-static maneuvers. Tracking error may also cause tripped rollover. In some other works rollover is prevented by velocity reduction. Rollover is again probable before sufficient reduction of velocity. This thesis puts stress on tracking error from rollover prevention. A lower level...
M.Sc. Thesis Sharif University of Technology ; Behzad , Mehdi ; Hoviattalab, Maryam
The purpose of this project is fault diagnosis of anti-lock brake system with mechatronic approach. To do this, first an appropriate model of the system has been developed. After validating the model, the effects of change in some parameters that indicates the occurrence of a fault in the system are used to examine the behavior of the system in a model-based manner. With this method, it can be analyzed that how a specific fault will impact other system parameters. in fact; the effect of various defects in the system can be detected.
To do this, four common faults such as fault occurrence in hydraulic pump and solenoid valves, air presence and oil leakage in the system are implemented...
To do this, four common faults such as fault occurrence in hydraulic pump and solenoid valves, air presence and oil leakage in the system are implemented...
M.Sc. Thesis Sharif University of Technology ; Behzad, Mahdi
Anti-lock brakes car as one of the most fundamental and vehicle stability control system is considered. Solenoid valves, one-way valves, Accumulator, damper orifices and other components is a crucial role in the anti-lock system performance, so that the performance of the system and thus affect the dynamic performance of the vehicle. This is the most important part of the anti-lock brake System and These components are all new brake system.In this study a complete modeling of hydraulic control unit and obtain sufficient data to model the dynamic behavior of the hydraulic control unit to be seen. operators working in higher frequencies are weak and virtually reached saturation and efficient...
M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar
In the recent decade, composites have been used in safety system of automobiles due to important characteristics such as high wear resistant and durability, low weight and also low noise pollution, stable friction coefficient, availability and low cost. In recent years, composites have attracted the attention of brake pads manufacturers because of their appropriate thermal and mechanical properties. Fibers play an important role in these material. Carbon fiber due to its features such as high strength, acceptable module, proper heat transfer coefficient and excellent resistant against thermal degradation has been considered by the experts but there is not any comprehensive research on...
An Investigation of Alumina Nanoparticles Role on the Performance of Automotive Brake Friction Materials, M.Sc. Thesis Sharif University of Technology ; Shojaei, Akbar
The research on the automotive brake composite materials is very extensive due to its complex formulation and the used of diverse variety of materials. While various research activities has been applied in this research group, but there are many unknown areas. This subject with the arrival of new materials, especially nanometer materials, has received increasing attention. In this study, the effect of alumina nanoparticles on the performance of automotive brake friction materials were examined. Generally, alumina (as micro particles) used as the abrasive material for many years in the formulation of composite brake pads. But, the effect of alumina on the nanometer scale hasn't been examined...
Article 2005 SAE World Congress, Detroit, MI, 11 April 2005 through 14 April 2005 ; 2005 ; 01487191 (ISSN) ; Atharifar, H ; Gholami, M ; Sharif University of Technology
SAE International 2005
In this paper, a tolerance allocation approach is proposed which attempts to select tolerances for individual dimensional variables of a product in a way that minimizes the cost while maintaining critical design requirements. The algorithm uses a reciprocal power cost-tolerance function which incorporates variable sensitivities computed in a DLM-based tolerance analysis technique. The process capabilities are applied as constraints and the genetic algorithm is used to find the optimum solution. The method is applied to a heavy duty brake problem and its results are presented. Copyright © 2005 SAE International
Article DETC2005: ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, Long Beach, CA, 24 September 2005 through 28 September 2005 ; Volume 6 C , 2005 , Pages 2181-2188 ; 0791847438 (ISBN); 9780791847435 (ISBN) ; Jalili, M. M ; Sharif University of Technology
American Society of Mechanical Engineers 2005
The rail-wheel interactions and their effects on the wagon dynamics has been studied in this article. Also the effects of braking on wagon and rail vibrations are studied. The model consists of a wagon with body, two bogies and four wheels having 21 degrees of freedom in a planar arrangement. The rail system is treated as a Timoshenko beam supported by sleepers, ballast, subballast, and subgrade. To determine rail-wheel contact forces, Hertzian nonlinear contact theory and Kalker theory have been used. The model is simulated for a number of working conditions and the results are validated by comparing to previous works in the literature. Copyright © 2005 by ASME