خط مشی دسترسیدرباره ماپشتیبانی آنلاین
ثبت نامثبت نام
راهنماراهنما
فارسی
ورودورود
صفحه اصلیصفحه اصلی
جستجوی مدارک
تمام متن
منابع دیجیتالی
رکورد قبلیرکورد بعدی
Document Type:Latin Dissertation
Language of Document:English
Record Number:53372
Doc. No:TL23326
Call number:‭3378271‬
Main Entry:The Minh Nguyen
Title & Author:A novel semi-active magnetorheological mount for vibration isolationThe Minh Nguyen
College:The University of Toledo
Date:2009
Degree:Ph.D.
student score:2009
Page No:147
Abstract:In recent years, the higher price of fossil fuels and green house effects has been the motivating factors for the automotive industry to introduce more efficient vehicles. Today evolution in automobiles is mostly to reduce fuel consumption and emissions. Variable cylinder management has been employed in V6 & V8 engines to allow the vehicles to operate with only 3 or 4 active cylinders. Hybrid technologies including hybrid electric and emerging hydraulic hybrid equip the vehicles with additional power sources which work at higher efficiency than that of internal combustion engines. The proven advantages of the hybrid vehicles or variable cylinder management also come with challenging problem of noise, vibration and harshness (NVH). This issue has to be properly addressed in order for the technologies to find consumer acceptance. The NVH in modern vehicles is mainly due to the involvement of multiple power sources working in different modes and the switching among them. This feature can lead to shock and vibration over a wide range of frequencies. It has been proven that passive vibration isolators, e.g. elastomeric and hydraulic, are not sufficient to deal with this problem. Active mounts are effective, but they are expensive and can lead to stability problems. Research has shown that semi-active vibration isolators are as effective as active mounts while being significantly less expensive. In this study, a novel shock and vibration isolator in the form of a magnetorheological (MR) mount is introduced. MR fluids are smart fluids which respond to magnetic fields. Using these fluids it is possible to transform a passive hydraulic vibration isolator to a semi-active device one. The semi-active MR mount presented in this dissertation is unique because it utilizes the MR fluid in two configurations flow (or valve) and squeeze modes to mitigate shock and vibration over a wide range of frequencies. The new mount was designed following a thorough literature review of the semi-active and MR vibration isolation. A mathematical model of the mount was developed to represent the vibration isolation behavior of the system. The analytical model was numerically solved and simulated in MATLAB®. Simulation results were used to predict the performance of the mount and to evaluate the effect of design parameters on the mount behavior. A prototype MR mount was built based on the analytical model. The mount was experimentally evaluated. The experimental data was used to verify the model in predicting the mount characteristics. This study provided a fundamental understanding on the behavior of MR fluid in vibration isolation devices. The mount demonstrates effectiveness of the flow and squeeze modes when they are activated individually and in combination. The results of this research can lead to developing effective isolation devices for many different applications including hybrid and alternative fuel vehicles.
Subject:Applied sciences; Vibration isolation; Magnetorheological mount; Noise isolation; Semiactive isolators; Mechanical engineering; 0548:Mechanical engineering
Added Entry:M. H. Elahinia
Added Entry:The University of Toledo