Comparative Analysis of Dynamics Characteristics for Static and Operation State of High-speed Spindle System

2012 ◽  
Vol 48 (11) ◽  
pp. 146 ◽  
Author(s):  
Wei SUN
Keyword(s):  
Comparative Analysis ◽  
High Speed ◽  
Spindle System ◽  
Analysis Of Dynamics

scholarly journals Study and Analysis of Anti Vibratory Passive and Active Methods Applied to Complex Mechanical System

2012 ◽  
Vol 7 (2) ◽  
Author(s):  
Cédric Lopez ◽  
François Malburet ◽  
André Barraco
Keyword(s):  
Experimental Study ◽  
Comparative Analysis ◽  
Mechanical System ◽  
High Speed ◽  
Test Bench ◽  
Minimization Method ◽  
Controlled System ◽  
Proper Frequency ◽  
Different Parts ◽  
Methods Of Control

This paper studies problematic of a mechanical system composed of different coupled parts submitted to a high speed shock and proposes analysis of anti vibratory passive and active methods based on an experimental and theoretical coupled approach. After a shock, different parts of the system oscillate. If one of them is excited at a particular frequency, such as its proper frequency, important oscillations appear and can lead to the deterioration of the system by introducing important stresses. In this paper, we propose an analysis in order to understand this kind of problem and what we can do to avoid it. Firstly, we discuss problematic and we expose the studied system. In a second time, we develop two approaches of modeling that allow us to understand the phenomenon by carrying out numerical simulations. Then cross checking of model is completed via experimental study on drop test bench. Passive minimization method of vibrations based on experimental and theoretical coupled approach is exposed. Finally, a comparative analysis of different methods of control and experimental results of controlled system are presented.

scholarly journals COMPARATIVE ANALYSIS OF MODULATION SCHEMES USING ADAPTIVE EQUALIZATION AS FADING MITIGATION TECHNIQUE

2012 ◽  
pp. 25-31
Author(s):  
SABITA NAHATA ◽  
SUBRATA BHATTACHARYA
Keyword(s):  
Comparative Analysis ◽  
Data Transmission ◽  
High Speed ◽  
Signal To Noise Ratio ◽  
Multipath Fading ◽  
Symbol Error Rate ◽  
Adaptive Equalization ◽  
Modulation Scheme ◽  
Modulation Schemes ◽  
Mitigation Technique

Inter-symbol interference (ISI) due to multipath fading is a vital problem in high-speed wireless communication which restricts communication quality and capacity. Therefore, in addition to choosing a fading mitigation technique, it is also important to strategically select a modulation scheme for effective data transmission. Recent literature review on wireless standards, such as 3G and 4G indicates that QAM and QPSK are suitable choices for data transmission. In this paper, a comparative analysis on selected modulation schemes is performed in a fading environment. The mitigation of fading is done using adaptive equalization technique. Also, we show that the signal to noise ratio (SNR) is an important parameter to choose. It is observed that, even when an adaptive equalizer is used at the receiver, a very low SNR gives very high symbol error rate (SER). We derive some important conclusions from our simulation result: QPSK shows minimum SER, whereas 256-PSK and 256-PAM perform worse. Given its spectral efficiency and a low SER, the best choice is 256- QAM.

Design of Hydraulic Motor Spindle for High Speed Machining

2000 ◽  
Author(s):  
Emmanuel I. Agba ◽  
Majid Babai
Keyword(s):  
Composite Materials ◽  
Electric Motor ◽  
High Speed ◽  
Operating Conditions ◽  
High Speed Machining ◽  
Strong Indication ◽  
Hydraulic Motor ◽  
Cutting Power ◽  
Spindle System ◽  
Distinct Increase

Abstract This paper presents the design of a hydraulic motor driven spindle for the processing of metals and composite materials at high rotational speeds. Existing technologies applicable to spindles and spindle holders under severe operating conditions were reviewed. A conceptual design of the hydraulic spindle system was developed. A strong indication of distinct increase in spindle life and gains in cutting power at higher rotational speeds when compared to the conventional electric motor driven spindles underscored the need for the new spindle system.

Resistance Predictions for Asymmetrical Configurations of High-Speed Catamaran Hull Forms

2015 ◽  
Author(s):  
Srikanth Asapana ◽  
Prasanta K. Sahoo ◽  
Vaibhav Aribenchi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Comparative Analysis ◽  
High Speed ◽  
Public Domain ◽  
Literature Survey ◽  
Historical Background ◽  
Resistance Analysis ◽  
Separation Ratio ◽  
Hull Forms

This paper attempts to undertake a comparative analysis of resistance characteristics between newly developed asymmetrical catamaran hull forms which were derived from existing conventional NPL series of round bilge catamaran hull forms by Molland, Wellicome and Couser (1994). A set of asymmetrical catamaran hull forms with waterline length of 1.6 m with a separation ratio (s/L) of 0.4 were generated by using standard modelling software. The resistance analysis had been carried out by using STAR CCM+, a computational fluid dynamics package for Froude numbers of 0.25, 0.30, 0.60, 0.80 and 1.0. Literature survey indicates that there is scant historical background in public domain to perform resistance analysis on asymmetrical catamaran hull forms. As this is not feasible due to lack of data in areas that were considered crucial, separate resistance analysis is carried out for each hull configuration. Finally, the compared resistance results will attempt to conclude whether asymmetrical catamaran hull forms are more efficient than the conventional catamaran hull forms.

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