Showing papers by "Satish C. Sharma published in 2009"

Fault diagnosis of a rotor bearing system using response surface method

Abstract: Dynamic analysis of a high-speed rotor bearing systems is challenged by their highly nonlinear and complex properties. Hence, an approximate response surface method (RSM) is utilized to analyze the effects of design and operating parameters on the vibration signature of a rotor-bearing system. This paper focuses on accurate performance prediction, which is essential to the design of high performance rotor bearing system. It considers distributed defects such as internal radial clearance and surface waviness of the bearing components. In the mathematical formulation the contacts between the rolling elements and the races are considered as nonlinear springs, whose stiffnesses are obtained by using Hertzian elastic contact deformation theory. The governing differential equations of motion are obtained by using Lagrange's equations. In terms of the feature that the nonlinear bearing forces act on the system, a reduction method and corresponding integration technique is used to increase the numerical stability and decrease computer time for system analysis. Parameters effects are analyzed together and its influence considered with DOE and Surface Response Methodology are used to predict dynamic response of a rotor-bearing system.

Notice of Violation of IEEE Publication Principles CZM-DSR: A New Cluster/Zone-Disjoint Multi-Path Routing Algorithm For Mobile Ad-Hoc Networks

Abstract: Multi-path routing algorithms in MANETs are an attempt to find node-disjoint to achieve higher fault tolerance. By using node-disjoint paths, it is expected that the end-to-end delay in each case should be independent of each other. In this case some of the intermediate nodes should be silent to reverence their neighbors and this matter increases the end-to-end delay. To avoid this problem, multi-path routing algorithms can use cluster/zone-disjoint paths instead of node-disjoint paths. In this paper we propose a new multi-path routing algorithm that selects cluster/zone-disjoint paths, using omni-directional antenna. The author evaluate algorithm in several different scenarios. The simulation results show that our approach is very effective in decreasing routing overhead and end-to-end delay.

The Dynamic Behaviour of Chiral, Fixed-Free, Single-Walled Carbon Nanotube-Based Nanomechanical Mass Sensors Due to Atomic Vacancies:

Abstract: The dynamic analysis of single-walled carbon nanotubes (SWCNTs) with chiralities has been performed using an atomistic finite element method. SWCNTs with different chiral angles are considered for the resonant frequency analysis. The cantilever carbon nanotube (CNT) is modelled by considering it as a space frame structure similar to three-dimensional beams and point masses. The beam element elastic properties are calculated by considering the mechanical characteristics of covalent bonds between the carbon atoms in the hexagonal lattice. The mass of each beam element is assumed as a point mass at nodes coinciding with carbon atoms. This atomistic simulation approach is used to visualize the effect of defects such as atomic vacancies in the CNT on the resonant frequency. The variation of the atomic vacancy is performed along the length and the response is obtained for different chiralities. It is observed that there is a reduction in the simulated natural frequency due to the atomic vacancy. This has a sign...

Fault Diagnosis of Ball Bearings Using Soft Computing

Abstract: This paper presents the condition monitoring and fault diagnosis of rolling element bearings using Support Vector Machines (SVM). The vibration response of healthy bearings and bearings with various component defects such as outer race, inner race, balls and their combination have been analyzed. From the obtained vibration spectrum, it is clearly seen that a discrete peak of excitation appeared for the specific defect of bearings. In this paper, various faults of the bearings has been simulated and classified. The process includes, data acquisition, feature extraction from time response and a knowledge based system to classify faults. Features defining feature vectors are formed using statistical techniques and are fed as input to the support vector machine (SVM) classifiers. Knowledge based system developed for classification can be used for automatic recognition of machinery faults based on feature vector.Copyright © 2009 by ASME

Analysis of a Worn Multirecess Hydrostatic Journal Bearing System

Abstract: In recent times Hydrostatic journal bearings have received considerable amount of attention by the researchers on account of their excellent performance as compared to other class of bearings. The objective of the present paper is to presents an analysis of a four-pocket capillary-compensated worn hydrostatic journal bearing system. The FEM has been used to solve the Reynolds equation governing the flow of lubricant in the clearance space of a multirecess journal bearing system together with capillary restrictor flow equation as a constant. The bearing performance characteristics of a capillary compensated 4-pocket worn hydrostatic journal bearing have been presented for a wide range of values of external load and nondimensional wear depth parameters. The numerically simulated results of bearing characteristics parameters in terms of maximum fluid-film pressure, minimum fluid-film thickness, lubricant flow rate and fluid film reaction have been presented. The simulated results suggest that for an accurate prediction of bearing characteristics data it is essential to include the effect of wear in the analysis of the hydrostatic journal bearing system.Copyright © 2009 by ASME