A Harmonic Wavelets Approach for Extracting Transient Patterns From Measured Rotor Vibration Data

2001 ◽  
Author(s):  
Valeta Carol Chancey ◽  
George T. Flowers ◽  
Candice L. Howard
Keyword(s):  
Vibration Analysis ◽  
Transient Effects ◽  
Rotor Vibration ◽  
Harmonic Wavelets ◽  
Vibration Data ◽  
Harmonic Wavelet ◽  
Vibration Signature ◽  
The Fourier Transform ◽  
Traditional Approaches

Vibration analysis is a powerful diagnostic tool for rotating machinery problems. Traditional approaches to vibration signature analysis have focused on the Fourier transform, which tends to average out transient effects. Recent work in the area of wavelets has allowed for the characterization of signals in frequency and in time, which, if properly interpreted, can provide substantial insight, particularly with regard to transient behaviors. There are many different wavelets, but the harmonic wavelet was developed specifically for vibration analysis. It uses an algorithm based upon the FFT, which makes it particularly attractive to many in the vibration analysis community. This paper considers the harmonic wavelet as a tool for extracting transient patterns from measured vibration data. A method for characterizing transient behaviors using the harmonic wavelet is described and illustrated using simulation and experimental results.

A Harmonic Wavelets Approach for Extracting Transient Patterns From Measured Rotor Vibration Data

2002 ◽  
Vol 125 (1) ◽  
pp. 81-89 ◽  
Author(s):  
V. C. Chancey ◽  
G. T. Flowers ◽  
C. L. Howard
Keyword(s):  
Fourier Transform ◽  
Vibration Analysis ◽  
Transient Effects ◽  
Harmonic Wavelets ◽  
Vibration Data ◽  
Harmonic Wavelet ◽  
Vibration Signature ◽  
The Fourier Transform ◽  
Traditional Approaches

Vibration analysis is a powerful diagnostic tool for rotating machinery problems. Traditional approaches to vibration signature analysis have focused on the Fourier transform, which tends to average out transient effects. Recent work in the area of wavelets has allowed for the characterization of signals in frequency and in time, which, if properly interpreted, can provide substantial insight, particularly with regard to transient behaviors. There are many different types of wavelets, but the harmonic wavelet was developed specifically for vibration analysis. It uses an algorithm based upon the fast Fourier transform (FFT), which makes it particularly attractive to many in the vibration analysis community. This paper considers the harmonic wavelet as a tool for extracting transient patterns from measured vibration data. A method for characterizing transient behaviors using the harmonic wavelet is described and illustrated with simulation and experimental results.

Characterization of Transient Effects in Rotordynamic Vibrations Using Harmonic Wavelets

1999 ◽  
Author(s):  
Valeta Carol Chancey ◽  
George T. Flowers
Keyword(s):  
Steady State ◽  
Journal Bearing ◽  
Wavelet Coefficients ◽  
Transient Effects ◽  
State Behavior ◽  
Absolute Value ◽  
Harmonic Wavelets ◽  
Oil Whirl ◽  
Harmonic Wavelet

Abstract Traditional vibration analysis methods for rotating machinery consider steady state or near steady state behavior. Perhaps a key to identifying the source of some complex behaviors may be the transients associated with such phenomena. In an effort to develop a means of identifying transients, the application of harmonic wavelets is explored. Simple vibratory models were studied using harmonic wavelet analysis. Several general observations were made with characteristics found in the harmonic wavelet coefficients associated with particular behavior. Specifically, a relationship with transient growth and the absolute value of the harmonic wavelet coefficients was identified. Example experimental data was collected and analyzed from a bench top test rig with a journal bearing exhibiting oil whirl to illustrate the proposed methods.

Magnetic Bearing Rotor Vibration Analysis Based on the Harmonic Wavelet Package Algorithm

2012 ◽  
Vol 588-589 ◽  
pp. 152-155
Author(s):  
De Guang Li ◽  
Shu Qin Liu
Keyword(s):  
Frequency Domain ◽  
Vibration Analysis ◽  
Vibration Signal ◽  
Magnetic Bearing ◽  
Rotor Vibration ◽  
Time Frequency ◽  
Optimizing Design ◽  
Harmonic Wavelet ◽  
Frequency Map

Analysis of the magnetic bearing rotor vibration is the base of the optimizing design, supervise and diagnosis of the magnetic bearing. Harmonic wavelet package was used for the analysis of the vibration signal, and the 3 dimension time-frequency domain energy map was constructed, then the analysis of the rotor vibration became convenient. Via analysis of the time-frequency map, the vibration in each time and each frequency was obtained, and the supervise and the diagnosis of the rotor can be realized.

scholarly journals Application of Time-Frequency Analysis to Transient Data from Centrifuge Earthquake Testing

2000 ◽  
Vol 7 (4) ◽  
pp. 195-202 ◽  
Author(s):  
David E. Newland ◽  
Gary D. Butler
Keyword(s):  
Frequency Analysis ◽  
Good Method ◽  
Centrifuge Modeling ◽  
Transient Vibration ◽  
Time Frequency Analysis ◽  
Harmonic Wavelets ◽  
Time Frequency ◽  
Vibration Data ◽  
Harmonic Wavelet ◽  
Detailed Interpretation

Centrifuge model experiments have generated complex transient vibration data. New algorithms for time-frequency analysis using harmonic wavelets provide a good method of analyzing these data. We describe how the experimental data have been collected and show typical time-frequency maps obtained by the harmonic wavelet algorithm. Some preliminary comments on the interpretation of these maps are given in terms of the physics of the underlying model. Important features of the motion that are not otherwise apparent emerge from the analysis. Later papers will deal with their more detailed interpretation and their implications for centrifuge modeling.

Preparation and Characterization of a Novel Mixed Functional Cationic Exchange Copolymer Microsphere as Drug Carrier

2012 ◽  
Vol 476-478 ◽  
pp. 2288-2291 ◽  
Author(s):  
Kaewnapa Wongsermsin ◽  
Praneet Opanasopit ◽  
Tanasait Ngawhirunpat ◽  
Prasert Akkaramongkolporn
Keyword(s):  
Drug Carrier ◽  
Gastric Ph ◽  
The Novel ◽  
Electron Micrograph ◽  
Scanning Electron Micrograph ◽  
Cationic Exchange ◽  
The Fourier Transform ◽  
Release Characteristic ◽  
Dextromethorphan Hydrobromide

The objective of the present study was to prepare a novel mixed functional cationic exchange copolymer microsphere containing methyl methacrylic acid and sulfonated styrene crosslinked with divinylbenzene. The emulsion polymerization was used to prepare the cationic exchange copolymer microsphere which was characterized by the scanning electron micrograph (SEM) and the fourier transform infrared spectroscopy (FTIR). The release characteristic of the loaded drug i.e. dextromethorphan hydrobromide from the copolymer microsphere was studied under both simulated gastric (pH 1.2) and intestinal (pH 6.8) conditions. The result showed that the drug released from the novel copolymer microsphere depended on the pH of the release media.

scholarly journals SURFACE CHEMICAL AND COLOR CHARACTERIZATION OF JUVENILE TECTONA GRANDIS WOOD SUBJECTED TO STEAM-DRYING TREATMENTS

2016 ◽  
Vol 23 (01) ◽  
pp. 1550091 ◽  
Author(s):  
ALEXANDER BERROCAL ◽  
RÓGER MOYA ◽  
MARÍA RODRIGUEZ-SOLIS ◽  
RICARDO STARBIRD ◽  
FREDDY MUÑOZ
Keyword(s):  
Color Change ◽  
Tectona Grandis ◽  
Surface Chemical ◽  
Surface Color ◽  
Teak Wood ◽  
Text Color ◽  
The Fourier Transform ◽  
Moisture Conditions ◽  
Steam Drying

The color of Tectona grandis wood is an attribute that favors its commercialization, however, wood color from fast-growth plantation trees is clear and lacks uniformity. The aim of this work is to characterize steamed teak wood by means of the Fourier transform infrared spectroscopy (FTIR) and [Formula: see text] color systems. Two moisture conditions (green and 50%) and two grain patterns (flat and quarter) of boards were analyzed through the application of different steaming times (0, 3, 6, 9, 12, 15 and 18[Formula: see text]h). The FTIR results showed that the bands at 1158, 1231, 1373 and 1419[Formula: see text]cm[Formula: see text] did not show any change with steaming, whereas the bands at 1053, 1108, 1453, 1506, 1536, 1558, 1595, 1652, 1683, 1700 and 1733[Formula: see text]cm[Formula: see text] presented a decrease in the intensity with the steaming time. The band at 1318[Formula: see text]cm[Formula: see text] was the only one that increased. Lightness ([Formula: see text]) was the most affected parameter, followed by yellowness ([Formula: see text]), while redness ([Formula: see text]) showed the smallest change. Surface color change ([Formula: see text]) presented the lowest value between 3[Formula: see text]h and 6[Formula: see text]h of steam-drying in the boards with flat grain, whereas for boards with quarter grain, the smallest [Formula: see text] value was obtained after 18[Formula: see text]h of steaming.

scholarly journals Nonlinear Vibration Analysis of Rotor considering Cogging and Harmonic Effects

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Shanle Li ◽  
Feng Liu ◽  
Hongyan Wang ◽  
Haijun Song ◽  
Kuilong Yu
Keyword(s):  
Nonlinear Vibration ◽  
Vibration Analysis ◽  
Magnetic Force ◽  
Rotor System ◽  
Kutta Method ◽  
Rotor Vibration ◽  
Motion Equations ◽  
Runge Kutta Method ◽  
Static Eccentricity ◽  
New Formula

This paper aims to investigate nonlinear vibration characteristics of rotor system considering cogging and harmonic effects. Firstly, relative permeance with eccentric was established and then corrected by correction factor caused by the cogging effect. Based on the new formula of relative permeance, the expression of unbalanced magnetic force was obtained, and the coefficient of cogging effect was defined. Motion equations of rotor system were established, and Runge–Kutta method was used to solve the equations. Results showed that errors between finite and analytical results were smaller considering cogging and harmonic effects. When the harmonics were taken into consideration, the vibration of rotor increases sharply. When the cogging and harmonics were taken into consideration simultaneously, the vibration of rotor decreased instead, which means that stator slots have the effect of reducing vibration in rotor system. Rotor vibration was axis symmetry with static eccentricity rather than central symmetry with no eccentricity, and double, four times, and six times supply frequency always existed in the components of main frequency with eccentric.

Wavelet Analysis of Vibration: Part 2—Wavelet Maps

1994 ◽  
Vol 116 (4) ◽  
pp. 417-425 ◽  
Author(s):  
D. E. Newland
Keyword(s):  
Wavelet Analysis ◽  
Vibration Analysis ◽  
Vibration Signal ◽  
Wavelet Method ◽  
Harmonic Wavelets

Wavelet maps provide a graphical picture of the frequency composition of a vibration signal. This paper, which is Part 2 of a pair, describes their construction and properties. In the case of harmonic wavelets, there are close similarities between wavelet maps and sonograms. A range of practical examples illustrate how the wavelet method may be applied to vibration analysis and some of its advantages.

scholarly journals NOVEL APPROACH OF EXTRACTION AND CHARACTERIZATION OF OKRA GUM AS A BINDER FOR TABLET FORMULATION

2019 ◽  
Vol 12 (1) ◽  
pp. 189
Author(s):  
Shayeri Chatterjee ◽  
Rana Mazumder
Keyword(s):  
Hydroxypropyl Methylcellulose ◽  
Scanning Calorimetry ◽  
Swelling Properties ◽  
Novel Approach ◽  
Coated Tablet ◽  
Present Aspect ◽  
Tablet Formulations ◽  
Okra Gum ◽  
The Fourier Transform

Objective: The major objective of the present investigation was to extract a natural polymer (okra gum) with its characterization as pharmaceutical binder and to formulate, develop, and evaluate the compression-coated tablet using okra as binder along with synthetic hydrophilic polymers like various grades of hydroxypropyl methylcellulose (HPMC).Methods: A novel extraction method was carried out using fresh unripe pods of okra (ladies finger) with the aid of organic solvents and its characterization was done. The core tablets were prepared by direct compression method which was compression coated with okra gum and HPMC.Results: After the extraction of the okra gum was carried out, the yield of mucilage obtained was 10%. It is considered as a proof for the purity of the mucilage extract. The above study reveals that the polymers were subjected to the Fourier transform infrared and differential scanning calorimetry thermogram had no significant interactions between the drug and the polymers. The characterization of the new polymer okra showed that it has swelling properties, and in spite of being a hydrophilic polymer, it can be successfully used in pharmaceutical formulation as a good binder.Conclusion: In the present aspect of the study was to evaluate the efficacy of okra gum that has been used as a tablet binder. It is easily available and inexpensive. Okra gum as a binder produces tablet formulations with good physicochemical properties and good candidate for sustained release formulations.

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