Application of the reassignment time–frequency method on an acoustic signals backscattered by an air-filled circular cylindrical shell immersed in water

2013 ◽  
Vol 27 (1) ◽  
pp. 216-224 ◽  
Author(s):  
M. Laaboubi ◽  
E. Aassif ◽  
R. Latif ◽  
A. Dliou ◽  
G. Maze ◽  
...  
Keyword(s):  
Cylindrical Shell ◽  
Circular Cylindrical Shell ◽  
Acoustic Signals ◽  
Frequency Method ◽  
Time Frequency

Analysis of Acoustic Wave Due to Gas Leakage in Buried Gas Pipe

2009 ◽  
Author(s):  
Eui Youl Kim ◽  
Min Soo Kim ◽  
Sang Kwon Lee
Keyword(s):  
Wave Propagation ◽  
Acoustic Wave ◽  
Low Frequency ◽  
Acoustic Signals ◽  
Frequency Method ◽  
Theoretical Formulation ◽  
Steel Pipes ◽  
Time Frequency ◽  
Gas Leakage ◽  
Made In

A time frequency technique for locating leaks in buried gas distribution pipes involves the use of the cross-correlation on two measured acoustic signals on either side of a leak. This technique can be problematic for locating leaks in steel pipes, as the acoustic signals in these pipes are generally narrowband and low frequency. The effectiveness of the time-frequency technique for detecting leaks in steel pipes was investigated experimentally in an earlier study. The object of this paper is to identify the characteristics of this dispersive acoustic wave through analysis of the cut-off frequency by using the time-frequency method experimentally and BEM (boundary element method) theoretically for the development of an experimental tool to analyze the leak signals in steel pipe. The tool is based on experimental work and theoretical formulation of wave propagation in a fluid-filled pipe. This tool uses the time-frequency method to explain some of the features of wave propagation measurements made in gas pipes. Leak noise signals are generally passed through a time-frequency filter for detection of impulse signal related leakage.

Fuzzified time-frequency method for identification and localization of power system faults

2021 ◽  
pp. 1-13
Author(s):  
Pullabhatla Srikanth ◽  
Chiranjib Koley
Keyword(s):  
Power System ◽  
High Accuracy ◽  
Fuzzy Decision ◽  
Frequency Method ◽  
Time Frequency ◽  
Novel Approach ◽  
S Transform ◽  
Different Types ◽  
Power System Faults ◽  
Frequency Magnitude

In this work, different types of power system faults at various distances have been identified using a novel approach based on Discrete S-Transform clubbed with a Fuzzy decision box. The area under the maximum values of the dilated Gaussian windows in the time-frequency domain has been used as the critical input values to the fuzzy machine. In this work, IEEE-9 and IEEE-14 bus systems have been considered as the test systems for validating the proposed methodology for identification and localization of Power System Faults. The proposed algorithm can identify different power system faults like Asymmetrical Phase Faults, Asymmetrical Ground Faults, and Symmetrical Phase faults, occurring at 20% to 80% of the transmission line. The study reveals that the variation in distance and type of fault creates a change in time-frequency magnitude in a unique pattern. The method can identify and locate the faulted bus with high accuracy in comparison to SVM.

Interaction of a Circular Cylindrical Shell with an Elastic Foundation

2018 ◽  
Vol 878 ◽  
pp. 3-7
Author(s):  
Vladimir I. Andreev ◽  
Andrey N. Leontiev
Keyword(s):  
Cylindrical Shell ◽  
Circular Cylindrical Shell ◽  
Rectangular Cross Section ◽  
Relative Length ◽  
Longitudinal Axis ◽  
Winkler Foundation ◽  
Total Moment ◽  
Relative Rigidity ◽  
Vertical Walls ◽  
The Impact

The problem of static analysis of a circular cylindrical shell, which is located on elastic Winkler foundation and reinforced by the longitudinal edges are considered. There is rib stiffness of rectangular cross section. Exposure is represented evenly distributed along the longitudinal axis forces. The forces acting on the edges of the rigidity of the upper structure. Agreed that the ends of the envelope is flat, vertical walls, giving the contour of the absolute rigidity in the transverse direction and does not prevent the longitudinal displacement of points of the envelope. To solve the problem, the total moment theory of circular cylindrical shell was used. To implement the proposed algorithm is the calculation of computer program. With the help of the program is executed a number of examples of calculation. In these examples, analyze the impact of stress on the shell of such factors as the relative length and thickness, angle mortar shell, the value of the relative rigidity of airborne elements and other.

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