Simulating and Detecting a Vibration-Induced Failure in an Air-Handling Assembly

2001 ◽  
Author(s):  
C. Gavin McGee ◽  
Douglas E. Adams
Keyword(s):  
Condition Based Maintenance ◽  
Spectral Signature ◽  
Structural Dynamic ◽  
Time Frequency ◽  
Mechanical Parts ◽  
Analysis Techniques ◽  
Contour Maps ◽  
Response Data ◽  
Processing Techniques ◽  
Signal Processing Techniques

Abstract Excessive vibrations usually cause mechanical parts to fail. This paper describes a vibration-induced failure in an air handling assembly. Cyclic impacts between a valve and a set of powdered metal bushings cause the failure. A variety of signal processing techniques are used to analyze experimental response data from the failing part including standard spectral signature approaches (i.e. Fourier, cepstral) in addition to more advanced time-frequency analysis techniques (i.e. wavelet contour maps). The theory and application of each method is reviewed in the context of the specific failure mode under consideration. The paper demonstrates that where friction or impact related vibrations are present, structural dynamic “health” monitoring schemes can be used to track changes in operating response signatures and schedule condition-based maintenance or re-design.

Signature Analysis Applied to Drilling

1982 ◽  
Vol 104 (2) ◽  
pp. 268-276 ◽  
Author(s):  
S. Braun ◽  
E. Lenz ◽  
C. L. Wu
Keyword(s):  
Signal Analysis ◽  
Drilling Process ◽  
Discrete Point ◽  
Time Frequency ◽  
Analysis Techniques ◽  
Processing Techniques ◽  
Twist Drills ◽  
The Relationship ◽  
Signal Processing Techniques ◽  
Drift Forces

This paper investigates the relationship between drill life, the sound, and the drift forces produced by the drilling process. Tests were performed while drilling steel with 38 in. twist drills. As a tool life criterion, the wear of the drill lips was monitored. Typical signals are described, and various signal processing techniques presented in view of characterizing them. These include time, frequency, and amplitude domain techniques. It is shown that specific signal patterns that occur with increasing lip wear show definite trends which can be followed by some analysis techniques. A discrete point process, derived from the signal’s spectrum, has been found specifically valuable. Results shown for actual data using these signal analysis techniques seem to support a theory of drill wear mechanism which was reported recently.

scholarly journals Multi-Domain Communication Systems and Networks: A Tensor-Based Approach

Network ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 50-74
Author(s):  
Divyanshu Pandey ◽  
Adithya Venugopal ◽  
Harry Leib
Keyword(s):  
Communication Systems ◽  
Physical Layer ◽  
Mathematical Framework ◽  
Trade Off ◽  
Information Theoretic ◽  
Time Frequency ◽  
Tensor Formulation ◽  
Processing Techniques ◽  
Multiple Domains ◽  
Signal Processing Techniques

Most modern communication systems, such as those intended for deployment in IoT applications or 5G and beyond networks, utilize multiple domains for transmission and reception at the physical layer. Depending on the application, these domains can include space, time, frequency, users, code sequences, and transmission media, to name a few. As such, the design criteria of future communication systems must be cognizant of the opportunities and the challenges that exist in exploiting the multi-domain nature of the signals and systems involved for information transmission. Focussing on the Physical Layer, this paper presents a novel mathematical framework using tensors, to represent, design, and analyze multi-domain systems. Various domains can be integrated into the transceiver design scheme using tensors. Tools from multi-linear algebra can be used to develop simultaneous signal processing techniques across all the domains. In particular, we present tensor partial response signaling (TPRS) which allows the introduction of controlled interference within elements of a domain and also across domains. We develop the TPRS system using the tensor contracted convolution to generate a multi-domain signal with desired spectral and cross-spectral properties across domains. In addition, by studying the information theoretic properties of the multi-domain tensor channel, we present the trade-off between different domains that can be harnessed using this framework. Numerical examples for capacity and mean square error are presented to highlight the domain trade-off revealed by the tensor formulation. Furthermore, an application of the tensor framework to MIMO Generalized Frequency Division Multiplexing (GFDM) is also presented.

Radiotechnical Signal Processing Techniques for Polymer Materials Structure Analysis

2017 ◽  
Vol 381 ◽  
pp. 59-63 ◽  
Author(s):  
Vladimir Klimentievitch Kachanov ◽  
Igor Vacheslavovitch Sokolov ◽  
Serguei Vladimirovitch Lebedev ◽  
Vladimir Vladimirovitch Pervushin
Keyword(s):  
Structure Analysis ◽  
Polymer Materials ◽  
Material Structure ◽  
New Approach ◽  
Time Frequency ◽  
Structure Assessment ◽  
Processing Techniques ◽  
Short Time ◽  
Signal Processing Techniques ◽  
Structure Inhomogeneity

Paper describes new approach to material structure analysis by means of ultrasound probing. Short-time Fourier transform and time-frequency analysis used to determine structure inhomogeneity present and perform structure condition assessment. Experimental results show possibilities of polymer materials structure assessment.

scholarly journals Characterization of Nonstationary Phase Noise Using the Wigner–Ville Distribution

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Chagai Levy ◽  
Monika Pinchas ◽  
Yosef Pinhasi
Keyword(s):  
Phase Noise ◽  
Nonstationary Processes ◽  
Time Frequency ◽  
Physical Mechanisms ◽  
Amplitude Fluctuations ◽  
Time Invariance ◽  
Processing Techniques ◽  
Oscillator Stability ◽  
Signal Processing Techniques

Oscillators and atomic clocks, as well as lasers and masers, are affected by physical mechanisms causing amplitude fluctuations, phase noise, and frequency instabilities. The physical properties of the elements composing the oscillator as well as external environmental conditions play a role in the coherence of the oscillatory signal produced by the device. Such instabilities demonstrate frequency drifts, modulation, and spectrum broadening and are observed to be nonstationary processes in nature. Most of the tools which are being used to measure and characterize oscillator stability are based on signal processing techniques, assuming time invariance within a temporal window, during which the signal is assumed to be stationary. This letter proposes a new time-frequency approach for the characterization of frequency sources. Our technique is based on the Wigner–Ville time-frequency distribution, which extends the spectral measures to include the temporal nonstationary behavior of the processes affecting the coherence of the oscillator and the accuracy of the clock. We demonstrate the use of the technique in the characterization of nonstationary phase noise in oscillators.

Vibration Analyses of the Bearing Using the Time Frequency Domain Technique

2014 ◽  
Vol 592-594 ◽  
pp. 2091-2096
Author(s):  
H.N. Sharma ◽  
Santosh Verma
Keyword(s):  
Fourier Transform ◽  
Wavelet Transform ◽  
Energy Levels ◽  
Vibration Signal ◽  
Test Rig ◽  
Time Frequency ◽  
Bearing Vibration ◽  
Processing Techniques ◽  
Signal Processing Techniques ◽  
Bearing System

This work employs the wavelet transform for reading the fault diagnosis in a rotor-bearing system. Initiating with literature review with some relevant studies of bearing fault and the signal processing techniques used followed by the theory of wavelet transform. A bearing test rig is shown which is used for implementing wavelet transform. A faulty bearing vibration signal is measured from the test rig; thereafter the fast Fourier transform is plotted to show the critical frequencies, bearing characteristics frequency and its harmonics. A scalogram showing the energy levels of signal is plotted as result. Faulty signal is analyzed using wavelet transform.

Derivation of Environment Descriptions and Test Severities from Measured Road Transportation Data

1993 ◽  
Vol 36 (1) ◽  
pp. 37-42
Author(s):  
Darrel Charles
Keyword(s):  
Random Vibration ◽  
Vibration Spectrum ◽  
Data Gathering ◽  
Measured Data ◽  
Road Transportation ◽  
Response Data ◽  
Useful Signal ◽  
Processing Techniques ◽  
Wheeled Vehicles ◽  
Signal Processing Techniques

This paper discusses the vibration and shock environments perceived by equipment when it is transported by wheeled vehicles. Methodologies are presented for deriving environment descriptions and test severities from measured road transportation dynamic response data. Measured responses from a data-gathering trial are used to illustrate a number of useful signal-processing techniques and the compilation of environment descriptions that quantify the severity and character of measured data. The environment description is used as the basis for the compilation of a test severity definition in terms of a random vibration spectrum and duration.

scholarly journals Cutting-edge Mathematical Tools in Processing and Analysis of Signals in Marine and Navy

2012 ◽  
Vol 1 (1) ◽  
pp. 35-46 ◽  
Author(s):  
Igor Vujović ◽  
Joško Šoda ◽  
Ivica Kuzmanić
Keyword(s):  
Decision Making ◽  
Signal Processing ◽  
Fourier Transform ◽  
Video Stream ◽  
Information Gathering ◽  
Pivotal Role ◽  
Surveillance Video ◽  
Time Frequency ◽  
Processing Techniques ◽  
Signal Processing Techniques

Signal processing plays a pivotal role in information gathering and decision making. This paper presents and compares different signal processing techniques used in marine and navy applications, primarily based on using wavelets as kernel. The article covers Fourier transform, time frequency wavelet based techniques such as bandelets, contourlets, curvelets, edgelets, wedgelets, shapelets, and ridgelets. In the example section of the paper, several transform techniques are presented and commented on the harbour surveillance video stream example.

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