Delay-line speed-up devices for analysis of random vibration data

1964 ◽  
Vol 52 (2) ◽  
pp. 219-220
Author(s):  
A.G. Ratz
Keyword(s):  
Random Vibration ◽  
Delay Line ◽  
Vibration Data ◽  
Line Speed ◽  
Speed Up

Delay-line speed-up devices for analysis of random vibration data

1964 ◽  
Vol 52 (10) ◽  
pp. 1263-1263
Author(s):  
M.N. Kaufman ◽  
A.G. Ratz
Keyword(s):  
Random Vibration ◽  
Delay Line ◽  
Vibration Data ◽  
Line Speed ◽  
Speed Up

Inductive Estimation Arithmetic for Random Vibration Data

2011 ◽  
Vol 219-220 ◽  
pp. 1113-1116
Author(s):  
Yong Jie Zhang ◽  
Xiao Hu Zhang ◽  
Bin Tuan Wang
Keyword(s):  
Data Processing ◽  
Numerical Experiments ◽  
Random Vibration ◽  
Measured Data ◽  
Reliability Test ◽  
Vibration Data ◽  
Inductive Methods

The vibration data processing of environmental spectrum is an important part of environmental reliability test for the aircraft. Based on the inductive methods for environmental measured data of vibration, an inductive arithmetic is employed to estimate the random vibration data of aircraft surface in Matlab system. Numerical experiments show that the inductive estimation arithmetic is effective, reliable and applicable for the environmental measured data of random vibration.

scholarly journals Application of a computer sound card for measurement of mechanical vibrations

2015 ◽  
Vol 37 (4) ◽  
pp. 4313-1-4313-6
Author(s):  
Everaldo de Barros ◽  
Carlos d'Andrade Souto ◽  
Leandro Ribeiro de Camargo ◽  
Mauro Hugo Mathias
Keyword(s):  
Data Acquisition ◽  
Random Vibration ◽  
Measurement Instrument ◽  
Digital Signal ◽  
Time Spectrum ◽  
Vibration Monitoring ◽  
Sound Card ◽  
Mechanical Vibrations ◽  
Vibration Data ◽  
Analysis System

This paper presents a data acquisition and analysis system based on a computer sound card for measuring and processing random vibration signals. This system turns the computer into a two-channel measurement instrument which provides sample rate, simultaneous sampling, frequency range, filters and others essential capabilities required to perform random vibrations measurements. An easy-to-use software was developed for vibration monitoring and analysis, including facilities for data recording, digital signal processing and real time spectrum analyzer. Since the tasks of vibration data acquisition frequently require expensive hardware and software, this versatile system provides students a very accurate and inexpensive solution for experimental studying mechanical vibrations.

Generalized Random Decrement Method for Analysis of Vibration Data

1998 ◽  
Vol 120 (3) ◽  
pp. 806-813 ◽  
Author(s):  
P. D. Spanos ◽  
B. A. Zeldin
Keyword(s):  
Correlation Function ◽  
Random Vibration ◽  
Gaussian Random Process ◽  
White Noise Process ◽  
Vibration Data ◽  
Auto Correlation ◽  
Random Decrement ◽  
Auto Correlation Function ◽  
Random Decrement Method ◽  
Theoretical Developments

The Random Decrement method used in system identification for analysis of random vibration data is considered from a rigorous mathematical perspective. It is shown that the Random Decrement signature deviates from the system free vibration curve of an associated linear system, unless the corresponding input excitation is white. The error induced by approximating the system excitation by a white noise process is examined. Further, a generalized Random Decrement signature is introduced; it is used to estimate efficiently the auto-correlation function of an ergodic Gaussian random process. Several examples are discussed to elucidate the theoretical developments.

Experimental Investigation of Dynamic Nonlinearities in Rotating Machinery

1997 ◽  
Author(s):  
Georgios A. Horattas ◽  
Maurice L. Adams ◽  
Mohammed F. Abdel Magied ◽  
Kenneth A. Loparo
Keyword(s):  
Hysteresis Loop ◽  
Computer Simulations ◽  
Spectrum Analysis ◽  
Dynamical Behavior ◽  
Practical Importance ◽  
Vibration Data ◽  
Oil Whip ◽  
Saddle Node ◽  
Speed Up ◽  
Complex Dynamical Behavior

Abstract This paper presents laboratory experiments that confirm and further explore earlier computer simulations related to oil-whip and rub-impact. Both phenomena were explored using Spectrum Analysis, and Chaos tracking techniques (e.g. Poincare’ maps). The results show that oil-whip induces quasi-periodic rotor vibrations, while rub-impact generates complex dynamical behavior, such as chaotic vibrational motion. The nonlinear oil-whip hysteresis loop results presented confirm phenomena uncovered in previous computer simulations. A Sommerfeld number-consistent “instability threshold load” was experimentally observed, along with its corresponding hysteresis loop similar to the classic instability speed hysteresis loop, but probably the most important experimental discovery was a second Hopf bifurcation-Saddle node instability hysteresis loop (i.e., at higher speed than the classical hysteresis loop), separated by a region of stable-in-the-small operation. Another result of especially high practical importance, was the discovery that spectrum analysis of speed-up, or coast-down rotor-vibration data can be effectively used to locate the saddle node speed.

Recovery of Modal Information From a Beam Undergoing Random Vibration

1974 ◽  
Vol 96 (4) ◽  
pp. 1307-1313
Author(s):  
W. W. Parmenter ◽  
R. G. Christiansen
Keyword(s):  
Fourier Transform ◽  
Structural Analysis ◽  
Fast Fourier Transform ◽  
Random Process ◽  
Random Vibration ◽  
Structural Information ◽  
Process Theory ◽  
Acceleration Response ◽  
Vibration Data ◽  
Random Process Theory

An organized approach for implementing the techniques of random process theory in the recovery of structural information from random vibration data is presented. The boundaries of various configured Bernoulli-Euler like beams are subjected to random vibrations and the acceleration response of these beams is measured and recorded. The Fast Fourier Transform (FFT) makes the use of random process theory both a feasible and economical tool for experimental structural analysis.

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