scholarly journals Experimental Study on the Vibration of an Overhung Rotor with a Propagating Transverse Crack

2002 ◽  
Vol 9 (3) ◽  
pp. 91-104 ◽  
Author(s):  
S.A. Adewusi ◽  
B.O. Al-Bedoor
Keyword(s):  
Experimental Study ◽  
Steady State ◽  
Dynamic Response ◽  
Frequency Spectrum ◽  
Transverse Crack ◽  
Vibration Signal ◽  
Vibration Measurement ◽  
Side Load ◽  
Propagating Crack ◽  
Vibration Signatures

This paper presents an experimental study on the dynamic response of an overhung rotor with a propagating transverse crack. The effects of a propagating transverse crack and side load on the dynamic response of an overhung rotor are investigated in order to identify vibration signatures of a propagating crack in rotating shafts. Startup and steady state vibration signatures were analyzed and presented in the form of Bode plots, Frequency Spectrum Cascades, Frequency Spectrum Waterfalls and orbits. The startup results showed that crack reduces the critical speed and increases the vibration amplitude of the rotor system. It also excites 2X vibration in the startup vibration signatures. The steady state results showed that the propagating crack produces changes in vibration amplitudes of 1X and 2X vibration harmonics and excites 3X harmonic just before fracture. During crack propagation, 1X amplitude may increase or decrease depending on the location of the crack and the direction of vibration measurement while 2X amplitude always increases. The steady state vibration signal of a propagating crack also produces a two-loop orbit.

Experimental study on the dynamic response of a water ballast type floating breakwater

2021 ◽  
Vol 233 ◽  
pp. 109012
Author(s):  
Zhiwen Yang ◽  
Xinran Ji ◽  
Mingxiao Xie ◽  
Jinzhao Li ◽  
Huaqing Zhang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Dynamic Response ◽  
Floating Breakwater

Steady-State Dynamic Response of a Limited Slip System

1968 ◽  
Vol 35 (2) ◽  
pp. 322-326 ◽  
Author(s):  
W. D. Iwan
Keyword(s):  
Steady State ◽  
Dynamic Response ◽  
Slip System ◽  
External Load ◽  
Initial Conditions ◽  
Viscous Damping ◽  
Steady State Response ◽  
Response Curves ◽  
State Response ◽  
System Nonlinearity

The steady-state response of a system constrained by a limited slip joint and excited by a trigonometrically varying external load is discussed. It is shown that the system may possess such features as disconnected response curves and jumps in response depending on the strength of the system nonlinearity, the level of excitation, the amount of viscous damping, and the initial conditions of the system.

Small scale experimental study of the dynamic response of a tension leg platform wind turbine

2014 ◽  
Vol 6 (5) ◽  
pp. 053108 ◽  
Author(s):  
Anders Mandrup Hansen ◽  
Robert Laugesen ◽  
Henrik Bredmose ◽  
Robert Mikkelsen ◽  
Nikolaos Psichogios
Keyword(s):  
Experimental Study ◽  
Dynamic Response ◽  
Wind Turbine ◽  
Small Scale ◽  
Tension Leg Platform

Research on Shearer Rocker Gearbox Fault Location Based on Wavelet Envelope Demodulation

2014 ◽  
Vol 528 ◽  
pp. 210-216
Author(s):  
Zeng Qiang Wang ◽  
Hong Wei Ma ◽  
Mei Hua Tao ◽  
Xu Hui Zhang ◽  
Qing Hua Mao
Keyword(s):  
Fourier Transform ◽  
Frequency Spectrum ◽  
Spectrum Analysis ◽  
Fault Location ◽  
Vibration Signal ◽  
Morlet Wavelet ◽  
Frequency Spectrum Analysis ◽  
Mechanical Faults ◽  
Faults Diagnosis ◽  
Feature Frequency

To solve the problem of faults location for shearer rocker gearbox, the multiple sites vibration signal of faulty rocker gearbox are collected, as well as the Morlet wavelet envelope demodulation is applied to demodulate vibration signal and Fourier transform is used to carry out frequency spectrum analysis of vibration signal. Experimental results show that this method can effectively extract the faults feature frequency from complex vibration signal. The faults location result is consistent with actual faults part. This mean realizes to locate faults accurately. It provides an effective method for mechanical faults diagnosis of shearer.

Experimental Study on Lateral and Torsional Vibration of Cracked Rotor With Torsional Excitation

2013 ◽  
Author(s):  
Chao Liu ◽  
Dongxiang Jiang
Keyword(s):  
Experimental Study ◽  
Normal Condition ◽  
Torsional Vibration ◽  
Transverse Crack ◽  
Rotating Machinery ◽  
Lateral Vibration ◽  
Cracked Rotor ◽  
Diagnostic Features ◽  
Slant Crack ◽  
Torsional Excitation

Crack failures in rotating machinery can result in catastrophic accidents, and they are are difficult to detect online. Condition monitoring is widely applied in field to detect changes of vibration, and form diagnostic features. However, effective features in vibration of the cracked rotor need more tests, especially validating the features with experiments. This work carried out an experimental study on cracked rotors in laboratory. The experiments are as following: (I) vibration of the rotor in normal condition is firstly tested, where lateral vibration and torsional vibration are measured; (II) torsional excitation is exerted on driven end of rotor system, and vibration characteristics of the rotor are tested; (III) cracked rotors are tested with transverse and slant cracks, respectively. With the measured signals, comparisons of vibrations in normal rotor and cracked rotors are carried out. The results show that, the transverse crack introduces more significant changes in 1X frequency and coupled frequency, while the slant crack employs larger changes in 2X frequency. And variation of phases of 1X frequency is presented. Also, the crack plays an impact on the torsional responses.

Use of a Pendulum for Passive Structural Vibrations Control: An Experimental Study

1993 ◽  
Author(s):  
A. Ertas ◽  
O. Cuvalci
Keyword(s):  
Experimental Study ◽  
Dynamic Response ◽  
Passive Control ◽  
Control Device ◽  
Structural Vibrations ◽  
Pendulum System ◽  
Series Of Experiments ◽  
Tip Mass

Abstract The dynamic response of a beam-tip mass-pendulum system subjected to sinusoidal excitations is considered. The conditions under which resonant and nonresonant oscillations occur are investigated and discussed. The main objective of this study was to conduct a series of experiments to investigate the autoparametric interaction between the first two modes of the system. The use of a pendulum as a passive control device was experimentally evaluated.

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