Evaluation and Improvement of Accuracy in the Instantaneous Angular Speed (IAS) and Torsional Vibration Measurement Using Zebra Tapes

2015 ◽  
pp. 43-56 ◽  
Author(s):  
Antonio Palermo ◽  
Karl Janssens ◽  
Laurent Britte
Keyword(s):  
Torsional Vibration ◽  
Angular Speed ◽  
Vibration Measurement ◽  
Instantaneous Angular Speed

scholarly journals Vibration Analysis of a Single-Cylinder Reciprocating Compressor considering the Coupling Effects of Torsional Vibration

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Siyuan Liu ◽  
Wanyou Li ◽  
Zhijun Shuai ◽  
Meilong Chen
Keyword(s):  
Torsional Vibration ◽  
Vibration Analysis ◽  
Transfer Functions ◽  
Cylinder Liner ◽  
Angular Speed ◽  
Reciprocating Compressor ◽  
Connecting Rod ◽  
Single Cylinder ◽  
Rotating Speed ◽  
Instantaneous Angular Speed

A piston slap is one of the main vibration sources of the reciprocating machinery. Much work has been done in this field, most of which was based on a constant rotating speed. However, in practice, the speed of a crankshaft may always fluctuate due to the uneven load or excitation. The inertia forces of moving components are much different at the fluctuating rotating speed comparing with that at a constant speed. In this paper, the piston slap and the induced vibration are analyzed based on the instantaneous angular speed measured on a single-cylinder reciprocating compressor. Firstly, the dynamics of a crank-connecting rod mechanism is analyzed based on the measured instantaneous angular speed which contains the torsional vibration of the air compressor. The time histories of piston slap impact forces considering and without considering torsional vibration are compared. Then, in order to correlate the piston slap impact with the slap-induced vibration, the corresponding transfer functions between the middle stroke of the outer surface of the cylinder liner and the excitation points are measured. And the excitation force on the main bearing is also taken into account to bring the simulation closer to the experimental results. The effects of a torsional vibration on the vibration of the cylinder liner are analyzed, and the simulation results show that the torsional vibration is a factor that must be taken into account in the vibration analysis of the single-cylinder reciprocating compressor.

Torsional Vibration Extraction of Dual-Period Instantaneous Angular Speed Measurement of the Generalized Incremental Encoder

2021 ◽  
Author(s):  
Zhang Yuhao ◽  
Yujiong Gu ◽  
Pengcheng Zhao ◽  
Dongchao Chen ◽  
Kun Yang
Keyword(s):  
Torsional Vibration ◽  
Calculation Method ◽  
Vibration Signal ◽  
Angular Speed ◽  
Angular Motion ◽  
Signal Sampling ◽  
Time Component ◽  
Instantaneous Angular Speed ◽  
Incremental Encoder ◽  
The Relationship

Abstract Torsional vibration is key information in monitoring the condition of the shaft system. Using the vector superposition principle, the relationship between the rotation motion and the torsional vibration of the shaft is analyzed. This paper proposes a generalized incremental encoder model and constructs a piecewise function to describe the principle of the pulse output type speed measuring device. The incremental encoder uses a fixed angular increment to stamp the time component of the angular motion of the shaft, thereby establishing a discrete relationship between the angular motion of the shaft and the time component. The relationship between the angular resolution of the encoder and the torsional vibration signal sampling theorem is deduced. The asymmetric under-sampling of the torsional vibration signals is explained from the perspective of signal sampling. According to the index period invariance of the reconstruction of the encoder disc angle sequence, a double-period instantaneous angular speed (IAS) calculation method is proposed, which uses all the time stamps, avoiding the sampling bandwidth idle caused by the single period method, causing the torsional vibration signal to obtain more detailed information, and its analysis bandwidth is twice that of the single-period method. Simulation and experiment verified the correctness and superiority of the research content. Finally, the calculation method was packaged as a functional module and embedded in an online torsional vibration monitoring device applied to two 1000Mw nuclear power turbine generator sets.

scholarly journals Experimental Study of the Shaft Penetration Factor on the Torsional Dynamic Response of a Drive Train

Machines ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 31 ◽  
Author(s):  
Hans Meeus ◽  
Björn Verrelst ◽  
David Moens ◽  
Patrick Guillaume ◽  
Dirk Lefeber
Keyword(s):  
Experimental Study ◽  
Torsional Vibration ◽  
Torsional Stiffness ◽  
Vibration Measurement ◽  
Dynamic Amplification Factor ◽  
Torsional Mode ◽  
Penetration Factor ◽  
Torsional Response ◽  
Major Interest ◽  
Drive Trains

Typical rotating machinery drive trains are prone to torsional vibrations. Especially those drive trains that comprise one or more couplings which connect the multiple shafts. Since these vibrations rarely produce noise or vibration of the stationary frame, their presence is hardly noticeable. Moreover, unless an expensive torsional-related problem has become obvious, such drive trains are not instrumented with torsional vibration measurement equipment. Excessive levels can easily cause damage or even complete failure of the machine. So, when designing or retrofitting a machine, a comprehensive and detailed numerical torsional vibration analysis is crucial to avoid such problems. However, to accurately calculate the torsional modes, one has to account for the penetration effect of the shaft in the coupling hub, indicated by the shaft penetration factor, on the torsional stiffness calculation. Many guidelines and assumptions have been published for the stiffness calculation, however, its effect on the damping and the dynamic amplification factor are less known. In this paper, the effect of the shaft penetration factor, and hence coupling hub-to-shaft connection, on the dynamic torsional response of the system is determined by an experimental study. More specifically, the damping is of major interest. Accordingly, a novel academic test setup is developed in which several configurations, with each a different shaft penetration factor, are considered. Besides, different amplitude levels, along with both a sweep up and down excitation, are used to identify their effect on the torsional response. The measurement results show a significant influence of the shaft penetration factor on the system’s first torsional mode. By increasing the shaft penetration factor, and thus decreasing the hub-to-shaft interference, a clear eigenfrequency drop along with an equally noticeable damping increase, is witnessed. On the contrary, the influence of the sweep up versus down excitation is less pronounced.

Design of a wire measurement system for dynamic feeding TIG welding using instantaneous angular speed

2018 ◽  
Vol 101 (5-8) ◽  
pp. 1651-1660 ◽  
Author(s):  
Régis Henrique Gonçalves e Silva ◽  
Luiz Eduardo dos Santos Paes ◽  
Gustavo Luis de Sousa ◽  
Cleber Marques ◽  
Alberto Bonamigo Viviani ◽  
...  
Keyword(s):  
Measurement System ◽  
Angular Speed ◽  
Tig Welding ◽  
Instantaneous Angular Speed

scholarly journals A Fiber Bragg Grating Based Torsional Vibration Sensor for Rotating Machinery

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2669 ◽  
Author(s):  
Jingjing Wang ◽  
Li Wei ◽  
Ruiya Li ◽  
Qin Liu ◽  
Lingling Yu
Keyword(s):  
Optical Fiber ◽  
Fiber Bragg Grating ◽  
Torsional Vibration ◽  
Electromagnetic Interference ◽  
Vibration Sensor ◽  
Vibration Measurement ◽  
Bragg Grating ◽  
Structural Parameter ◽  
Measurement Sensitivity ◽  
Fiber System

This paper proposes a new type of torsional vibration sensor based on fiber Bragg grating (FBG). The sensor has two mass ball optical fiber systems. The optical fiber is directly treated as an elastomer and a mass ball is fixed in the middle of the fiber in each mass ball fiber system, which is advantageously small, lightweight, and has anti-electromagnetic interference properties. The torsional vibration signal can be calculated by the four FBGs’ wavelength shifts, which are caused by mass balls. The difference in the two sets of mass ball optical fiber systems achieves anti-horizontal vibration and anti-temperature interference. The principle and model of the sensor, as well as numerical analysis and structural parameter design, are introduced. The experimental conclusions show that the minimum torsional natural frequency of the sensor is 27.35 Hz and the torsional vibration measurement sensitivity is 0.3603 pm/(rad/s2).

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