MONITORING OF TORSIONAL VIBRATION OF A CRANKSHAFT BY INSTANTANEOUS ANGULAR SPEED OBSERVATIONS

2016 ◽  
Vol 23 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Mirosław Dereszewski
Keyword(s):  
Torsional Vibration ◽  
Angular Speed ◽  
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.

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

Influence of the Instantaneous Angular Speed (IAS) of Marine Diesel Engine on its Indication Results

2015 ◽  
Vol 236 ◽  
pp. 204-211
Author(s):  
Marek Łutowicz ◽  
Dominika Cuper-Przybylska
Keyword(s):  
Time Domain ◽  
Ad Hoc ◽  
Angular Speed ◽  
Time Axis ◽  
Crank Angle ◽  
Instantaneous Angular Speed ◽  
Marine Diesel ◽  
Angle Rotation ◽  
Crankshaft Rotation ◽  
Opening And Closing

The paper presents a method of transforming the time axis to the axis of the crank angle rotation based on the pressure measured in time domain and simplified model of the engine dynamics. Indicating is to register the pressure in synchronism with the engine crank angle rotation. Usually in the ad hoc measurements the crankshaft rotation angle transducer is avoided, and the measurements are performed in time domain. For further analysis time axis is transformed for crank angle axis on the base of linear transform. Pressure waveforms obtained during the research were subject of the described transform. During the research instantaneous angular speed (IAS) of the engine crankshaft has been changed by reducing fuel dosage to selected cylinders. Mean indicated pressure (MIP) was calculated. Values o pressure on the begging and the end of compression, opening and closing angles of valves were also determined.

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