scholarly journals Analisis Ketidaksesumbuan Poros (Misalignment) pada Rotordinamik Berdasarkan Sinyal Suara

2021 ◽  
Vol 12 (2) ◽  
pp. 487-495
Author(s):  
Dedi Suryadi ◽  
◽  
M Reza Febriyanto ◽  
Fitrilina Fitrilina
Keyword(s):  
Rotor Dynamics ◽  
Sound Signal ◽  
Peak Amplitude ◽  
Test Results ◽  
Motor Shaft ◽  
Angular Misalignment ◽  
Parallel Misalignment ◽  
Spectrum Characteristic ◽  
The Time Domain ◽  
Sound Spectrum

This research aims to identify misalignment of the rotor dynamics based on sound spectrum characteristic. In this study, rotor dynamics consist of motor, shaft, coupling and bearings. Three types of misalignment were considered, namely parallel, angular, and combination misalignment. In order to obtain the best signal, microphones were used as sensors to capture sound signal placed on coupling and each bearing. The signal obtained was in time series. The sound signal in the time domain is then filtered to remove noise signals, which are then transferred to be signals in the frequency domain using Fast Fourier Transform (FFT). From the test results, it is found that in the case of parallel misalignment, the sound frequency spectrum is obtained with a peak amplitude at 2x rpm. The case of angular misalignment obtained a sound spectrum with a peak amplitude value and is dominant at 1x rpm than 2x rpm. Meanwhile, in the case of a combination of parallel and angular misalignment, a peak amplitude sound spectrum appears at 1x rpm and 2x rpm with relatively close spacing between the peaks of the sound spectrum. The result shows that sound signal can be used for identification of misalignment of the rotor dynamics.

Analysis of the Effects of Parallel and Angular Misalignment in Hyperstatic Rotors Equipped With Oil-Film Bearings

2011 ◽  
Author(s):  
P. Pennacchi ◽  
A. Vania ◽  
S. Chatterton
Keyword(s):  
Reynolds Equation ◽  
Nonlinear Effects ◽  
Element Model ◽  
System Response ◽  
Angular Misalignment ◽  
Oil Film ◽  
Rotating Machine ◽  
Parallel Misalignment ◽  
Spectral Components ◽  
The Time Domain

Misalignment is one of the most common sources of trouble of rotating machinery having couplings between the shafts. Ideal alignment is a chimera and the coupling flanges of the shafts are never ideally aligned, presenting angular and/or parallel misalignment (defined also as radial misalignment or offset). In particular, during the shaft rotation, if coupling misalignment between the shafts of a statically aligned line is excessive, a periodical change, of the load on the bearings in hyperstatic shaft-lines, occurs. If the rotating machine is equipped with oil-film bearings, the change of the loads on the bearings causes also the variation of their oil-film dynamic characteristics, i.e. damping and stiffness, and the complete system cannot be considered as linear. In the paper, this phenomenon is modelled accurately and analyzed by considering the simulated response of a misaligned rotor train in the time domain. A finite element model is used for the hyperstatic rotor, while bearing characteristics are calculated by integrating Reynolds equation (considering the actual type and dimensions of the bearings) as a function of the instantaneous load acting on the bearings, caused by the coupling misalignment. Nonlinear effects are highlighted and the spectral components of system response are analyzed, in order to give pertinent diagnostic information.

scholarly journals Exhaust emission from a vehicle engine operating in dynamic states and conditions corresponding to real driving

2019 ◽  
Vol 178 (3) ◽  
pp. 99-105
Author(s):  
Monika ANDRYCH-ZALEWSKA ◽  
Zdzisław CHŁOPEK ◽  
Jerzy MERKISZ ◽  
Jacek PIELECHA
Keyword(s):  
Rotational Speed ◽  
Time Derivative ◽  
Exhaust Emission ◽  
Test Results ◽  
Engine Operation ◽  
Vehicle Engine ◽  
University Of Technology ◽  
The Time Domain ◽  
Speed Characteristic ◽  
Dynamic States

The article presents the exhaust emission results from a diesel engine in dynamic states of engine operation in the driving tests: NEDC (New European Driving Cycle) and Malta test, developed at the Poznan University of Technology. The NEDC and Malta tests were carried out as simulations on the engine test bench mimicking the driving tests conditions. The test results of the emission of carbon monoxide, hydrocarbons and nitrogen oxides obtained in each of the tests were presented. The dynamic states have been classified de-pending on the time derivative value of the torque and engine rotational speed. Both the positive and negative as well as zero time deriv-ative values of torque and rotational speed were considered. Therefore, overall six types of dynamic states were analyzed. A high sensi-tivity of exhaust emission to various types of dynamic states was found. The exhaust emission sensitivity to dynamic states in the Malta test was found to be higher than for the NEDC test, although these tests have similar properties (average rotational speed and average torque). This is due to the fact that the NEDC test is created on the basis of the similarity of zero-dimensional characteristics of the cars speed characteristic, whereas the Malta test was designed in accordance with the principle of faithful representation in the time domain of the NEDC speed curve.

scholarly journals MISALIGNMENT DISTANCE ANALYSIS OF VIBRATION AND NOISE VALUE

2020 ◽  
Vol 5 (2) ◽  
pp. 75-94
Author(s):  
Fathur Rahman Hidayat ◽  
Mastiadi Tamjidillah
Keyword(s):  
Angular Misalignment ◽  
Distance Analysis ◽  
Parallel Misalignment

Penelitian ini bertujuan untuk mengetahui nilai vibrasi yang terjadi pada saat misalignment 0,1, 0,2, 0,3, 0,4, dan 0,5 mm dan mengetahui nilai noise yang terjadi pada saat misalignment 0,1, 0,2, 0,3, 0,4, dan 0,5 mm. Variasi yang digunkan adalah parallel misalignment, angular misalignement dan combination misalignment dengan jarak misalignment 0,1, 0,2, 0,3, 0,4, dan 0,5 mm. Hasil penelitian menunjukkan untuk parallel misalignment vibrasi dan noise tertinggi terjadi pada saat parallel misalignment 0,5 posisi pengujian horizontal sebesar 8,97 mm/s overall velocity,   65,43 µm overall displacement, noise maximum 8 dB dan carpet -6 dB, sedangkan untuk angular misalignment vibrasi dan noise tertinggi terjadi pada saat angular misalignment 0,5 posisi pengujian axial sebesar 10,95 mm/s overall velocity, 76,95 µm overall displacement, noise maximum 5 dB carpet -11 dB dan untuk combination misalignment vibrasi dan noise tertinggi terjadi pada saat combination misalignment 0,5 posisi pengujian axial sebesar 16,33 mm/s overall velocity, 100,95 µm overall displacement noise maximum 13 dB dan carpet 3 dB.

A novel health indicator developed using filter-based feature selection algorithm for the identification of rotor defects

2020 ◽  
pp. 1748006X2091695 ◽  
Author(s):  
Anil Kumar ◽  
CP Gandhi ◽  
Xiaoyang Liu ◽  
Yi Liu ◽  
Yuqing Zhou ◽  
...  
Keyword(s):  
Feature Selection ◽  
Selection Process ◽  
Signal Frequency ◽  
Health Indicator ◽  
Angular Misalignment ◽  
Time Frequency ◽  
Vibration Data ◽  
Time Domain Signal ◽  
Frequency Representation ◽  
Parallel Misalignment

In this work, a novel health indicator is developed for the identification of rotor defects. The indicator is developed by extracting features from vibration data acquired from horizontal and vertical directions of rotors. A total of 38 features were initially extracted from time-domain signal, frequency-domain signal, and time–frequency representation. Out of many features, six most important features were selected using filter-based feature selection process. Thereafter, important features were fused together using manifold learning to develop health indicator. The developed indicator is used to identify misalignments (angular misalignment and parallel misalignment), rub, and unbalance. The major benefit of the proposed method is that it not only indicates the presence of defect in the rotor but also indicates the severity of defect. The experimental study presented in this article justifies that the proposed method is sensitive to the increasing levels of horizontal and angular misalignment and unbalance. The developed indicator is sensitive enough to indicate the presence of rub.

scholarly journals Application of L1 Trend Filtering Technology on the Current Time Domain Spectroscopy of Dielectrics

Electronics ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 1046
Author(s):  
Changyou Suo ◽  
Zhonghua Li ◽  
Yunlong Sun ◽  
Yongsen Han
Keyword(s):  
Time Series ◽  
Time Domain ◽  
Time Complexity ◽  
Time Range ◽  
Test Results ◽  
Current Time ◽  
Time Domain Spectroscopy ◽  
Filtering Algorithms ◽  
Wide Range ◽  
The Time Domain

The current time domain spectroscopy of dielectrics provides important information for the analysis of dielectric properties and mechanisms. However, there is always interference during the testing process, which seriously affects the analysis of the test results. Therefore, the effective filtering of current time domain spectroscopy is particularly necessary. L1 trend filtering can estimate the trend items exactly in a set of time series. It has been widely used in the fields of economics and sociology. Therefore, this paper attempts to apply L1 trend filtering to the current time domain spectroscopy. Firstly, polarization and depolarization currents are measured in the laboratory. Then the test results are filtered by L1 trend filtering and the filtering effects are compared with several common filtering algorithms, such as a sliding mean filter and Savitzky–Golay smoothing filter. Finally, the robustness and time complexity of L1 trend filtering are analyzed. The filtering results show that because the polarization currents vary in a wide range of the time domain (about 2–3 orders of magnitude), smooth and undistorted curves in the whole test time range can hardly be obtained through common filtering algorithms, while they can be obtained by L1 trend filtering. The results of robustness analysis and time complexity analysis show that L1 trend filtering can extract the trend items accurately in the time series under given different noise levels, and the execution time is also lower than 176.67 s when the number of tested points is no more than 20,000. Those results show that L1 trend filtering can be applied to the time domain current spectroscopy of dielectrics.

scholarly journals Dynamic Response of a Rotating Assembly under the Coupled Effects of Misalignment and Imbalance

2020 ◽  
Vol 2020 ◽  
pp. 1-26
Author(s):  
Mohamed Desouki ◽  
Sadok Sassi ◽  
Jamil Renno ◽  
Samer Abdelazim Gowid
Keyword(s):  
Numerical Model ◽  
Rotational Speed ◽  
Rotating Machinery ◽  
Angular Misalignment ◽  
Simultaneous Effect ◽  
Frequency Responses ◽  
Parallel Misalignment ◽  
Misalignment Fault ◽  
Coupling Type ◽  
Bearing System

In rotating machinery, the second most common fault after imbalance is misalignment. Misalignment can have a severe impact on equipment and may reduce the machine’s lifetime considerably. In this paper, the simultaneous effect of imbalance and misalignment (parallel or angular) on the vibration spectra of rotating machinery will be discussed. A numerical model is developed and used to obtain the time and frequency responses of the rotor-coupling-bearing system to the simultaneous effect of these faults. The numerical model shows that the imbalance was mainly related to the peak located around 1X, whereas misalignment was linked to the peak around 2X. In addition, the parallel misalignment fault magnifies the 2X amplitude of the displacement response, whereas the response of angular misalignment is captured at the 2X and 4X amplitudes. This study also examines the effects of changing the model’s rotational speed, misalignment level, and coupling type for angular and parallel misalignments.

scholarly journals Assessment of the Internal Catalyst Efficiency in a Diesel Engine of a Vehicle under the Conditions Simulating Real Driving

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6569
Author(s):  
Monika Andrych-Zalewska ◽  
Zdzisław Chłopek ◽  
Jerzy Merkisz ◽  
Jacek Pielecha
Keyword(s):  
Diesel Engine ◽  
Exhaust Emissions ◽  
Similarity Criteria ◽  
Vehicle Speed ◽  
Test Results ◽  
Engine Operation ◽  
Exhaust Gas Aftertreatment ◽  
Vehicle Operation ◽  
Unique Method ◽  
The Time Domain

The application of a catalyst on a surface inside a combustion chamber is known as a supplementary method of exhaust gas aftertreatment. The efficiency of this method in the reduction in exhaust emissions as well as its influence on other engine properties has been analyzed in multiple scientific works. Most often, these works present the results of investigations carried out on dynamometers under engine stationary conditions. There are no results of the catalyst investigations performed under dynamic states, particularly on-going real time analyses during engine operation. Therefore, the authors set out to explore the efficiency of the in-cylinder catalyst of a diesel engine under dynamic conditions simulating actual vehicle operation. A unique methodology was applied. The investigations were carried out in road conditions in a test simulating the New European Driving Cycle (NEDC) homologation test in compliance with the similarity criteria of the zero-dimensional characteristics of vehicle speed during the investigations and in the homologation test. For the research, the authors used portable exhaust emissions measurement equipment. A unique method of test results analysis was also applied (a continuous method in the time domain). As a result of the tests being repeated several times, it was observed that the application of an internal catalyst under different operating engine conditions repeatedly results in: an approx. 2% reduction in the emissions of carbon monoxide, hydrocarbons, and carbon dioxide; a similar increase in the emission of nitrogen oxides; and a significant (over 10%) reduction in the particle number. The obtained results substantiate the purpose of actions aiming at improving the efficiency of the internal catalyst.

Rotor Dynamics in Design of a High Speed Cryogenic Pump for Geo Stationary Launch Vehicles

2014 ◽  
Author(s):  
Srinivasa R. Jammi
Keyword(s):  
High Speed ◽  
Rotor Dynamics ◽  
Rotor System ◽  
Peak Amplitude ◽  
Beam Model ◽  
Rolling Element Bearings ◽  
Launch Vehicles ◽  
Critical Speeds ◽  
Highly Nonlinear ◽  
Rolling Element

On January 5th 2014 the Indian Space Research Organization successfully launched its Geo Stationary Launch Vehicle with an indigenous Cryogenic engine. One of the main design aspects is in its rotor dynamics to predict the peak amplitude unbalance whirl and the speed at which it occurs. This engine has several key technologies, one of them specifically is coupled rotors, viz., Turbine, Hydrogen Pump and Oxidizer supported on seven nonlinear rolling element bearings and several seals all mounted in a flexible casing. The conventional beam model initially adopted failed to predict the speed at which peak unbalance response occurs. The rotor system was first developed in a solid model to determine the critical speeds of the rotor alone considering its 40000 rpm centrifugal loads with bearings treated as linear. Then, unbalance whirl of this rotor system was developed by codes specially developed for this purpose. The rolling element bearings are found to be highly nonlinear with large bearing radial forces at critical speeds. An iterative procedure was developed to match the bearing force and unbalance whirl to determine peak amplitude response speeds. Subsequently, seals and the influence of casing and internal pressures were accounted in the analysis. This paper describes the advanced rotor dynamic design of this pump.

Tool Wear Monitoring Based on Milling Acoustic Spectrum LPCC

2012 ◽  
Vol 499 ◽  
pp. 353-358
Author(s):  
Chang Sheng Ai ◽  
Y.J. Sun ◽  
G.W. He
Keyword(s):  
Tool Wear ◽  
Sound Signal ◽  
Characteristic Parameters ◽  
Order Component ◽  
Acoustic Spectrum ◽  
Electret Microphone ◽  
Machining Center ◽  
Wear Monitoring ◽  
Spectrum Characteristic ◽  
Order Components

Cutting sound signal are acquisited in the vertical machining center using electret microphone, and would be applied to monitor tool wear. Linear Predictive Cepstrum Coefficient (LPCC) of milling sound signal within audibility threshold would be extracted as acoustic spectrum characteristic parameters, and the relativity between LPCC each order component and tools radial wear was analyzed. The experiments and analysis results conclude that there are characteristic components associated with tool wear in characteristic parameters LPCC of milling sound signal; the characteristic components associated with tool wear are mainly concentrated in the 6th, 7th and 8th order components LPCC; the method by characteristic parameters LPCC monitoring tool wear is feasible.

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