scholarly journals Experimental Research on the Influence of Working Conditions on Vibration and Temperature Rise of Si3N4 Full-Ceramic Bearing Motors

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Zhongxian Xia ◽  
Yuhou Wu ◽  
Hua Wei ◽  
Kexuan Ren ◽  
Longfei Gao ◽  
...  
Keyword(s):  
Working Conditions ◽  
Temperature Rise ◽  
Rotational Speed ◽  
Stable State ◽  
Vibration Signal ◽  
Spindle Motor ◽  
Normal Operation ◽  
Vibration Velocity ◽  
Ceramic Bearing ◽  
Lubrication Conditions

Working conditions such as lubrication, preload, and rotational speed have important influence on vibration and temperature rise of the spindle motor. In this study, controlled variable experiments are carried out on the silicon nitride (Si3N4) full-ceramic ball bearing and steel bearing of the same type, and the vibration signal characteristics and temperature rise of the spindle motor are tested and analysed, by changing the lubrication conditions, preloads, and rotational speeds of the spindle motor. Through the research, it is found that as the rotational speed increases, the vibration velocity of the Si3N4 full-ceramic bearing spindle motor under different preloads and lubrication conditions shows an overall increasing trend; kurtosis generally presents a downward trend and gradually flattens, indicating that although the vibration velocity increases at high speeds, the vibration signal shows a relatively stable state. As the rotational speed increases, the difference of vibration velocity under the condition of applying preload and no preload decreases, indicating that the influence of preload on the vibration of full-ceramic bearing spindle motor decreases with the increase in rotational speeds. At the same time, it is found that fr and 5fr have greater impact on the vibration of full-ceramic bearing spindle motor, where fr is the frequency of the bearing in normal operation, and 5fr is 5 times of the normal operating frequency. Lubrication conditions have little effect on the temperature rise of full-ceramic bearing spindle motor, and the temperature rise under nonlubricated conditions is even slightly lower than that under grease lubrication conditions. The research results show that the vibration velocity and temperature rise of Si3N4 full-ceramic bearing spindle motor are less than those of steel bearing with the same type, indicating that full-ceramic bearing has better performance than steel bearing under the same working conditions.

Feature extraction method of pipeline signal based on parameter optimized vocational mode decomposition and exponential entropy

2021 ◽  
pp. 014233122110294
Author(s):  
Yina Zhou ◽  
Yong Zhang ◽  
Jingyi Lu ◽  
Fan Yang ◽  
Hongli Dong ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Working Conditions ◽  
Acoustic Signals ◽  
Normal Operation ◽  
Local Characteristic ◽  
Support Vector ◽  
K Value ◽  
Feature Vectors ◽  
Mode Decomposition ◽  
Exponential Entropy

Pipeline leakage is the main reason that affects normal operation of the pipeline. In this paper, a feature recognition method for pipeline acoustic signals based on vocational mode decomposition (VMD) and exponential entropy (EE) is investigated, which could extract the characteristics of pipeline signals and further accurately identify the pipeline acoustic signals under different working conditions. First, the VMD is used to decompose the collected acoustic signals into a number of mode components, during which process the optimal mode number (i.e., K-value) is determined by combining local characteristic scale decomposition (LCD) and correlation analysis methods. Then, the characteristic content of each mode component is analyzed with the help of the determined correlation coefficient (CC) threshold. If the correlation coefficient of a mode component is greater than the threshold, then the mode component is selected as the feature component. Subsequently, the EE values of the selected feature components are calculated to form the feature vectors corresponding to different kinds of pipeline signals. Finally, the feature vectors are input into support vector machine (SVM) to classify and recognize the different pipeline states. The experimental results demonstrate that the proposed method can identify the pipeline signals under different working conditions, and the recognition accuracy is up to [Formula: see text]. By analyzing and comparing with methods of EE-SVM, original data-SVM, VMD-singular spectrum entropy (SSE) and VMD-information entropy (IE), it is further verified that the proposed method is feasible and superior to the methods.

The Analysis on the Tribological Properties of TPU/PVC Blends under Oil Lubrication

2013 ◽  
Vol 774-776 ◽  
pp. 94-98
Author(s):  
Dao Yuan Pan ◽  
Peng Peng Wu ◽  
Zhong Xue Gao ◽  
Yu Zeng Zhang
Keyword(s):  
Working Conditions ◽  
Friction And Wear ◽  
Oil Lubrication ◽  
Wear Properties ◽  
Operation Conditions ◽  
Hydraulic Steering ◽  
Pros And Cons ◽  
Friction And Wear Properties ◽  
Lubrication Conditions ◽  
Better Than

Based on actual working conditions and parameters of the hydraulic steering gear, the purpose is optimizing the rubber seal of steering gear by different rubbers mixing technology. Compare the five kinds of rubber with metal of the friction characteristics in dynamic fit, it can obtain a performance excellent rubber real in the specific operation conditions. And then improve the overall service life of the steering gear. It is first prepared the same hardness TPU and PVC and blends that the ratio is 3:7, 5:5and7:3 in this article. The pros and cons of the five rubbers are analyzed in friction and wear properties of the above experimental. The test curve of coefficient friction and wear with time has been done under different load at constant low speed. It determines TPU/PVC = 3:7 blends through friction and wear and wear mechanism of five rubbers with steel comparatively analyses, and the heat resistance and wear resistance of them are better than the other TPU/PVC blends and PVC under oil lubrication conditions.

scholarly journals Effects of Nanoparticle Enhanced Lubricant Films in Thermal Design of Plain Journal Bearings at High Reynolds Numbers

Symmetry ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1353 ◽  
Author(s):  
Abdollahzadeh Jamalabadi ◽  
Alamian ◽  
Yan ◽  
Li ◽  
Leveneur ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Shear Stress ◽  
Temperature Rise ◽  
Rotational Speed ◽  
Volume Fraction ◽  
Journal Bearings ◽  
Thermal Design ◽  
Average Shear Stress ◽  
Average Shear ◽  
Dissipation Power

Performance investigation of oil journal bearings is of particular importance given the growing use of them as a support for rotary components in a wide range of industrial machines. Frictional forces and shear stresses, which are proportionate to the velocity of lubricating layers at different points in the bearing space, provide the basis for changing temperature conditions. Various factors such as rotational velocity increase, slip width reduction, and small heat transfer coefficient of lubricant cause intensification of lubricant temperature changes. In the present study, with using computational fluid dynamic (CFD) thermohydrodynamic (THD) numerical simulations, the effect of nanoparticles on the performance features of plain journal bearings is evaluated. Particularly, 3D simulation of a journal bearing is implemented using CFD which considerably improves the accuracy of results, coupled with conjugate heat transfer model for metal parts of bearings. Reynolds equation model is used to calculate the oil-film pressure developed in hydrodynamic journal bearings by applying the nano-based lubricants. The configuration of thrust bearing consists of six pads in this study. In order to reduce the modeling complexity and computational cost and because of the symmetrical geometry of the pads, simulation of a single pad is considered instead of the entire domain. In this study, TiO2 nanoparticle with different volume fraction percentages are used. The parameters that are changed to evaluate the performance of the bearing include volume fraction percentage of the nanoparticle, type of lubricant, and rotational speed. Based on the results, for all different lubricant types, the dissipation power, average shear stress, and temperature rise are increased with augmenting the rotational speed. By increasing the rotational speed from 500 to 1500 rpm, the average shear stress increases by more than 100%, 120%, and 130% for DTE 26, DTE 25, and DTE 24 lubricant types, respectively. Moreover, by increasing the rotational speed from 500 to 1500 rpm, the dissipation power, and temperature rise are increased around 600% and 800%, respectively. Furthermore, increasing nanoparticles volume fraction from 0% to 10%, increases all parameters by approximately 10% for all lubricant types and in all rotational speeds.

Comparison of Piezoelectric Structural Damping Based on Velocity Controlled Switching and Pulse Width Modulation Switching Circuits

2012 ◽  
Author(s):  
Dejan Vasic ◽  
Yuan-Ping Liu ◽  
François Costa
Keyword(s):  
Pulse Width Modulation ◽  
Stable State ◽  
Piezoelectric Element ◽  
Voltage Source ◽  
Vibration Velocity ◽  
Constant Voltage ◽  
Vibration Displacement ◽  
Controlled Switching ◽  
The Stability ◽  
Piezoelectric Voltage

Two novel piezoelectric damping techniques (VSD and PWMD) are compared in this paper to the traditional resonant shunt damping technique and SSDV technique. In VSD, the switching shunt circuit turns ON or OFF according to the polarity of the vibration velocity of the host structure to shift the piezoelectric voltage phase. An external voltage source is connected to enlarge the voltage amplitude across the piezoelectric element and to optimize the dissipated power. The PWM shunt technique not only can decrease the audible noises more efficiently but also ensure the stability of the control system with a constant voltage source. The theoretical and the experimental results show that the piezoelectric voltage can be adaptive to the vibration displacement by the pulse widths variation, so the PWMD can stay in stable state with a constant voltage source and can still provide a very good performance.

scholarly journals Temperature Control at DBS Electrodes Using Heat Sinks: Experimentally Validated FEM Model of DBS Lead Architecture

2009 ◽  
Vol 3 (2) ◽  
Author(s):  
M. Elwassif ◽  
A. Datta ◽  
M. Bikson
Keyword(s):  
Thermal Conductivity ◽  
Temperature Field ◽  
Temperature Rise ◽  
Heat Sink ◽  
Magnetic Coupling ◽  
Heat Sinks ◽  
Peak Temperature ◽  
Normal Operation ◽  
Driving Voltage ◽  
Control Temperature

There is a growing interest in the use of Deep Brain Stimulation (DBS) for the treatment of medically refractory movement disorders and other neurological and psychiatric conditions. The extent of temperature increases around DBS electrodes during normal operation (joule heating and increased metabolic activity) or magnetic coupling (e.g., MRI) remain poorly understood, and methods to mitigate temperature increases are actively investigated. Indeed, brain function is especially sensitive to the changes in temperature including neuronal activity, metabolic functions, blood-brain barrier integrity, molecular stability, and viability. We developed technology to control tissue heating near DBS leads by modifying the thermal properties of lead materials. A micro-thermocouple was used to measure the temperature near DBS electrodes immersed in a saline bath. 3387 and 3389 Leads were energized using Medtronic DBS stimulators. The RMS of the driving voltage was monitored. Peak steady-state temperature was determined under different RMS values. A micro-positioning system was used, which allowed the generation of temperature field map. We developed and solved a finite element method (FEM) bio-heat transfer model of DBS incorporating realistic DBS lead architecture. The model was first validated using the experimental results (by matching saline thermal conductivity and electrical conductivity) and was then applied to develop methods to control temperature rises in the brain using heat-sink technology. Experimental measurements are consistent with theoretical predictions including: 1) Peak temperature increases directly with the RMS square of the applied voltage, such that different waveforms with the same RMS induce the same peak temperature rise; 2) Peak temperatures increases with contact proximity such the maximal temperature rise was observed using adjacent contacts of lead 3389; 3) Temperature decayed over ∼2 mm distance away from energized contacts. FEM results demonstrated the central role of lead materials (material properties and geometry) in controlling temperature rise by conducting heat: namely by acting as passive heat sinks. We report that the relatively high thermal conductivity of exiting DBS lead wiring affects the temperature field, indicating the importance of detailed lead architecture. We then demonstrate how modifying lead design to optimize heat conduction can effectively control temperature increases; the manifest advantages of this approach over complimentary heat-mitigation technologies is that heat-sink controls include: 1) insensitive to the mechanisms of heating (e.g., nature of magnetic coupling); 2) does not interfere with device efficacy (e.g., the electric fields induced in the tissue during stimulation are unaffected); and 3) can be practically implemented in a broad range of implanted devices (cardiac/neuro-prothethics, pumps...) without modifying device operation or implant procedure.

Pendeteksian Misalignment Menggunakan Multi Level Transformasi Wavelet Haar dan Coiflet pada Motor Induksi

2020 ◽  
Vol 1 (1) ◽  
pp. 1-6
Author(s):  
P.P.S Saputra
Keyword(s):  
Wavelet Transform ◽  
Discrete Wavelet Transform ◽  
Induction Motor ◽  
High Frequency ◽  
High Efficiency ◽  
Vibration Signal ◽  
Normal Operation ◽  
Discrete Wavelet ◽  
High Frequency Signal ◽  
Motor Operation

Currently induction motors are widely used in industry due to strong construction, high efficiency, and cheap maintenance. Machine maintenance is needed to prolong the life of the induction motor. As studied, bearing faults may account for 42% -50% of all motor failures. In general it is due to manufacturing faults, lack of lubrication, and installation errors. Misalignment of motor is one of the installation errors. This paper is concerned to simulation of discrete wavelet transform for identifying misalignment in induction motor. Modelling of motor operation is introduced in this paper as normal operation and two variations of misalignment. For this task, haar and coiflet discrete wavelet transform in first level until fifth level is used to extract vibration signal of motor into high frequency of signal. Then, energy signal and other signal extraction gotten from high frequency signal is evaluated to analysis condition of motor. The results show that haar discrete wavelet transform at thirth level can identify normal motor  and misalignment motor conditions well

Chaos Characteristics and Control of Permanent Magnet Synchronous Motors

2011 ◽  
Vol 48-49 ◽  
pp. 292-299 ◽  
Author(s):  
Wei Xue ◽  
Yan Ling Guo ◽  
Yong Li Li
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnet Synchronous Motor ◽  
Stable State ◽  
Nonlinear Dynamic System ◽  
Synchronous Motor ◽  
Normal Operation ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors ◽  
System Parameters ◽  
And Control

The permanent magnet synchronous motor (PMSM), a nonlinear dynamic system, can exhibit prominent chaotic characteristics under some choices of system parameters and external inputs. Based on a mathematical model of the permanent magnet synchronous motor, the existence of chaotic attractor is verified by the phase trajectory, Lyapunov exponent map and the bifurcation diagram. Chaotic phenomenon, such as a strong oscillation of speed and torque, unstable operating performance, affects the normal operation of motor. It makes the PMSM in a stable state to control chaos of the PMSM with a control strategy of infinitesimal geometry, which can eliminate chaos well.

Effects of rotational speed and feed rate on temperature rise, feed force and cutting torque when drilling bovine cortical bone

2012 ◽  
Author(s):  
J. Soriano ◽  
L. M. Iriarte ◽  
J. A. Eguren ◽  
P. Aristimuño ◽  
A. Garay ◽  
...  
Keyword(s):  
Cortical Bone ◽  
Temperature Rise ◽  
Feed Rate ◽  
Rotational Speed ◽  
Feed Force

scholarly journals SIGNAL PHASE SHIFTS DURING THE MEASUREMENT OF VIBRATION PARAMETERS

2020 ◽  
pp. 100-104
Author(s):  
Передерко А.Л., к.т.н.
Keyword(s):  
Vibration Signal ◽  
Wide Band ◽  
Phase Shifts ◽  
Vibration Velocity ◽  
Measured Signal ◽  
Mechanical Shock ◽  
Vibration Displacement ◽  
Active Vibration ◽  
Vibration Parameters ◽  
And Control

In systems of vibration control, monitoring, diagnostics, active vibration protection, measurements and control of vibration parameters are necessary. For this, piezoelectric sensors are widely used in them as primary transducers. These sensors, due to their high metrological characteristics, such as accuracy, speed, a wide band of operating frequencies and temperatures, are traditionally used to measure vibration displacement, vibration velocity and vibration acceleration. The use of these types of sensors is necessary due to the need to measure and control vibration at objects with different frequency characteristics. The article considers possible distortions of the measured signal at the output of the sensors due to phase shifts. These phase shifts must be taken into account when developing and constructing measurement and processing schemes of the vibration signal. This is especially true when measuring and recording a rapid vibration processes, such as mechanical shock.

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