scholarly journals Re-Design of Machine Tool Joint Components Based on Polymer Fillings for High-Speed Performance

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6913
Author(s):  
Zuzana Murčinková ◽  
Pavel Adamčík ◽  
Jozef Živčák
Keyword(s):  
Acoustic Emission ◽  
High Frequency ◽  
High Speed ◽  
Dynamic Properties ◽  
Hybrid Structure ◽  
Particulate Composites ◽  
High Frequency Signal ◽  
Structural Modifications ◽  
Speed Performance

In this paper, we report the results of an experimental study of a re-design approach using filling polymers and particulate composites with a polymer matrix, thus creating a macroscopic hybrid structure. The re-design is focused on the joint of a textile machine. It is a re-design of already existing machine parts of a joint in order to increase the damping of components, reduce the amplitudes of high-frequency vibrations and acoustic emission for high-speed operation of textile rotors, and to compare individual structural modifications of the rotor housing body and absorber of high-speed textile rotor in a spinning unit with respect to dynamic properties of that measured mechanical system. The experiments included a bump test, determination of logarithmic decrement, measurement of vibration acceleration, a wavelet analysis, and measurement of acoustic emission. When excited by high frequency signal amplitudes up to 5 g, the benefits of polymer filling were manifested by an approximately 50% reduction in amplitude vibrations, a 66% reduction in acoustic emission amplitude, and an 85% reduction of the maximum peak in the acoustic emission FFT spectrum. In the area above 10 g, the stiffness of the component dominated to reduce the magnitude of vibrations.

Process Optimization of Ultrasonic Shot Peening by Realistic Modeling of Beads Motion

2014 ◽  
Author(s):  
Alexandre Brosse ◽  
Simon Le Moal ◽  
Rémi Lacroix ◽  
Philippe Mourgue ◽  
Vincent Robin ◽  
...  
Keyword(s):  
Numerical Model ◽  
Shot Peening ◽  
High Frequency ◽  
High Speed ◽  
Nuclear Industry ◽  
Input Frequency ◽  
Realistic Modeling ◽  
Ultrasonic Shot Peening ◽  
Small Steel

In the nuclear industry surface mechanical treatments are used in order to improve the surface integrity of the component, which increases their lifetime regarding corrosion and fatigue damages. A good understanding of these processes and their consequences is required to ensure the efficiency and perpetuity of such mitigation treatment. This study focuses on the ultrasonic shot peening process. It consists in shooting at high speed small steel beads on the part to be treated by using a high frequency vibration device. Parameters such as the number and the size of beads, the input frequency and the dimensions of the chamber can induce large ranges of impact velocity and coverage. In order to help manufacturers to control the treatment applied on their components, a numerical model has been developed. It accounts for the shocks of the beads against the walls of the chamber, the peening head and between beads, describing their motions accurately. In this paper, we will introduce the numerical model developed to simulate the motions of beads in the peening chamber. Special attention will be taken to the determination of the restitution rates related to the different materials. Results of the model will be shown for different process parameter (e.g. the number of beads), and a thorough analysis of their effects on the workpiece will be presented, including a comparison with some experimental results.

scholarly journals Research into Correlation between the Lubrication Mode of Contact Surfaces and Dynamic Parameters of Turbo-Generator Transmissions

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Marek Kočiško ◽  
Petr Baron ◽  
Monika Telíšková ◽  
Jozef Török ◽  
Anna Bašistová
Keyword(s):  
Acoustic Emission ◽  
High Frequency ◽  
High Speed ◽  
Oil Quality ◽  
The State ◽  
Dynamic Parameters ◽  
High Frequency Vibration ◽  
Turbo Generator ◽  
Friction Mode ◽  
Contact Surfaces

The paper presents the results of an experimental study aimed at assessing the correlation between the measurement of dynamic parameters (vibration, high-frequency vibration, and acoustic emission) and the analysis of friction mode and the state of lubrication of the contact surfaces of two gearboxes in the turbo-generator assembly (high-speed single-body steam turbine—gearbox—generator) with the transmission power of no more than 50 MW. The analysis confirmed the assumption of a significant correlation of the monitored high-frequency vibration signal with the unsatisfactory engagement of the gear teeth. Through vibration analysis, an increased level of the tooth vibration component and vibration multiples with increased acoustic emission were identified in gearbox operation. The gear oil of one of the gearboxes examined showed a loss of additive elements in the real operation of the contact surfaces of the teeth engagement. The trend analysis confirmed the complexity of the monitored transmission operation in terms of the friction mode and the influence of the oil quality on the state of the tooth flank microgeometry.

Combined Back-EMF Estimator with High-Frequency Signal Injection for Wide Speed Range Sensorless Control of PMLSM

2013 ◽  
Vol 753-755 ◽  
pp. 1405-1408
Author(s):  
Hua Cai Lu ◽  
Xuan Yu Yao ◽  
Juan Ti
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Sensorless Control ◽  
Estimation Method ◽  
Detection Algorithm ◽  
Estimation Accuracy ◽  
High Frequency Signal ◽  
Weighting Method ◽  
Transition Speed ◽  
Signal Injection

This paper describes a composite sensorless position and speed detection algorithm designed for permanent magnet linear synchronous motor (PMLSM). A high-frequency voltage signal injection method is used at starting and low speed, and a back-EMF integrate method is used at high speed, and the two kinds of method are fused by weighting method in the transition speed area. Simulation results show that estimation accuracy of this composite estimation method is satisfactory, and the sensorless control system based on this method has good dynamic response characteristics within full speed.

scholarly journals Experimental Investigation of the Diagnosis of Angular Contact Ball Bearings Using Acoustic Emission Method and Empirical Mode Decomposition

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Ramtin Tabatabaei ◽  
Aref Aasi ◽  
Seyed Mohammad Jafari ◽  
Enrico Ciulli
Keyword(s):  
Acoustic Emission ◽  
Empirical Mode Decomposition ◽  
High Speed ◽  
Early Stage ◽  
Signal To Noise Ratio ◽  
Operating Conditions ◽  
Outer Race ◽  
Mode Decomposition ◽  
Speed Performance ◽  
Envelope Spectrum

Early detection of angular contact bearings, one of the important subsets of rolling element bearings (REBs), is critical for applications of high accuracy and high speed performance. In this study, acoustic emission (AE) method was applied to an experimental case with defects on angular contact bearing. AE signals were collected by AE sensors in different operating conditions. Signal to noise ratio (SNR) was calculated by kurtosis to entropy ratio (KER), then acquired signals were denoised by empirical mode decomposition (EMD) method, and optimal intrinsic mode function (IMF) was selected by the proposed method. Finally, envelope spectrum was applied to the denoised signals, and frequencies of defects were obtained in different rotating speeds, loadings, and defect sizes. For the first time, a small defect with width of 0.3 mm and loading of 475 N was detected in early stage of 0.04 KHz. Moreover, a comparison between theoretical and extracted defect frequencies suggested that our method successfully detected localized defects in both inner and outer race. Our results show promise in detecting small size defects in REBs.

Study on High-Speed Switch Shifting Solenoid Current Control Technology for Automatic Transmission

2014 ◽  
Vol 1006-1007 ◽  
pp. 639-642
Author(s):  
Chun Fu Li ◽  
Yan Qin Li
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Automatic Transmission ◽  
Current Control ◽  
Control Technology ◽  
Working Process ◽  
Frequency Signal ◽  
High Frequency Signal ◽  
Long Time ◽  
The Ideal

The purpose of the solenoid current control is to decrease holding current of the solenoid by selecting suitable frequency and duty, to keep the solenoid opening reliably for a long time and reduce power consumption and improve the solenoid close feature. In this paper, the high frequency signal in oil pressure holding process is determined by theoretical analysis and experimental study. The purpose of the study is to determine the ideal current in the working process of the solenoid.

scholarly journals Comparing the broadband acoustic frequency response of single, clustered, and arrays of marine air guns

Geophysics ◽  
2020 ◽  
Vol 85 (3) ◽  
pp. P27-P36
Author(s):  
Martin Landrø ◽  
Jan Langhammer
Keyword(s):  
Acoustic Signal ◽  
High Frequency ◽  
High Speed ◽  
Acoustic Stimulation ◽  
Main Peak ◽  
Water Tank ◽  
High Frequency Signal ◽  
Acoustic Frequency ◽  
Air Gun ◽  
Marine Air

Field data acquired from a seismic vessel by a seabed hydrophone is used to analyze the broadband response (10 Hz to 62.5 kHz) for various source configurations: single air guns, clustered air guns, and a full array consisting of 30 air guns. The various parts of the acoustic signal are analyzed in detail, and it is found that a high-frequency signal arriving prior to the main peak of a single air-gun signal most likely is caused by small vapor cavities collapsing at or close to the surface of the gun. This is confirmed by high-speed photographs taken when a small air gun is fired in a water tank. When the full array is used, a second type of cavitation signal is observed: ghost cavitation caused by acoustic stimulation by the negative pressure that is backscattered from the free surface. As this ghost signal from 30 different guns arrives at a specific location in the water, cavities might be formed, and they create a high-frequency acoustic signal.

High Frequency Signal Propagation in Through Silicon Vias

2012 ◽  
Vol 2012 (1) ◽  
pp. 000239-000243
Author(s):  
Srinidhi Raghavan Narasimhan ◽  
A. Ege Engin
Keyword(s):  
Wave Propagation ◽  
High Frequency ◽  
High Speed ◽  
Signal Propagation ◽  
Successful Implementation ◽  
High Frequency Signal ◽  
3D Ic ◽  
Through Silicon Vias ◽  
Integration Technology ◽  
Silicon Vias

The 3D IC integration technology and silicon interposers rely on through silicon vias (TSVs) for vertical interconnections. Hence, the medium carrying high frequency signals is lossy silicon (Si). Fundamental understanding of wave propagation through TSVs is essential for successful implementation of 3D IC integration technology as well as for the development of Si interposers at RF/microwave frequencies. The focus of this paper is characterization and modelling of TSVs and Si to explore high speed signal propagation through the lossy Si medium. To understand better the physical significance of the TSV, we will establish a framework for wave propagation through TSVs based on dielectric quasi-TEM, skin effect, and slow-wave modes similar to MIS micro-strip lines. For validation of the existence of these modes, full wave simulation results will be compared with simpler two dimensional transmission line simulators.

Measurement of High Frequency Viscoelastic Properties of Deformed Rubber

2016 ◽  
Vol 715 ◽  
pp. 139-146 ◽  
Author(s):  
Tadayoshi Shoyama ◽  
Koji Fujimoto
Keyword(s):  
Resonance Frequency ◽  
High Frequency ◽  
High Speed ◽  
Dynamic Properties ◽  
Loss Modulus ◽  
Low Frequency ◽  
Soft Materials ◽  
Load Cell ◽  
Universal Prediction ◽  
Response Method

Bearings of small turbo machines support high speed rotors rotating with the frequency over 1 [kHz]. Such bearings are often supported with O-rings made of soft materials like rubber to attenuate high frequency oscillations. Dynamic properties of rubber supporters have been measured experimentally for individual dimensions, but the universal prediction of dynamic properties for various frequencies is difficult not only because rubbers exhibit nonlinearity against its strain, but because O-ring supporters deform heterogeneously. For the precise prediction, it is necessary to investigate the viscoelasticity of rubber under various deformations and frequencies. Such properties can be measured by the standard shear vibration non-response method of ISO 6721-6 (JIS K 7244-6). However this is applicable only to low frequency range under 100 [Hz] because of the limitation of resonance frequency of the load cell. In this research, based on BERM (Base Excitation Resonant Mass) method, a new method was developed to measure the complex shear modulus at high frequencies up to 1 [kHz] of rubber sheets under homogeneous shear deformations. In the presented method, the force is calculated from the acceleration of the mass instead of the direct measurement by a load cell. Hence accurate measurement became possible even in the range beyond the resonance frequency of a load cell. The measured shear storage modulus G’ and shear loss modulus G” of deformed rubber were presented.

scholarly journals Wall pressure beneath a transitional hypersonic boundary layer over an inclined straight circular cone

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Siwei Dong ◽  
Jianqiang Chen ◽  
Xianxu Yuan ◽  
Xi Chen ◽  
Guoliang Xu
Keyword(s):  
Boundary Layer ◽  
High Frequency ◽  
High Speed ◽  
Low Frequency ◽  
Axial Direction ◽  
Wall Pressure ◽  
Hypersonic Boundary Layer ◽  
High Frequency Signal ◽  
Local Boundary ◽  
Half Angle

AbstractProperties of wall pressure beneath a transitional hypersonic boundary layer over a 7∘ half-angle blunt cone at angle of attack 6∘ are studied by Direct Numerical Simulation. The wall pressure has two distinct frequency peaks. The low-frequency peak with f≈10−50 kHz is very likely the unsteady crossflow mode based on its convection direction, i.e. along the axial direction and towards the windward symmetry ray. High-frequency peaks are roughly proportional to the local boundary layer thickness. Along the trajectories of stationary crossflow vortices, the location of intense high-frequency wall pressure moves from the bottom of trough where the boundary layer is thin to the bottom of shoulder where the boundary layer is thick. By comparing the pressure field with that inside a high-speed transitional swept-wing boundary layer dominated by the z-type secondary crossflow mode, we found that the high-frequency signal originates from the Mack mode and evolves into the secondary crossflow instability.

scholarly journals Determination of the Fault Zone by the Level of Short-Circuit Currents

2018 ◽  
Vol 61 (5) ◽  
pp. 396-407
Author(s):  
F. A. Romaniuk ◽  
E. V. Buloichyk ◽  
M. A. Shevaldin
Keyword(s):  
Fault Zone ◽  
High Speed ◽  
Computational Experiment ◽  
Fault Location ◽  
Dynamic Properties ◽  
Short Circuit ◽  
Worst Case ◽  
Reliable Determination ◽  
Calculated Distance

The methods of determination the fault zone according to the parameters of the emergency mode, which can be used to improve the performance of technical perfection of current protection lines of distributive 6–10 kV one-way power networks, are considered. The advantage of the algorithm of determination the zones of short circuit (SC) according to the level of emergency currents as compared to the remote unilateral method addressing the parameters of the damaged loop corrupted loops (loops) is noted. Calculation of the estimated distance to the point of SC on the basis of difference of damaged phase currents has been proposed, that enables the independence of the obtained result on the type of the fault. A technique for increasing the reliability of the method for determination the short-circuit zone by the level of emergency currents based on information about the type of damage has also been proposed. The effect of load currents and contact resistances of different levels on the magnitude and nature of the changes in the errors of the calculated distance to the short circuit was investigated by the method of computational experiment. The levels of contact resistances relative to the total resistance of the line depending on the place of SC occurrence are determined that provides reliable determination of the fault zone; it is demonstrated that the nature of their alteration is approximately the same for lines of medium and long length. The expediency of correction of the calculated distance to the fault location in many cases of short circuits through the contact resistance so to improve the protection capacity of the high-speed current protection stage is demonstrated. Based on the results of the computational experiment, correction factors for the correction of the value of the emergency current have been obtained; on the basis of the latter the fault zone is determined. The estimation of efficiency of the proposed method of correction has been carried out; it is shown that its application makes it possible to improve the accuracy of determination the fault zone and to expand the zone of instantaneous shutdown of short circuit. The dynamic properties of the proposed algorithm for different modes of the line operation have been investigated; it is ascertained that, in the worst case, the determination of the short circuit zone for a time not exceeding 27 ms is provided.

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