Vibration Speed Research Articles

A new control method of rotor re-suspension after short failure of active magnetic bearing system

As it is difficult for traditional control method to realize rotor resuspension after short failure of Active Magnetic Bearing (AMB) system, a new control method containing rotor collision force evaluation algorithm module, rotor position control algorithm module and rotor vibration speed control algorithm module was proposed. Through the evaluation of rotor collision force, the controller automatically selects rotor positon control mode or rotor speed control mode. Based on rigid rotor theory, rotor dynamic model was established to analyze the dynamic responses after short failure of AMB system utilizing different control method. The results proved that the proposed control method can successfully realize rotor re-suspension.

Numerical analysis of vibration-isolating effect of vibration-isolating slot under buried pipe subjected to millisecond blasting

Research on vibration-isolating effects of vibration-isolating slot on buried pipe can be done by numerical method, without being disturbed by external environmental factors. It has measured data without relatively high experiment cost and analyzed the influence of some key parameters according to the results of numerical simulation. The results show that the vibration speed of the pipeline with vibration-isolating slot tends to have a larger decrease than those without vibration-isolating slot. What’s more, the homogeneous explosive charge is discrepant in different working conditions, but the vibration-isolating ratio is similar in the vibration-isolating slot with same structure parameter. The millisecond blasting is hardly affected by total explosive charge. But the blasting seismic intensity is influenced by explosive charge in each stage directly.

Numerical simulation on fracture mechanics behavior of high-pressure gas pipeline

The numerical simulation could help to understand the fracture mechanics behavior of high-pressure gas pipeline. The calculation results show that the internal high pressure of gas provides a driving force for crack propagation and tube wall deformation when the pipeline cracks and expands. Therefore, the rapid crack propagation tends to occur when the steel pipe is driven by high-pressure gas. In the process of steel pipe crack extension, immense internal high-pressure gas spewed from rupture and expand rapidly, compressing the air to form a series of compression wave which propagate rapidly and superpose together to form a shock wave eventually. Because the explosive wave of the pipe rupture has a high directivity, the energy distribution of gas is not uniform during the releasing process. What’s more, in pipe blasting, the longer distance, the more the surface vibration velocity decreases. In the vicinity of explosion source, the decreasing trend of the peak vibration velocity is significant. The vertical vibration velocity at the same point is larger than the longitudinal and tangential vibration speed.

Вибрации ползуна при токарной обработке

Computation dependences on the definition of vibration amplitude in machine sliding blocks of a lathe group, in particular, sliding blocks of boring lathes of VM series, feed through cutters and boring ones are defined. Vibration speeds of oscillations in the direction of coordinate axes with the aid of which one defines actually amplitudes of deformations are defined. As a result of investigations there are determined dependences to obtain amplitudes of deformations, mean-square values of oscillation speeds affecting errors at parts machining on boring lathes.

Its own spectrum band - a property of mechanical systems

In experimentally and modelling, the results have been obtained, revealing the existence of the hardes tmode of broadband random vibration in function of the spectral width when it impacts on the mechanical system. During broadband random vibration there are extremums of tension in the material and vibration speed during the capture of «n» original frequencies of the system (n≥2). This fact indicates on presence of the “own bands” of the mechanical system, similar to the natural frequencies, but which appears at random loading.

A field study of terrain effect for periodic vibrating-taking the ground vibration induced by road roller as an example

Taking vibration wave induced by road roller as a research object, terrain effect characteristics in propagation of periodic vibration wave were studied through the ground vibration monitoring. Data analysis results show that, vibration distance, frequency and terrain condition were the main factors affecting the attenuation speed of the ground vibration. On the flat terrain, the ground vibration velocity attenuated in negative exponential function form with distance; In complex terrain condition, the attenuation characteristic changed. Vibration velocity was obviously amplified when the location of the measuring point is higher than the source, and decreased more rapidly at the lower place. The increase of vibration frequency enhanced the topographic effect, the amplification of ground vibration caused by higher frequency vibration was more pronounced. The mathematical model of periodic vibration wave attenuation was proposed according to the characteristics of vibration velocity. The model provided an effective reference for the calculation of the safety distance which took the frequency, the height difference and the distance into account.

Influence of vibration in cutting on tool flank wear: Fundamental study by conducting a cutting experiment with forced vibration in the depth-of-cut direction

In this research, we developed special vibration tools, in which a simple harmonic vibration is generated with controlled frequency and amplitude, and experimentally clarified the influence of vibration in cutting on the tool flank wear. The results of the tool wear experiment show that the wear increasing rate (increment in the flank wear width with respect to the cutting length) increases depending on the vibration speed, whereas wear is not affected by the frequency if the vibration speed is the same. Moreover, the observations reveal that the tool flank face interferes with the workpiece as the vibration speed increases, thereby increasing the abrasive wear.

Effects of corrosion-inhibiting surface treatments on irradiated microstructure development in Ni-base alloy 718

The objective of this study is to understand the influence of surface treatments, namely laser shock peening (LSP) and ultrasonic nanocrystal surface modification (UNSM), on the irradiation tolerance of a Ni-base alloy. Surface treatments such as LSP and UNSM have been shown to mitigate the potential for primary water stress corrosion cracking (PWSCC). As such, there is emerging interest in the development and implementation of LSP and UNSM for nuclear reactor components. The LSP process utilizes a laser-generated plasma, while UNSM utilizes mechanical contact at ultrasonic vibration speeds, to create near-surface compressive residual stresses, high dislocation densities, twins and subgrains, and nanostructuring of the workpiece. These resultant microstructural changes can substantially affect the creation and evolution of irradiation damage. Herein, we study precipitation hardened Ni-base Alloy 718+, which is utilized in reactor components exposed to PWSCC-inciting environments. Specimens are treated with LSP or UNSM, then irradiated with 2.0 MeV protons to 7 displacements per atom (dpa) at 500°C. The dislocation line density is roughly an order of magnitude larger in the unirradiated LSP and UNSM specimens than in the baseline (untreated) specimen. Irradiation-induced dislocation loop nucleation results in an increase in the areal density of dislocation-type defects. Irradiation also induces disordering of the γ′ precipitates; this disordering appears more extensive in the baseline than in the LSP and UNSM specimens. Results are considered in the context of overall sink strength. Finally, irradiation-induced softening is observed in all specimens through nanoindentation, and is ascribed to the overall change in sink strength, resulting from the competition between γ′ disordering and dislocation loop nucleation.

Методика оцінювання технічного стану насосних агрегатів за рівнями вібрації та показниками енергоефективності

The purpose. To develop a technique of assessment of technical condition of pump units (PU) according to the levels of vibration and indexes of power efficiency which will enable in due time to determine time of holding engineering service and major overhaul of pump-power facilities of pumping stations (PS) of irrigation systems in conditions of their exploitation. To carry out analysis of results of on-site investigations of PS gained at power diagnostic studies and vibration monitoring. To determine correlation between vibration and its influence on use reliability and power efficiency of PU. Methods. Information-analytical — for the analysis and assessment of domestic and foreign proceedings on the yielded theme; experimental — for determination of power characteristics and levels of vibration of PU with application of modern means of measurement technology and vibration monitoring; statistical and system approaches — mfor the analysis and processing experimental data. Results. Data gained at on-site investigations of PS of irrigation systems are analyzed. Scientific-methodological approach is offered to assessment of technical condition of PS according to the levels of vibration and indexes of power efficiency, based on a hypothesis about correlation between indexes of vibration (vibration speed and vibration acceleration) and aberration of coefficient of performance (CP) of PU. Conclusions. Necessity is proved of perfecting technique of holding power diagnostic studies of PU with assessment of technical condition of PS according to the levels of vibration which will enable objectively assess technical condition of pump-power facilities of PS of irrigation systems.

Initiating predictive maintenance for a conveyor motor in a bottling plant using industry 4.0 concepts

For the past recent years, Industry 4.0 (I40) also known as smart manufacturing, together with advanced manufacturing techniques, has been introduced in the industrial manufacturing sector to improve and stabilize processes. Nevertheless, practical applications of these advanced technologies are still in their early stages resulting in slow adoption of the I40 concepts, especially for small- to medium-scale enterprises (SMEs). This paper proposes the design of an experimental method to integrate the practical use of Industry 4.0 in a small bottling plant; especially by detecting early faults or threats in conveyor motors and generating accordingly a predictive maintenance schedule. Using advanced programming functions of a Siemens S7-1200 programmable logic controller (PLC) controlling the bottling plant, vibration speed data is monitored through vibration sensors mounted on the motor and an efficient predictive maintenance plan is generated. The running PLC communicates with a supervisory control and data acquisition (SCADA) graphical user interface (GUI) which instantaneously displays maintenance schedules and allows, whenever required, flexible configuration of new maintenance rules. This paper also proposes a decentralized monitoring system from which vibration speed states can be monitored on a cloud-based report accessible via the Internet; the decentralized monitoring system also sends instant email notifications to the intended supervisor for every maintenance schedule generated. By its results, this research shows different possibilities of the practical use of Industry 4.0 basic concepts to better manufacturing operations within SMEs and opens a path for more improvement in this sector.

Ultrasonically assisted bone drilling—effect of process parameters on delamination

ABSTRACTBone drilling is a crucial operation in orthopedic, maxillofacial, and trauma surgery. Delamination is a familiar defect in the drilling process and can seriously disrupt postoperative regeneration near the implant site in bone surgery. This research experimentally investigates the problem of delamination around drilled holes in vibration-assisted drilling of in cortical bone on the delamination around drill holes in cortical bone. Drilling speed and amplitude of vibration were found to have almost no influence on delamination, while higher feed rate was found to moderately increase delamination. Highest reduction in delamination was found to occur at higher frequencies of vibration imposed on the drill in the feed direction. Statistical analysis (ANOVA) also indicated that delamination is most significantly affected by frequency of drilling, only slightly by feed rate, and almost negligibly by drill speed. Overall, it can be concluded that ultrasonically assisted drilling, with an appropriately selected frequency and feed rate, would yield far lower amount of bone delamination than conventional drilling. Results from this work can be useful for researchers and practitioners in the fields of biomechanics and orthopedic surgery.

Monitoreo de Condición en Motores de Combustión Interna Monocilíndricos con Base en Adquisición y Procesamiento de Señales Experimentales

In recent years, condition monitoring based on signal analysis has become a valuable tool for the diagnosis of internal combustion engines. In this paper the experimental design for the ICE monitoring condition, based on signal analysis, is presented. The experimental configuration was development for the analysis of signals from ICE in order to monitor their condition. The conduced case study consists on the monitoring condition of a single-cylinder engine, operating under regular conditions and different speeds. The instrumentation, the adquisition systems as well as the signals analysis are also presented. The adquired signals were: engine block vibration, in-cylinder pressure and crankshaft speed. The mentioned signals were analyzed and processed by FFT and Rigid Regression. It was possible to obtain the frequency spectrum of the vibration signal and reconstruct the in-cylinder pressure of the single-cylinder engine. The presented configuration can be taken as a basis for the evaluation of others engines and for improving the schemes of monitoring condition.Keywords: Internal combustion engines, condition monitoring, signal acquisition, signal processing.

Controlled Double-Jet Mixing of Light Speeds in the Trigonometric Realm

We were inspired by three great concepts: 1. Pythagorean means, 2. Pierre de Fermat´s principle of the least time, 3. Michael Faraday´s concept of vibrating rays in longitudinal and transverse directions. We have formulated an extended Doppler formula for rectilinear motions in the absolute spacetime where both postulates of the special relativity are valid. The second postulate of the special relativity for rectilinear motions was derived as the harmonic mean speed based on the Pythagoras-Fermat-Faraday (PF2) model. The null result of the Michelson-Morley experiment is valid for the arms of that interferometer separated by the angle π/2. However, for the angles smaller than π/2 a predicted fringe shift should be observed. For the circular motions the Doppler formula combines the longitudinal and transverse speeds in such a way that the frequency of the rotating light beam is diluted by a factor [1-(v/c)2]0.5 and the wavelength of that light beam is extended by the same factor. The Doppler formula for light beams can be tested for the rotating source and the detector placed close to the rim of that rotating disk in a defined position. In order to obtain new experimental data we propose to construct the Michelson-Morley-Harress-Sagnac interferometer where rotating disks have being attached to both arms of the Michelson interferometer. In rotating disks we might prepare light beams with defined independent values of their longitudinal speeds and after the mixing of these two light beams on their return path to the detector we might observe predicted fringe shifts. In these circular paths the second postulate of the special relativity is not valid. The full composition of Doppler formula is given by the interplay of the macro Doppler effect (the relative motion of the source and observer) and the micro Doppler effect (the combination of the longitudinal and transverse vibration speeds of that oscillating particle – the elasticity of the photon wave).

Ultrasonic Cutting of Switchgrass and Miscanthus Stems

Abstract. Ultrasound-assisted cutting has been used to cut materials with high precision, improved quality and reduced cutting forces. The research objective was to investigate the effects of high-frequency vibrations on the cutting force and cutting energy of switchgrass and miscanthus stems. Laboratory experiments were conducted on individual biomass stems at cutting speeds between 3 and 400 mm/s. An experimental cutting system with an ultrasound generator, an ultrasonic blade, a load cell, and a data acquisition system was developed. The custom designed blade was 5-cm wide and vibrated at 19.551 kHz with 2.8 µm tip vibration amplitude. There were significant measured differences in the cutting forces and cutting energies between conventional cutting and ultrasonic cutting of switchgrass and miscanthus stems (p < 0.05). These results suggest that the use of high-frequency vibrations reduce cutting force and cutting energy of both switchgrass and miscanthus stems. Ultrasound-assisted cutting reduced the cutting energy of switchgrass by 66.85% at 100 mm/s and miscanthus by 80.58% at 30 mm/s. However, ultrasonic cutting did not have a significant effect on the cutting force and cutting energy when the cutting speed was equal to or greater than the blade tip vibration speed. The results of this research should be useful for adapting the ultrasonic technology in biomass harvesting, particle size reduction, and processing equipment. Keywords: Biomass, Blades, Energy, Finite element analysis, Miscanthus, Switchgrass, Ultrasonics.

Quenching of light flickering in synthetic guanine crystals in aqueous solutions under strong static magnetic fields

The present study focused on the vibration of micro crystal particles of guanine due to Brownian motion. The organic particle has a refractive index of 1.83 and caused a flickering of light. To test the possibility of using magnetic properties under wet conditions, changes in the frequency of particle vibration by applying magnetic fields were investigated. At first, we found that the exposure at 5 T inhibited the flickering light intensities and the particle vibration slightly decreased. Next, we carried out a high speed camera measurement of the Brownian motion of the particle with a time resolution of 100 flame per second (fps) with and without magnetic field exposures. It was revealed that the vibrational speed of synthetic particles was enhanced at 500 mT. Detailed analyses of the particle vibration by changing the direction of magnetic fields versus the light source revealed that the Brownian motion’s vibrational frequency was entrained under magnetic fields at 500 mT, and an increase in vibration speed to 20Hz was observed. Additional measurements of light scattering fluctuation using photo-detector and analyses on auto-correlation also confirmed this speculation. The studied Brownian vibration may be influenced by the change in mechanical interactions between the vibration particles and surrounding medium. The discovered phenomena can be applied for molecular and biological interactions in future studies.

Surfactant-enhanced PEG-4000-NZVI for remediating trichloroethylene-contaminated soil

In this study a NZVI was prepared by the liquid phase reduction method. The modified NZVI obtained was characterized by BET, TEM and XRD. The results showed that the iron in the PEG-4000 modified material is mainly zero-valent iron with a stable crystal structure. It has a uniform particle size, ranging from 20 to 80 nm, and a larger specific surface area than CTAB modified NZVI, SDS modified NZVI and commercial zero-valent iron. The two surfactants CTAB and SDS are also selected as solubilizers, the results showed that the two selected surfactants obviously solubilize trichloroethylene in soil. Compared with commercial zero-valent iron, PEG-4000 modified NZVI is better removed trichloroethylene from soil; Also, the optimal operational parameters were obtained. When the experimental conditions were: PEG-4000 modified NZVI dosage 1.0 g/L, CTAB/SDS concentration equal to the CMC, SDS concentration was 2.0 × CMC, CTAB was concentration 1.0 × CMC and the vibration speed 150 r/min, the removal efficiency of trichloroethylene in a soil-water system reached 100% after 4 h. Both NZVI combined with CTAB and NZVI combined with SDS followed fitted first order reaction kinetics during the removal of trichloroethylene and their reaction rate constant k was 0.6869 mg/(L·h) and 0.5659 mg/(L·h), respectively. According to the chloride ion detection test, the trichloroethylene degradation is mainly due to reductive dechlorination.

Quantum Metric of Classic Physics

By methods of differential geometry and number theory the following has been established: All fundamental physical constants are the medians of quasi-harmonic functions of relative space and relative time. Basic quantum units are, in fact, the gradients of normal distribution of standing waves between the points of pulsating spherical spiral, which are determined only by functional bonds of transcendental numbers PI and E. Analytically obtained values of rotational speed, translational velocity, vibrational speed, background temperature and molar mass give the possibility to evaluate all basic quantum units with practically unlimited accuracy. Metric of quantum physics really is two-dimensional image of motion of waves in three-dimensional space. Standard physical model is correct, but SI metric system is insufficiently exact at submillimeter distances.

Analysis on the Factors of Surface Morphologies on Si<sub>3</sub>N<sub>4</sub> Ceramic Internal Grinding

Different grinding parameters of silicon nitride ceramic are researched at the process of internal grinding. The influences on the roughness of surface by the linear speed of grinding wheel (vs), radial feeding speed (f) and axial vibration speed (fa) are studied in the uniformity testing. The experimental equation of silicon nitride ceramic internal grinding is optimized. The machined surface morphologies of the ceramic specimen are measured by roughness instrument of Taylor-Hobson Surtroni-25 and scanning electron microscope of S-4800. The results show that with the increasing of the linear speed of grinding wheel the roughness of surface get reduced, and with the increasing of radial feeding speed the roughness of surface get raised. It is also inversely proportional to the axial vibration speed. The linear speed of grinding wheel has the biggest impact on the roughness of surface of the silicon nitride ceramic internal grinding among the three grinding parameters. With the increasing of linear speed of grinding wheel, the value of roughness of surface declines from 0.4095μm to 0.1726μm. The influences on the roughness of surface of the silicon nitride ceramic internal grinding by different factors are found out in the research, and its removal mechanisms are cleared up under different linear speeds of grinding wheel.

Design and performance optimization of gravity tables using a combined CFD-DEM framework

In this paper we formulate a computational framework for the characterization and performance optimization of gravity tables. Segregation of a multi-dispersed population of grains is assessed using a comprehensive numerical framework integrating Computational Fluid Dynamics (CFD) simulations with a Discrete Element Method (DEM) setup in the open-source software OpenFOAM. We have carried out combined qualitative and quantitative assessments of process conditions, such as deck shape, deck inclination (longitudinal and transverse), vibration speed and fluidizing air velocities at the surface. We assess the performance of our framework by employing a quantitative metric rhostat, which represents the efficiency of separation in terms of density differences between the two separated product fractions. Additionally, qualitative flow behaviour is evaluated by examining relevant velocity and material distribution trends. We show that these separation profiles are highly sensitive to changes in the process conditions, with the presence of discernible optimal operating points. For the chosen gravity table, we have identified a longitudinal tilt of 6°, an eccentric speed between 300 and 350RPM, deck air velocities of up to 1.5m/s and a transverse tilt of 0.75° as a set of optimal operating conditions.

Confocal Surface Plasmon Embedded Interferometric Microscope: A Brief Review

In this paper, we firstly explain the concept of surface plasmon resonance imaging and a main key issue in the field of localized SPR imaging, which is the trade-off between resolution and sensitivity. We will then explain how V(z) scanning confocal microscope can overcome the trade-off and enable us to make a localized detection of multiple analytes in small quantities. This paper provides a brief review on a chronological development of the confocal surface plasmon embedded interferometric microscope and highlights the key idea behind each developments. Theoretical detection limit of the confocal system is within a single molecule detection regime, where 100kD molecule can be detected with 100μJ of light in the confocal system. We also discuss some key challenges in achieving the theoretical limit, such as, microphonic vibration and slow scanning speed of the system and how to get around these challenges. Lastly, we discuss some possible future developments to improve the system.