Vibration Speed Research Articles

Monitoring of wind effects on a wind-sensitive hybrid structure with single-layer cable-net curtain walls under Typhoon Muifa

As a new type of building structure, the single-layer cable net (SL cable net) is widely used in many large landmark buildings with modern glass curtain walls. As a kind of wind-sensitive structure, the wind effects on the SL cable net is a problem that cannot be ignored. Therefore, a field measurement was carried out at the China Maritime Museum during Typhoon Muifa. The wind field characteristics and the wind-induced dynamic responses of the SL cable net during this typhoon were well studied. The relationship between the wind characteristics and the dynamic characteristics was analyzed. It was found that the vibration intensity of the SL cable net, unlike that of high-rise buildings, is not correlated with the time-varying mean but is positively correlated with the fluctuating wind speed. By using the method SSI and NExT, it was found that the low-order frequencies of the SL cable net are insensitive to the time-varying mean but have a negative correlation with the RMS fluctuating wind speed. The vibration of the SL cable net was proved to be a more direct cause of the phenomenon of frequency softening. Reasons of this phenomenon were discussed in this paper. At last, damping ratios of the SL cable net were studied and found to be insensitive to the structural vibration or wind speed in this paper.

Liquid CO2 Phase Change Fracturing and Vibration Monitoring in Roadbed Slope Excavation

In order to analyze the vibration impact of carbon dioxide fracturing tube blasting red sandstone, combined with the engineering conditions and surrounding environment of Anqing High-tech Zone, the rock-breaking blasting plan is carefully designed. The fracturing tube is arranged in two rows, the first row has 23 holes with a spacing of 1.5m, and the second batch of holes has 22 holes, which are arranged in a quincunx pattern with a distance of ‘1.3m between the front and rear rows. And design the corresponding vibration signal monitoring test to study the crack propagation caused by blasting, the attenuation law of vibration and its frequency spectrum distribution. The results show that after blasting, there is a relatively smooth crack in the plane area of the fracture zone 7m away from the critical surface. The width of the crack is between 20-40cm. The vibration velocity of the measuring point decays rapidly with the increase of the vibration source distance, and the vibration velocity decay curves in the X and Y directions are basically the same. Spectrum analysis shows that the main frequency band of each sub-velocity is generally below 100Hz, and the main vibration frequencies in the X and Y directions are concentrated in 30∼60Hz. The main vibration frequency band of the rock-breaking blasting vibration signal has little correlation with the direction and propagation distance of the vibration signal. And compared with the analysis of emulsion explosives, it is found that the particle vibration speed caused by the emulsion explosive rock-breaking blasting is much greater than that of the liquid CO2 fracturing tube rock-breaking blasting, indicating that the use of liquid carbon dioxide to break the rock can effectively reduce the vibration generated by blasting.

Planetary gearbox fault diagnosis using bidirectional-convolutional LSTM networks

Gearbox fault diagnosis is expected to significantly improve the reliability, safety and efficiency of power transmission systems. However, planetary gearbox fault diagnosis remains a challenge due to complex responses caused by multiple planetary gears. Model-based gearbox fault diagnosis techniques extract hand-crafted features from sensor data based on underlying physics and statistical analysis, which are not effective in extracting spatial and temporal features automatically. While deep learning methods such as convolutional neural network (CNN) enable automatic feature extraction from multiple sensor sources, they are not capable of extracting spatial and temporal features simultaneously without losing critical feature information. To address this issue, we introduce a novel deep neural network based on bidirectional-convolutional long short-term memory (BiConvLSTM) networks to determine the type, location, and direction of planetary gearbox faults by extracting spatial and temporal features from both vibration and rotational speed measurements automatically and simultaneously. In particular, a CNN determines spatial correlations between two measurements within one time step automatically by combining signals collected from three accelerometers and one tachometer. Long short-term memory (LSTM) networks identify temporal dependencies between two adjacent time steps. By replacing input-to-state and state-to-state operations in the LSTM cell with convolutional operations, the BiConvLSTM can learn spatial correlations and temporal dependencies without losing critical features. Experimental results have shown that the BiConvLSTM network can detect the type, location, and direction of gearbox faults with higher accuracy than conventional deep learning approaches such as CNN, LSTM, and CNN-LSTM.

Dynamic stability/instability simulation of the rotary size-dependent functionally graded microsystem

In the current paper, vibrational and critical circular speed characteristics of a functionally graded (FG) rotary microdisk is examined considering a continuum nonlocal model called modified couple stress (MCS) model, for the first time in the literature. The generalized differential quadrature (GDQ) approach and variational method are used for deriving and solving the non-classical final relations. The FG size-dependent micro-sized disk’s final relations and corresponding boundary conditions (BCs) are achieved on the basis of the higher-order shear deformation (HSD) model. Then, a parametric analysis has been conducted to analyze the influences of the length scale factor, circumferential, radius ratio and radial mode number, FG material’s configuration, and BCs on the FG micro-scaled disk’s frequency by taking into account the MCST. The outcomes reveal that, at the initial value of the FG index (β), the negative impact from rotating speed on the dynamic stability of the system becomes bold. Furthermore, at the β factor’s lower amount and spinning velocity’s higher amount, there is instability in the responses of the system. Additionally, it is indicated that the negative effect from radius ratio on the frequency responses of the rotary FG microdisk becomes considerable at the length scale factor’s higher amount.

Development of a vibration monitoring system for rotating machine models using fast fourier transform

Judul: Pengembangan sistem pemantauan getaran untuk model mesin berputar menggunakan fast fourier transform Title: Development of a vibration monitoring system for rotating machine models using fast Fourier transform Sering kali terjadi kerusakan mekanis pada mesin silinder berputar . Kerusakan itu terjadi akibat dari getaran yang terjadi pada mesin-mesin berputar. Penyebab getaran pada mesin berputar antara lain disebabkan oleh beberapa hal di antaranya: ketidakseimbangan, tidak sejajar, dan bagian yang tidak sempurna atau cacat pada komponen mesin. Penelitian ini mencoba untuk memberikan solusi dengan cara pendekatan analitik menggunakan sistem pemantau getaran. Sistem tersebut bisa memberikan manfaat dalam proses deteksi, memvisualisasi getaran dalam bentuk grafis, menemukan magnitudo yang merupakan puncak getaran dan menghitung frekuensi getarnya. Pada penelitian ini dikembangkan prototipe alat pemantau getaran dengan melengkapi komponen Load cell sebagai sensor getar, arduino atmega 2560 untuk sistem kontrol, dan mengimplementasikan fast fourier transform. The spinning cylinder engine is often damaged mechanically. Vibrations in spinning machinery cause damage. The reasons for vibration in rotating machines include imbalance, misalignment, and faulty parts or faults in machine components. This research attempts to offer a solution by using an analytical method and a vibration monitoring system. The system may help with the detection process, displaying vibrations in graphic form, determining the amplitude and peak of the vibration, and computing the vibration frequency. In this research, a prototype of a vibration monitoring device was created by completing the load cell component as a vibration sensor, Arduino Atmega 2560 for the control system, and applying fast fourier transform.

Multi-chord IR-visible two-color interferometer on KSTAR.

Major parts of an IR-visible two-color interferometer (TCI) on KSTAR have been upgraded for the multi-chord operation: (1) a diode-pumped-solid-state (DPSS) laser (660nm) replacing the former HeNe laser (633nm), (2) vacuum-compatible vibration isolator with titanium retro-reflectors, and (3) full digital phase comparator for multi-chord real-time density signals. The commercial compact DPSS laser suits the multiple chord configuration with its strong beam power (500 mW) and long coherent length (>100 m). Ti retro-reflectors are mounted on vacuum-compatible vibration isolators. The isolators are essential for the visible beams to avoid any fringe skips due to their short wavelength, considering the speed of the mechanical vibration (up to hundreds of μm). Field-programmable-gate-array (FPGA) modules count the entire fringes fast enough with a signal output rate up to 1.25MHz, solving the fringe skip issues. The FPGA module enables the full digital processing of the phase comparator with a CORDIC algorithm after the sampling rate of 160 MS/s for the 40MHz intermediate frequency of each beam. The full digital signals are transferred to the main plasma control system in real-time. Stable single-input-single-output operation of the KSTAR density control was demonstrated with the TCI. The real-time density profile control is also promising in the near future, with multiple actuators such as pellets and gas puffings.

Influence of Unit Length on Pavement Roughness Evaluation Results Based on Driving Vibration Data

The method of evaluating pavement roughness with vibration acceleration data collected by smart phones is influenced by many factors, of which the length of pavement evaluation unit is an important one. In order to explore the influence of evaluation unit length on pavement roughness evaluation result with vibration data, this paper carried out a driving experiment, used the self-developed smart-phone APP acquisition running-vehicle vibration of data, used the multi-function checkout automobile detection of pavement smoothness, and established the relationship models of pavement roughness — vibration index and speed index when the evaluation unit length are 100 m, 500 m and 1000 m respectively. The results showed that when the unit length is 1000 m, the accuracy of the evaluation model is the highest, and the determination coefficient reaches 0.876. The verification experiment also proved that the evaluation model has good accuracy and stability. And also it was showed that the accuracy of the pavement roughness evaluation model increases with the increase of the length of the evaluation unit, which may be related to the matching error between the vibration data and the pavement roughness. How to improve the accuracy of the evaluation results about the short unit is the key content to be studied in the future.

Wear Mechanism and Failure Analysis of A High-speed Train Hydraulic Damper Using CFD Approach

To evaluate wear-induced hydraulic damper failures, wear mechanism of a Chinese CRH train hydraulic damper by invaded dust and sand particles under vibration conditions is firstly analysed, CFD modelling of the working chamber of the damper is then carried out and fluid dynamics analysis of the damper under different vibration speed input conditions is performed. The CFD results demonstrate that under wear conditions both the fluid discharge speed and produced pressure would drop significantly, the maximum fluid discharge speed and pressure are far smaller than that under non-wear conditions, the damping force would have a maximum decrease of 62.3%. The wear mechanism, CFD model established and analysis results obtained in this study can be used for further railway hydraulic damper evaluation and optimal designs.

Analysis of the Influence of Underground Traffic Tunnels by the Explosion Seismic Effect of the Storage Yard

The dynamic response of the existing deep underground traffic tunnel under the seismic effect of dangerous goods explosion is an important issue that should be actively considered before the construction of the container yard. In order to ensure the safety of the tunnel, this paper first introduces the goods to be stored in the newly built container yard of dangerous goods and their dangerous characteristics. Then, the vibration response of the tunnel wall under the explosion of 1 t, 2.6 t and 6 t TNT is simulated by using Midas GTS finite element analysis software. When the explosive equivalent is 2.6 t, the vibration speed of the tunnel wall is in a safety critical state. The simulation results provide reference suggestions for the types of engineering design stockpiles and limited stockpiles and control the influence of dangerous goods container yard on traffic tunnel from the source.

Методика модельного исследования функционирования редуктора

An imitation model of a gear reducer is considered, taking into account its gear ratio, multi-mass, friction, and gearing errors. The structures of individual components and the general model of the reducer is presented. The spectrum of speed fluctuations of the output link of the reducer is obtained and a comparison is made with the spectrum of vibration speed obtained using a vibration analyzer on a real object. The approach proposed in the work makes it possible to establish the nature of the reasons causing the gearbox vibration.

Utilization of field seismometers for measuring the paraseismic vibrations of mining blasts

The Hrabuvka Quarry was one of the quarries on which the seismic effects were measured when performing large-scale blasting operations – bench blasting. These measurements were carried out as part of a university project to investigate further unfavourable seismic effects of blasting operations with respect to the type of ignition and explosives used. The aim of this article is to determine whether during the large-scale blasting operations from April to June 2019 vibration speed values were measured, which could have adverse effects on quarry structures and to propose a suitable solution to reduce these values, for example by changing the type of ignition from non-electric to electronic and by changing the ignition timing of individual charges.

Multi-Objective Optimization of Multistage Pump Balance Drum System Based on BP Neural Network and Genetic Algorithm

The axial force balancing capacity of a balance drum is a key factor affecting the life of multi-stage centrifugal pumps. In this paper, a double shell segmental multistage pump is taken as the research object. The hydraulic performance and axial force performance are set as the optimization objectives, and the performance data are obtained by numerical simulation with FLUENT software. The BP neural network is used to establish the prediction model of structural parameters of the balance system, hydraulic performance and residual axial force performance, and it is used as the adaptive value evaluation model of genetic algorithm to solve the optimal value in the sample space. The results show that the radial clearance of the balance drum and the balance tube orifice flowmeter, the axial width of the balance cavity are the significant factors affecting the hydraulic performance and axial force performance of the multistage pump. When the radial clearance of the balance drum is 0.1mm, the clearance of the orifice flowmeter is 1.95mm, and the axial width of the balance cavity is 55mm, the multi-stage pump has the best hydraulic performance and the smallest residual axial force. The vortex band in the balance cavity can increase the amount of the fluid spin and enhance the axial force balancing capacity of the balance drum. The greater the area occupied by the negative high-rotation fluid in the balance cavity, the stronger the ability of the balance drum to balance the axial force. The test results show that compared with the prototype multistage pump, at nominal flow rate, the head and efficiency of the optimized model are increased by 0.71% and 1.63% respectively, and the bearing temperature and vibration speed of the multi-stage pump are significantly reduced.

Multistage pump axial force control and hydraulic performance optimization based on response surface methodology

In order to comprehensively optimize the axial force and hydraulic performance of the multistage pump, considering that there are relatively more secondary impeller stages and the blade profile has a greater impact on the axial force and hydraulic performance, Plackett–Burman test design method in this paper is adopted to conduct significance analysis and screening of the secondary impeller parameters. Based on the response surface methodology, a central composite test is designed for three control variables with strong sensitivity. The multiple regression model between the parameters of the secondary impeller and the hydraulic performance and axial force of the multistage pump is established. The optimal parameter combination which takes the performance and axial force into account is obtained. The accuracy of the optimization results is verified through tests. The results show that the blade exit angle, outlet diameter and blade wrap angle of the secondary impeller have the most significant influence on the axial force and hydraulic performance of the multistage pump. The results of variance analysis and coefficient test show that the regression model is highly significant and can reflect the objective relationship between the control parameters of the secondary impeller shape and the response objectives. A larger outlet diameter and blade wrap angle of the secondary impeller can improve the head of the multistage pump. A larger blade wrap angle and a smaller blade exit angle of the secondary impeller can reduce the axial force of the multistage pump. By solving the multiple regression equation, it is found that when the outlet diameter of the secondary impeller is 292 mm, the blade exit angle is 22°, and the blade wrap angle is 150°, the axial force of the multistage pump is the lowest and the hydraulic performance is slightly improved. It is verified by experiments that the head and efficiency of the optimized multistage pump increase by 0.95% and 1.71%, respectively, the temperature of the front and rear bearings decreases by 16.49% and 16.17%, respectively, and the vibration speed of the multistage pump along three directions is significantly reduced.

A Pot-Like Vibrational Microfluidic Rotational Motor.

Constructing a micro-sized microfluidic motor always involves the problem of how to transfer the mechanical energy out of the motor. The paper presents several experiments with pot-like microfluidic rotational motor structures driven by two perpendicular sine and cosine vibrations with amplitudes around 10 μm in the frequency region from 200 Hz to 500 Hz. The extensive theoretical research based on the mathematical model of the liquid streaming in a pot-like structure was the base for the successful real-life laboratory application of a microfluidic rotational motor. The final microfluidic motor structure allowed transferring the rotational mechanical energy out of the motor with a central axis. The main practical challenge of the research was to find the proper balance between the torque, due to friction in the bearings and the motor’s maximal torque. The presented motor, with sizes 1 mm by 0.6 mm, reached the maximal rotational speed in both directions between −15 rad/s to +14 rad/s, with the estimated maximal torque of 0.1 pNm. The measured frequency characteristics of vibration amplitudes and phase angle between the directions of both vibrational amplitudes and rotational speed of the motor rotor against frequency of vibrations, allowed us to understand how to build the pot-like microfluidic rotational motor.

Surface modeling and analysis of high-speed ultrasonic vibration cutting

High-speed ultrasonic vibration cutting has been proven to be effective in prolonging tool life, as well as reducing cutting force and cutting temperature at certain cutting speeds, which is higher than both the critical cutting speed of traditional ultrasonic vibration cutting and the range of conventional high-speed cutting in recent research. However, the surface topography results from the periodic sinuous tool vibration trajectory, and its influence on machined surface roughness, remains unclear. Therefore, in this article, the modeling and analysis of the surface topography and roughness are developed first. Then, simulations conducted through MATLAB calculations, SOLIDWORKS modeling, and cutting experiments are conducted to investigate the influences of the feed rate and the phase shift between the adjacent tool trajectories on the surface roughness. The results indicate that optimal surface roughness can be obtained under the conditions of a small feed rate (0.005 mm/r) and a phase shift of 180°. In this condition, the surface finish can reach Ra < 0.4 μm and realize finishing machining. In addition, compared with conventional cutting, high-speed ultrasonic vibration cutting can achieve the same quality at a cutting speed two times that of conventional cutting. Consequently, a better surface quality can be obtained through high-speed ultrasonic vibration cutting, due to the decrease of surface roughness compared with that of conventional cutting.

Application of Deep Eutectic Solvents for the Extraction of Carnosic Acid and Carnosol from Sage (Salvia officinalis L.) with Response Surface Methodology Optimization.

Salvia officinalis L. is a good source of antioxidant compounds such as phenolic diterpenes carnosic acid and carnosol. From 17 deep eutectic solvents (DESs) used, choline chloride: lactic acid (1:2 molar ratio) was found to be the most suitable for the extraction of targeted compounds. The influence of H2O content, extraction time, and temperature (for stirring and heating and for ultrasound-assisted extraction (UAE)), H2O content, extraction time, and vibration speed for mechanochemical extraction on the content of targeted compounds were investigated. Carnosic acid content obtained by the extraction assisted by stirring and heating was from 2.55 ± 0.04 to 14.43 ± 0.28 µg mg−1, for UAE it was from 1.62 ± 0.29 to 14.00 ± 0.02 µg mg−1, and for mechanochemical extraction the yield was from 1.80 ± 0.02 to 8.26 ± 0.45 µg mg−1. Determined carnosol content was in the range 0.81 ± 0.01 to 4.83 ± 0.09 µg mg−1 for the extraction with stirring and for UAE it was from 0.56 ± 0.02 to 4.18 ± 0.05 µg mg−1, and for mechanochemical extraction the yield was from 0.57 ± 0.11 to 2.01 ± 0.16 µg mg−1. Optimal extraction conditions determined by response surface methodology (RSM) were in accordance with experimentally demonstrated values. In comparison with previously published or own results using conventional solvents or supercritical CO2, used DES provided more efficient extraction of both targeted compounds.

Assessment of Ballast Flying in the National Railway Network of Ethiopia

One of the major problems in ballasted railroads is ballast flying, which is the projection of ballast particles from the at-rest position as the train passes over the track of a railway structure, mainly due to high speed. In this research, the possibility of railway ballast flying for the double track Addis-Adama section of the new Addis-Djibouti railway line is assessed by determining the major causes of ballast flying and applying Discrete Element Modeling (DEM) with the aid of Particle Flow Code (PFC3D) software. The analysis comprised of an impact load and ballast material behavior which were used to determine the vibrational speed of individual ballast particles. The governing result from the series of discrete element analyses performed by considering fouled ballast gradation with grain-size diameter of 22.4 mm gives rise to a ballast maximum vibrational speed of 0.014 m/s. Since the ballast vibrational speed for Addis Ababa-Adama line is less than 0.02 m/s that is recommended by the literature, no ballast flight is expected under the present traffic and ballast conditions.

Vibration Response Characteristics of Adjacent Tunnels under Different Blasting Schemes

The vibration caused by the tunnel blasting and excavation will harm the surrounding rock and lining structure of the adjacent existing tunnels. This paper takes a two‐lane large‐span highway tunnel as the research object, conducts on‐site monitoring tests on the impact of vibration caused by the blasting and excavation of new tunnels on the existing tunnels under different blasting schemes, and analyses in detail the three‐dimension vibration velocity by different excavation footages. From the vibration speed, it is concluded that the influence of the existing tunnel of the newly built tunnel blasting team is affected by various factors, such as distance, free surface, charge, and blasthole distribution. With different blasting schemes, the greater the amount of charge, the greater the vibration caused by blasting. Existing tunnels correspond to the front of the tunnel, and the axial and radial vibration peaks are greater than the vertical. Although the cut segment uses a less amount of explosive and has a less blasthole layout, there is only one free surface. Because of the clamping of the rock, it is compared with the other two segments. The vibration caused is the largest. Although the peripheral holes are filled with a large amount of explosive, the arrangement of the blast holes is relatively scattered and there are many free surfaces. Hence, the vibration caused is the smallest. Corresponding to the back of the tunnel face, since there is no rock clamp, the vibration caused by the cut segment is the smallest, and the vibration caused by the peripheral segment and the floor segment is relatively large. The vibration caused by the front explosion side is significantly greater than the vibration caused by the back explosion side. The vibration velocity caused by the unit charge of 1.5 m footage is greater than that of the 3.0 m footage. The vibration velocity caused by the unit charge of the cut segment is the largest, and the vibration velocity caused by the peripheral segment and the floor segment is smaller. The research results provide a reference for the blasting control of similar engineering construction.

Design of Intelligent Counting Equipment System for Uniform Materials

In fields such as manufacturing and agriculture, manual methods are generally used to count materials such as hardware parts and seeds, which had problems such as slow speed, low efficiency, and low accuracy, and a lot of pressure was put on people. Based on machine vision and motion control, a uniform material counting equipment system was designed. The equipment uses a two-stage conveyor belt for material transportation, and vibration frequency control and speed control of materials of different specifications were achieved. Because of application of precision motion control technology, the camera collects the image of the material and identifies the material to be inspected, and automatically counts the quantity of the material by calculating the area of the material. The test was implemented with screws, hole gaskets, soy, jujubes and other materials, and the results show that: materials with a size of 2mm-20mm can be detected; the detection accuracy rate is 100%.the system has realized high-speed, high-efficiency, high-accuracy automatic counting, and has good application value.

A New Method for Vibration Suppression of Switched Reluctance Motor Using Liquid Cooling Medium

The vibration problem of a switched reluctance motor (SRM) comes from its structure and operation principle, and seriously affects its application. In fact, the vibration is caused by the radial electromagnetic force of SRM. The electromagnetic field numerical calculation software Magnet can simulate the direction of radial electromagnetic force. In addition, the Maxwell stress method was used to deduce the judgment rule of the direction of radial electromagnetic force in an experiment of measuring the flux distribution of SRM stator model. The finished test results confirmed the calculation results of Magnet software. On this basis, using the pressure of liquid cooling medium to reduce the radial electromagnetic force, a new type of switched reluctance motor stator structure is designed by immersing the whole stator with a moving fluid formed by the evaporative cooling liquid medium. It is proved by ANSYS and ANSYS Workbench software that under the effect of temperature difference, the evaporative cooling medium flows at a certain velocity field which strengthened the liquid pressure and the liquid pressure of the evaporative cooling medium counteract the radial electromagnetic force, and meanwhile weaken the vibration caused by it. As a conclusion, all the simulations show that the new type of SRM stator structure filled with evaporative cooling medium can reduce the SRM stator vibration speed by 40%.