Longitudinal Vibration Amplitude Research Articles

Longitudinal vibration analysis and active disturbance rejection decoupling control of marine anticorrosive coatings Hybrid Propulsion Screw

The traditional manual methods of mixing paint, the construction process is difficult to ensure the quality and efficiency of the construction due to construction instability and error. To address this issue, we propose a novel approach to automatically mix and discharge marine anti-corrosion coatings using a Hybrid Propulsion Screw. The longitudinal vibration of the Hybrid Propulsion Screw (HPS) during operation is a critical factor that affects the mixing and discharge stability of anti-corrosion coatings. To analyze the vibration characteristics and stability of HPS during operation, we established a three-degree-of-freedom longitudinal vibration model of the HPS using the concentrated mass method and numerically solved it using the Runge-Kutta algorithm, and investigated the effects of external excitation and frequency on the longitudinal vibration of the system. Moreover, to reduce the fatigue damage caused by vibration, we introduced the Active Disturbance Rejection Decoupling Control (ADRDC) considering the nonlinear strong coupling relationship in HPS. And finally, we used the Fibonacci series to adjust the parameters of the Extended State Observer (ESO), and the simulation results demonstrate that our proposed approach is effective for controlling the longitudinal vibration amplitude of the system, which is of great significance for developing efficient and reliable screw stirring devices.

Design and Characterization of Ultrasonic Langevin Transducer 20 kHz Using a Stepped Horn Front-Mass

Ultrasonication is a method that is widely used in various fields. One of its applications is to accelerate the process of homogenization, emulsification, and extraction. In the ultrasonicator system, the transducer is an extremely important device. The resonant frequency, longitudinal vibration amplitude, and electromechanical coupling are the targets in designing an ultrasonic transducer. In this investigation, the main contribution was the development of a simple and effective method for mechanically tuning the resonant frequency of the transducer by adding mass to the front end of the mass or stepped horn. This study also aimed to obtain optimal results by examining the effects of geometric dimensions, bolt prestress, stress distribution, resonant frequency, amplitude, and electrical impedance. The ultrasonic transducer model was designed with a resonant frequency of 20 kHz and simulated using the finite element analysis. The steps involved included calculating the dimensions and geometric structure of the transducer, modeling using the finite-element method, and experimental validation. The simulation results and measurements showed that the series resonant frequency, electrical impedance, and effective electromechanical coupling of the Model-4 transducer 16∙13 mm radiator configuration were 20.15 kHz, 100 Ω, and 0.2229 from the simulation results, and 20.17 kHz, 24.91 Ω, and 0.2033 from the measurement results. A percentage difference, or relative error, of 0.1% was obtained between the simulation and the experimental results for this Model-4 with bolt prestressing at 15 kN.

A novel design of ultrasonic vibration system: asymmetric structure

This paper designs an acoustic system of asymmetrical structure based on the theory of wave. Firstly, the frequency equation of asymmetric structural horn (ASH) was obtained by wave theory, the structural dimension of ASH was calculated based on frequency equation. Then, the influence law of different structural parameters on the resonance frequency and amplification coefficient of ASH was obtained. Simulation results demonstrated that the minimum error of the resonant frequency of the designed horn was 0.16%, and the maximum error was 7.57%. Effect of the change of the horn geometry on the acoustic parameters of the acoustic system was analyzed, and the results manifest that the order of influence on the resonance frequency was , the order of influence on the amplification coefficient was . Finally, the variable horn was processed in segmented and integral two processing methods, and its acoustic performance was tested. Results indicated that the vibration form of the horn output was the vertical vibration accompanied by the slightly curved vibration and the longitudinal vibration amplitude of ASH with resonant frequency of 30–35 kHz can reach 5 . ASH meets the requirements of amplitude in ultrasonic assisted machining and can further expand the application field of ultrasonic machining.

Comparative Analysis of Longitudinal and Transverse Vibration Characteristics of Ocean Mining Pipe

In this paper, the 5000 m mining pipe is taken as the research object, and the transverse and longitudinal vibration laws of the pipe under different working conditions are analyzed. Based on the finite element method (FEM), the pipe is discretized and calculated by the Wilson-θ Wilson - θ integral method; finally, the corresponding vibration laws of the mining pipe are obtained. The research shows that the mining pipe vibration responses are irregular motion, with the obvious oscillation phenomenon, and the overall vibration trend decreases first and then increases from the top to the bottom; the maximum vibration response occurs at the pipe top. Under the same working conditions, increasing the towing velocity will decrease the overall longitudinal vibration amplitude and increase the overall transverse vibration amplitude. While the ore bin weight will increase the longitudinal vibration amplitude and decrease the transverse vibration amplitude, increasing the mining pipe large diameter stepped section length and damping will decrease the longitudinal and transverse vibration simultaneously. When the towing velocity is between 0–2.8 m/s, the longitudinal vibration intensity is large, which is the main vibration mode. When the towing velocity is 2.8 m/s, the critical point is reached, and the longitudinal and transverse vibrations have the same intensity. When the towing velocity is greater than 2.8 m/s, the transverse vibration intensity is gradually greater than the longitudinal vibration intensity; at this time, the control of the transverse vibration should be appropriately increased.

Vibratory Conveying by Harmonic Longitudinal and Polyharmonic Normal Vibrations of Inclined Conveying Track

Abstract Vibratory conveying of a material point by harmonic longitudinal and polyharmonic normal vibrations of an inclined conveying surface is considered. The dependence of dimensionless conveying velocity—a ratio of velocity to the product of frequency and amplitude of longitudinal vibration—on several dimensionless parameters is investigated in the moving modes without hopping. Maximal conveying velocity is achieved at the certain values of normal vibration amplitudes and phase difference angle between the longitudinal and normal vibrations, which are called optimal. Their values are dependent on two dimensionless parameters: the inclination angle parameter—a ratio of an inclination angle tangent to a frictional coefficient, the intensive vibration coefficient—a ratio of the longitudinal amplitude of vibration to the amplitude of the first harmonic of normal vibration and frictional coefficient. In a condition of the intensive longitudinal vibration, when its amplitude significantly greater than amplitudes of normal vibration, dimensionless velocity is almost independent of the intensive vibration parameter and it depends only on inclination angle parameter, i.e., on inclination angle and frictional coefficient. The optimal values of harmonics’ amplitudes of polyharmonic normal vibration are determined in dependence of inclination angle parameter with the number of harmonics from 2 to 7. The graphs of considered dependencies are presented and the most important values of parameters are presented in the table. Conclusions are made to determine the optimal vibration parameters and the problems of further research are indicated. The considered vibrations can be used in different vibratory conveying devices with electromagnetic drives.

Dynamic Characteristics of Downhole Bit Load and Analysis of Conversion Efficiency of Drill String Vibration Energy

The longitudinal vibration of the drill pipe contains considerable energy which can be used to improve the rock-breaking efficiency during drilling. It is very important to the development of drilling speed-up tools to have a comprehensive understanding of the energy conversion efficiency of downhole drill string vibration. In this paper, the characteristics of downhole bit load and longitudinal vibration of drill string under different conditions were studied in the experiment, and the analysis method of energy conversion efficiency from drill string vibration to spring potential energy was proposed. The experimental analysis showed that the fluctuation of the downhole bit load was reduced by 10%–90% after the spring was installed in the bottom hole assembly. The rotation rate and the spring elastic stiffness had a significant and positive influence on the fluctuation amplitude of the downhole bit load. Meanwhile, the longitudinal vibration amplitude and acceleration of the drill string peaked at the elastic stiffness of 1 kN/mm. The closer the spring position to the drill bit was, the more severe the longitudinal vibration of the drill string above the spring component was. The bit load and the rotation rate had a positive influence on the severity of longitudinal vibration. The analysis of energy conversion efficiency showed that the available mechanical energy range of the longitudinal vibration of the drill pipe was about 200–420 kW. The work power of the drill string vibration to the spring component increased sharply and then decreased with the increasing of elastic stiffness. The energy conversion efficiency came to the optimal value when the elastic stiffness was between 1 kN/mm and 2 kN/mm. Increasing the rotation rate, keeping the bit load below 134.5 kN and installing the spring component near the drill bit are beneficial for improving the energy conversion efficiency of drill string vibration. This paper reveals the main factors affecting the energy conversion efficiency of drill string vibration and their influencing laws, and determines the range of WOB, rotation speed, spring position and stiffness to obtain the best energy conversion efficiency.

Analysis of Vibration Monitoring Data of Flexible Suspension Lifting Structure Based on Time-Varying Theory

An elevator is a typical flexible lifting machine. In order to monitor the vibration of elevator structure, the vibration characteristics of an elevator with a traction ratio of 1:1 has been tested experimentally. Sensors were arranged on the platform frame, car roof, and hoist rope to test the vibrations of the elevator in both ascending and descending conditions. The transverse, longitudinal, and coupled transverse-longitudinal vibrations were compared and analyzed. Further, the short-time Fourier transform (STFT) method was used to examine the power spectral density (PSD) of the test results, and the main frequency distribution and influencing factors of the vibration of elevator components were investigated. The results revealed that the transverse and longitudinal vibrations of the platform frame were low-frequency vibrations, which was attributed to the elastic interaction between the platform frame and the car frame. The form and amplitude of longitudinal vibration of the car frame were basically consistent with those of the platform frame, but PSD of the transverse vibration had an obvious peak in the high-frequency region. The transverse and longitudinal vibration frequencies of the hoist rope were higher. Furthermore, the peak PSD value of transverse vibration of the hoist rope was 421 times larger than that of the car frame, so a small disturbance at the end of the rope could lead to a huge disturbance in the center of the rope. Overall, this study provides useful insights on designing an elevator monitoring sensor and relevant data processing.

Analysis and Research on Longitudinal Vibration Characteristics of Deep Sea Mining Pipe Based on Finite Element Method

This paper aimed to study the longitudinal vibration characteristics of the 5000 m mining pipe in the ocean under different working wind conditions, offset angle, damping, and ore bin weight. Based on the finite element method, the mining pipe is simplified into beam element and discretized, and the physical and mathematical models of the mining pipe system are established. The Wilson-θ direct integral method is adopted for numerical calculation. The results show that the longitudinal vibration of the mining pipe is irregular, which presents the phenomenon of oscillation. The vibration amplitude decreases first and then increases from top to bottom, the minimum vibration amplitude appears at 1000 m, and the maximum vibration amplitude appears at the top of the mining pipe. Under the same working wind condition, the overall longitudinal vibration amplitude of the mining pipe can be increased by increasing the ore bin weight and the offset angle, but neither of them can change the frequency of the longitudinal vibration. The closer the excitation frequency generated by different working wind conditions is to the natural frequency, the larger the mining pipe longitudinal vibration amplitude is. The closer the vibration frequency generated by the same excitation frequency is to the natural frequency, the stronger the vibration intensity is, and when damping is added, the vibration intensity decreases faster.

Modeling and Dynamic Behavior Analysis of Rope-Guided Traction System with Terminal Tension Acting on Compensating Rope

Traction systems are a good choice for high-rise lift systems, especially in deep wells. With increasing lift depth and weight, rope-guided traction systems have become an essential design methodology in the mine lift field. In this paper, a comprehensive mathematical model is established to simulate the dynamical responses of a rope-guided traction system with different terminal tensions acting on the compensating rope. The results and analysis presented in this paper reveal dynamical responses in terms of longitudinal and transverse vibration. Additionally, a wide range of resonances occurs in the target system. Differences in the dynamical responses between a traditional traction system and tensioned traction system are analysed in detail. Through comparison and analysis, it is determined that terminal tension plays an important role in the suppression of longitudinal vibration in a system. However, changes in the amplitude of longitudinal vibration are independent of terminal tension, which only affects longitudinal elastic elongation and does not affect the basic shape of longitudinal and transverse vibrations. Based on this analysis, it can be concluded that longitudinal vibration suppression can be achieved by applying proper tension on the compensating rope to ensure that it reaches a tensioning state. Continuing to increase terminal tension is not beneficial for the vibration suppression of a system. The results presented in this paper will serve as a valuable guide for the design and optimisation of traction systems.

A low-frequency longitudinal vibration transducer with a helical slot structure.

In this paper, the authors design a longitudinal vibration transducer with a low resonance frequency and a large longitudinal amplitude by carving helical slots on the surface of the hollow cylinder front mass. The resonance frequency of the transducer is calculated by frequency equations obtained from the equivalent circuit of the transducer. A finite element model (FEM) of the transducer is set up, and it is used to compute the admittance and the longitudinal vibration amplitude of the transducer. The influences of the slot number, the width of the slot, the number of spires of the spring, and the helix pitch on the performance of the transducer are analyzed by numerical simulation. The simulation results show that the resonance frequency of the transducer with helical slots is much lower than that of the transducer without slots. A prototype transducer with helical slots is constructed, and the admittance and longitudinal vibration amplitude are measured experimentally. The measured resonance frequency of the transducer is in good agreement with the simulation results. The measured longitudinal vibration amplitude is lower than that computed by the FEM, which may be due to the damping of the materials.

Faraday Waves-Based Integrated Ultrasonic Micro-Droplet Generator and Applications.

An in-depth review on a new ultrasonic micro-droplet generator which utilizes megahertz (MHz) Faraday waves excited by silicon-based multiple Fourier horn ultrasonic nozzles (MFHUNs) and its potential applications is presented. The new droplet generator has demonstrated capability for producing micro droplets of controllable size and size distribution and desirable throughput at very low electrical drive power. For comparison, the serious deficiencies of current commercial droplet generators (nebulizers) and the other ultrasonic droplet generators explored in recent years are first discussed. The architecture, working principle, simulation, and design of the multiple Fourier horns (MFH) in resonance aimed at the amplified longitudinal vibration amplitude on the end face of nozzle tip, and the fabrication and characterization of the nozzles are then described in detail. Subsequently, a linear theory on the temporal instability of Faraday waves on a liquid layer resting on the planar end face of the MFHUN and the detailed experimental verifications are presented. The linear theory serves to elucidate the dynamics of droplet ejection from the free liquid surface and predict the vibration amplitude onset threshold for droplet ejection and the droplet diameters. A battery-run pocket-size clogging-free integrated micro droplet generator realized using the MFHUN is then described. The subsequent report on the successful nebulization of a variety of commercial pulmonary medicines against common diseases and on the experimental antidote solutions to cyanide poisoning using the new droplet generator serves to support its imminent application to inhalation drug delivery.

Kinematics Analysis on Ultrasonic Deep Rolling with Longitudinal-Torsional Vibration

The kinematics model was built based on the principle of ultrasonic deep rolling (UDR) with longitudinal-torsional vibration (LTV), and the trajectory equations of any particles on edge of the roller involved in the process were given; the influences of vibration parameters including phase angle, frequency of LTV, amplitude of longitudinal vibration, amplitude ratio and the rolling process parameters including roller radius, rolling depth, feed rate, the rotation frequency of roller on the trajectory, acoustic system design and processing quality were discussed. The results can provide theoretical basis for the design of acoustic system and optimization of process parameters.

The use of D-optimal design for modeling and analyzing the vibration and surface roughness in the precision turning with a diamond cutting tool

Using a diamond cutting tool in the precision turning process, the vibration of tool-tip has an undesirable effect on the machined surface’s quality. The objective of this paper is to present the mathematical models for modeling and analyzing the vibration and surface roughness in the precision turning with a diamond cutting tool. Machining parameters including the spindle speed, feed rate and cutting depth were chosen as numerical factor, and the status of lubrication was regarded as the categorical factor. An experimental plan of a four-factor’s (three numerical plus one categorical) D-optimal design based on the response surface methodology was employed to carry out the experimental study. A micro-cutting test is conducted to visualize the effect of vibration of tool-tip on the performance of surface roughness. With the experimental values up to a 95% confidence interval, it is fairly well for the experimental results to present the mathematical models of the vibration and surface roughness. Results show that the spindle speed and the feed rate have the greatest influence on the longitudinal vibration amplitude, and the feed rate and the cutting depth play major roles for the transverse vibration amplitude. As the spindle speed increases, the overall vibration of tool-tip tends to more stable condition which leads to the results of the best machined surface. The effects of the feed rate and cutting depth provide the reinforcement on the overall vibration to cause the unstability of cutting process and exhibit the result of the worst machined surface.

Analysis of Longitudinal Vibration of Wheel Set during Locomotive Slippage

Roll-slip oscillation in locomotive is an unstable vehicle motion and it turns into strong self-excited torsional vibration of drives and is usually associated with a negative slop of adhesion curve. The periodic variation of adhesion coefficient between wheel and rail arises and it provokes longitudinal vibration of wheel set. A simplified mathematical model of single wheel-set drive system of locomotive whose rotary and longitudinal freedoms are taken into account is established. The phase trajectory of longitudinal vibration of wheel-set is drawn by numerical simulation and frequencies of vibrations are calculated on the condition that the mean creep ratio exceeds critical creep ratio. The formed mechanics of longitudinal vibration makes clear with help of graphical analysis. Results demonstrate that the longitudinal vibration is self-excited vibration during locomotive slippage. The longitudinal vibration frequency is integral multiple of nature frequency of torsion vibration and the amplitude of longitudinal vibration is the biggest when it is two times. Therefore, parameters such as longitudinal locating stiffness of wheel set should be set rationally to avoid strong longitudinal vibration of wheel set during slippage.

High-frequency, silicon-based ultrasonic nozzles using multiple Fourier horns

This paper presents the design, simulation, and characterization of microfabricated 0.5 MHz, silicon-based, ultrasonic nozzles. Each nozzle is made of a piezoelectric drive section and a silicon resonator consisting of multiple Fourier horns, each with half wavelength design and twice amplitude magnification. Results of finite element three-dimensional (3-D) simulation using a commercial program predicted existence of one resonant frequency of pure longitudinal vibration. Both impedance analysis and measurement of longitudinal vibration confirmed the simulation results with one pure longitudinal vibration mode at the resonant frequency in excellent agreement with the design value. Furthermore, at the resonant frequency, the measured longitudinal vibration amplitude at the nozzle tip increases as the number of Fourier horns (n) increases in good agreement with the theoretical values of 2(n). Using this design, very high vibration amplitude gain at the nozzle tip can be achieved with no reduction in the tip cross-sectional area for contact of liquid to be atomized. Therefore, the required electric drive power should be drastically reduced, decreasing the likelihood of transducer failure in ultrasonic atomization.

Eggshell Cutter Using Ultrasonic Vibration

An eggshell cutting apparatus which utilizes ultrasonic vibration was developed, replacing the conventional apparatus which uses an air cutter, to cut eggshells at the blunt end of eggs. Two ultrasonic vibration sources were used: one with longitudinal vibration only and the other with torsional vibration plus longitudinal vibration. Eggshell cutting experiments using these vibration sources were conducted. The eggshell cutting time sharply decreased with increasing longitudinal vibration amplitude as well as increasing input power. When the source with torsional vibration plus longitudinal vibration was used and the amplitude of longitudinal vibration was 12 µm or less, the torsional vibration was effective for cutting eggshells. Furthermore, at the same input power, the eggshell cutting time by the source with longitudinal vibration only was shorter than that by the source with torsional vibration plus longitudinal vibration. When an egg was cut using the apparatus, there was essentially no cutting noise and the cut surface was smooth.

Anterior clinoidectomy and opening of the internal auditory canal using an ultrasonic bone curette.

During cranial base surgery, use of a high-speed drill for osteotomy has become common. We performed anterior clinoidectomy and opening of the internal auditory canal using an ultrasonic bone curette, and we report the advantages and clinical applications of this method. The ultrasonic surgical equipment comprises a power supply unit, footswitch, and handpiece (weight, 110 g; diameter, 20 mm; length, 140 mm from tip to angled section). The handpiece tip is 2 mm wide, and the amplitude of longitudinal vibration can be varied from 120 to 365 microm at an ultrasonic frequency of 25 kHz. Cool-controlled irrigation fluid emerges near the tip, through the sheath. We performed anterior clinoidectomy in eight cases of paraclinoid aneurysm and opening of the internal auditory canal in six cases of acoustic neuroma without damage to the dura mater or nearby structures such as brain tissue, blood vessels, and cranial nerves. In addition, no damage to the facial nerve or labyrinthine organ resulted from heat or vibration caused by the ultrasonic bone curette. Ultrasonic bone curettage represents safe instrumentation for performance of anterior clinoidectomy and opening of the internal auditory canal without damage to surrounding structures. This technique allows surgeons to perform procedures on deep areas without incurring psychomotor stress.

Characterization of 0.5 MHz Silicon-Based Ultrasonic Nozzles Using Multiple Fourier Horns

ABSTARCTThis paper presents the experimental results of impedance analysis and longitudinal vibration measurement of micro-fabricated 0.5 MHz silicon-based ultrasonic nozzles. Each nozzle is made of a piezoelectric drive section and a silicon-resonator consisting of multiple Fourier horns each with half wavelength design and twice amplitude magnification. The experimental results verified the simulation prediction of one pure longitudinal vibration mode at the resonant frequency in excellent agreement with the design value. Furthermore, at the resonant frequency, the measured longitudinal vibration amplitude gain at the nozzle tip increases as the number of Fourier horns (n) increases in good agreement with the theoretical value of 2n. Using this design, very high vibration amplitude at the nozzle tip can be achieved with no reduction in the tip cross sectional area. Therefore, the required electric drive power should be drastically reduced, decreasing the likelihood of transducer failure in ultrasonic atomization.