Vibration Direction Angle Research Articles

Regularities of particle motion on vibrating conveyor

Vibratory conveying equipment is widely used in industry and agriculture. The choice of operating parameters has a significant influence on the conveying velocity. Herein, the velocity of a particle under equal vibration intensity conditions is investigated using a frequency-adjustable vibratory feeder. The discrete element method was used to study the motion regularities of a particle on a vibrating conveyor. The effects of the amplitude, vibration direction angle, inclination angle, and vibration intensity on the transport velocity of the vibrating conveyor were investigated using the response surface method. The experimental and calculate results demonstrate that the simulation method and the model is reliable. When the vibration intensity is greater than Kc and remains constant, increasing the amplitude increases the velocity of particle motion. A large vibration direction angle enhances the throwing motion of the particle. A large inclination angle enhances the sliding motion. The inclination angle is used to increase transport velocity by enhancing forward sliding and attenuating backward sliding. The response surface analysis shows that the particle motion velocity is more evidently influenced by the amplitude, followed by the installation inclination and vibration direction angles. The results of the study are important for optimizing the design and operating parameters of vibratory conveying equipment.

Study on the screening performance and parameter optimization of linear vibrating screen under the influence of sieve plate airflow

Screening is an important step in the preparation of machine made sand, and the screening performance of the screening machine is the key to improving the production efficiency and quality of machine made sand. This article first explores the influence of airflow generated by sieve plate vibration on particle motion on the sieve through numerical simulation, and verifies the reliability of the simulation model through experimental prototypes. Then, based on the CFD-DEM coupling model, the relationship between screening parameters and screening performance was studied. Finally, based on the screening results and the BP neural network optimized by the sparrow search algorithm, an evaluation model for screening parameters and screening performance was established, and a multi-objective genetic algorithm was used to optimize the high-performance screening parameter combination scheme. The comprehensive optimal performance parameters were obtained: vibration frequency of 15.5885 Hz, amplitude of 2.3789 mm, vibration direction angle of 50.5227, sieve obliquity of 16.6676, and feed rate of 20921 pieces/s.

Discrete element simulation study on the screening effect of composite vibrating screen for coal particles

ABSTRACT To strengthen the layering effect of coal particles on the screen surface and improve the screening efficiency, a composite vibrating screen was proposed based on the void filling effect of mixed particles under vibration and the Lissajous vibration synthesis theory, and the theoretical basis and working principle of the composite vibrating screen were described. The Taguchi orthogonal experiment was designed with the composite, linear, elliptical, and circular vibrating screens as the object, and frequency, amplitude, and vibration direction angle as the variables, wherein the discrete element simulation of the traditional vibrating screen and the composite vibrating screen was conducted, and the comparison results showed that the composite vibrating screen was of great advantage in both screening efficiency and material processing. On the basis of the traditional vibrating screen, the composite vibrating screen further imposed on the particles an exciting force along the width of the screen surface, so that the particles were subject to the effect of exciting force in the xyz three directions; as a result, more diversified force to the particles, more loose mixed particle system, greater activity degree and better layering effect were realized, and then the composite vibrating screen can achieve a more ideal screening effect.

Parameterization of Multi-Angle Shaker Based on PSO-BP Neural Network

It was possible to conduct a study on the shape and parameterization of the vibrating screen so as to explore the relationship between detailed vibrating screen motion parameters and particle group distribution under different screen surface states. The motion characteristics of particle groups in various scenes were investigated, screening performance of vibrating screen with complex parameters was studied, interaction between motion parameters of screen surface and motion of material groups in multi-component mixed particle groups was analyzed, segregation distribution law of multi-component mixed material groups was revealed, and this study presents simulation findings based on the discrete element program EDEM. The ensemble learning approach was used to examine the optimized model screen. It was revealed that the screen’s amplitude, vibration frequency, vibration direction angle, swing frequency, swing angle, and change rate of screen surface inclination all had a major impact on its performance. As a result, the vibrating screen’s running state was described by various parameter combinations, and the trend changes of several factors that affected the performance of the screen were examined. The investigation revealed that the particle swarm optimization backpropagation (PSO-BP) neural network model outperformed the backpropagation (BP) neural network model alone in terms of prediction. It had lower root mean square error (RMSE), mean square relative error (MSRE), mean absolute error (MAE), and mean absolute relative error (MARE) than the BP neural network model, but a larger R2. This model’s greatest absolute error was 0.0772, and its maximum relative error was 0.0241. The regression coefficient R value of 0.9859, which displayed the model’s strong performance and high prediction accuracy, showed that the PSO-BP model was feasible and helpful for parameter optimization design of vibrating screens.

Study on Screening Parameter Optimization of Wet Sand and Gravel Particles Using the GWO-SVR Algorithm

The optimization of screening parameters will directly improve the screening performance of vibration screens, which has been a concern of the industry. In this work, the discrete element model of wet sand and gravel particles is established, and the vibration screening process is simulated using the discrete element method (DEM). The screening efficiency and time are used as evaluation indices, and the screening parameters including amplitude, vibration frequency, vibration direction angle, screen surface inclination, the long and short half-axis ratio of the track, feeding rate, and screen surface length are investigated. The results of an orthogonal experiment and range analysis show that the amplitude, screen surface inclination, and vibration frequency are significant factors affecting screening performance. Then, the support vector regression optimized with the grey wolf optimizer (GWO-SVR) algorithm is used to model the screening data. The screening model with excellent learning and prediction ability is obtained with the Gaussian kernel function setting. Moreover, the GWO-SVR algorithm is used to optimize the screening parameters, and the screening parameters with optimal screening efficiency and time are obtained. Furthermore, the effectiveness and reliability of the optimized model are verified using the discrete element calculation. The optimization strategy proposed in this work could provide guidance for the structural design of vibration screens and screening process optimization.

Design and optimization of a tea vibrating-shifting machinery

ABSTRACT Tea screening is a key process in the tea refining and processing industry. However, the tea shakers which are key components in tea screening have low screening efficiencies, and there is a lack of research on the optimization of key factors affecting the same. In this study, a tea vibrating-shifting machine driven by an eccentric wheel-linkage was designed. The force and motion process of tea particles were theoretically analyzed, and the dynamic equation of the tea particles was deduced. For improving the screening efficiency of the tea vibrating-shifting machine, the experimental prototype was optimized with the screening efficiency as the objective function. Additionally, a quadratic orthogonal test of response surface was established using a commercial software. The analysis of variance indicated the following parameters affecting the screening efficiency in decreasing order of influence: vibration direction angle, eccentric wheel angular velocity, and sieve mesh inclination angle. As per the optimization results of regression equation, for a vibration direction angle of 21.68°, the sieve mesh inclination angle was 2.95°, the eccentric wheel angular velocity was 25.24 rad/s, and the maximum screening efficiency was 86.24%.

Study on Migration Law of Solid Particles on Sieve Surface of Solid-liquid Separator

Based on the discrete element method and the three-dimensional discrete element analysis software EDEM, simplify the tube net type solid liquid separator model, to explore the net type solid liquid separator inside the cylindrical screen opaque screen the migration law of solid phase particles and different vibration frequency, vibration amplitude, vibration direction Angle, diameter of sieve sieve speed and sieve cylinder is opaque screen the influence of solid phase particles migration rule, In order to provide reference for the selection of structural parameters and vibration parameters of solid-liquid separator in field application. The results show that the motion trajectory of solid particles on the screen is a three-dimensional spiral curve. The larger the vibration frequency and amplitude of the screen box, the higher the particle migration speed. The larger the vibration direction Angle, diameter and speed of sieve box, the smaller the particle migration speed. The research results can be used for reference in the selection of structural parameters and motor vibration parameters that affect the comprehensive performance of the cylinder net solid-liquid separator.

Parameter optimization and mechanism research of double-layer variable screen surface vibrating screen

In the vibrating screening operation, each area of the screen surface has a different screening environment, and the material layer thickness, target particle proportion and other parameters of each area are different, which limits the screening efficiency of a vibrating screen with a traditional screen surface. In this paper, a double-deck variable screen surface screening method is proposed to optimize the design of the double-deck screen surface. The relationship between the elements of the screening process, screening parameters and screening efficiency of a double-deck variable screen surface vibrating screen is investigated through DEM numerical simulation. Using the particle swarm algorithm to support the vector regression model for global optimization, the parameters of the double-deck variable screen surface vibrating screen further optimized to obtain screening parameters: screen area A screen hole edge length of 4.7 mm, screen area D screen hole edge length of 2.7 mm, screen area D screen surface inclination angle of 6.3°, amplitude 2.6 mm, vibration frequency of 22.2 Hz, vibration direction angle of 35°, and through the experimental prototype for physical experimental verification.

The Nonlinear Dynamic Behavior of a Particle on a Vibrating Screen Based on the Elastoplastic Contact Model

The dynamic response of particles is closely related to screening efficiency. To study the dynamic response of particles, the dynamic equations of a particle on a screening surface are established based on the elastoplastic contact model of spherical particles and are solved for the coal particle. Then, the trajectories of the particles are given with different falling heights and particle radii. The completely different trajectories with slight changes in the falling height and particle radius indicate strong nonlinearity. Second, the nonlinear dynamic behavior under different amplitudes and frequencies is discussed, and the route of transition from quasiperiodic motion to chaotic motion is revealed. Finally, we discuss the average speed along the screening surface considering the frequency, amplitude, friction coefficient, inclination angle, and vibration direction angle. In addition, the convergence conditions of particle motion are proposed, and they are only affected by the inclination angle and friction angle. The results show that in the normal direction of the vibrating screen, the particle motion is quasiperiodic at low frequencies. With increasing frequency, the motion of the particle becomes chaotic, and its Poincaré map becomes petal-shaped. In addition, the number of petals increases at the mutation of the bifurcation diagram. The increase in frequency, amplitude and inclination angle and the decrease in friction coefficient lead to an increase in particle speed along the screen surface. In addition, the particle speed reaches a maximum when the vibration direction angle is 65°. This work provides a theoretical basis for controlling the thickness of granular material flow on a vibrating screen and selecting screening process parameters.

Numerical Investigation of the Vibration of a Circular Cylinder in Oscillatory Flow in Oblique Directions

The response of an elastically mounted circular cylinder vibrating in an oscillatory flow oblique to the flow direction is investigated. Simulations are conducted for vibration angles ranging from 0° to 90°, with 0° and 90° corresponding to the cases where the vibration is inline and perpendicular to the flow direction, respectively. One mass ratio of 2, one Reynolds number of 150, and two Keulegan–Carpenter (KC) numbers of 5 and 10 and a wide range of frequency ratios that cover the lock-in regime are considered. The frequency ratio is the ratio of the oscillatory flow frequency to the natural frequency. The maximum vibration amplitude is highest when the cylinder vibrates in the flow direction (vibration angle = 0°) and gradually decreases with the increase of the vibration direction. All the identified flow regimes are mapped on the frequency ratio versus vibration angle space. In addition to the flow regimes that exist for a stationary cylinder, two variants of Regime F (F1 and F2), a new flow regime R and an unstable regime D/F are found. The vortex street directions of Regime F1 and F2 are the opposite to and the same as the direction of the vibration, respectively, Regime R is a regime where a dominant vortex circles around the cylinder and Regime D/F is an unstable regime where the flow changes between Regime D and F frequently. The contribution of the higher harmonics in the vibration increases with the increase of the vibration direction angle. As a result of the strong contribution of higher harmonics at large vibration angles and small frequency ratios, local peak values of the vibration amplitude are found at frequency ratios of 0.4 and 0.25 for KC = 5 and 10, respectively.

Optimization Research on Screening Parameters of Elliptical Vibrating Screen Based on DEM Theory

Most of the vibrating screens pay too much attention to the screening efficiency and neglect the material transportation speed in the research process, so this paper introduces W to comprehensively consider the influence of screening efficiency and material transportation speed, and optimizes the vibration parameters of the vibrating screen based on the GRNN-PSO model. This optimization method is more accurate and effective than the previous method used to optimize the parameters of the vibrating screen. First, numerical simulation of the screening process based on EDEM software was carried out, and the influence of vibration frequency, amplitude and direction angle of vibration on the screening efficiency and material transportation speed was studied. The orthogonal experiment was further constructed, and the GRNN model between each vibration parameter and W was established based on the orthogonal experiment data and the single factor experiment data. Then, using the established GRNN model as the fitness function, the vibration parameters were optimized by the PSO algorithm, and the obtained optimized parameters were substituted into the simulation model, which further proved the accuracy and effectiveness of the GRNN-PSO model. This research helps understand the combined effect of various vibration parameters and provides a reference for the vibrating screen's efficient operation and parameter design.

Study on screening performance and parameter optimization of vibrating-dewatering screen

In this paper, the dewatering and screening process of vibrating-dewatering screen is studied by the combination of simulation test and physical experiment. The simulation model of dewatering screening process is established by the method of computational fluid dynamics (CFD) and discrete element method (DEM). Subsequently, the screening efficiency and processing efficiency are defined as evaluating indexes for performance of dewatering and screening. Four parameters of amplitude, vibration frequency, vibrating direction angle and slope angle of screen surface are selected for single factor simulation test, and the variation of dewatering and screening performance under different parameters is obtained. Finally, the reliability of the simulation results is verified by the physical experiment platform, and significant factors affecting the evaluation index of the vibrating-dewatering screen parameters and the optimal parameter combination are obtained by orthogonal test.

Effect of Vibration Direction of Ultrasonic Vibrating Cutting Edge on Internal Stress Fluctuation of Workpiece

The aim of this study is to investigate the dynamic phenomenon of ultrasonic vibration-assisted cutting by utilizing a stress distribution visualization system. The vibrating cutting-edge is considered to be a cause of dynamic changes in the cutting force at ultrasonic frequencies. However, many researchers have explained the effect of ultrasonic vibration-assisted cutting by evaluating the time-averaged cutting force, because existing dynamometers are unable to measure the dynamically changing cutting force at ultrasonic frequencies. There are some reports that the vibration direction of cutting edge strongly affects tool wear. However, in practical ultrasonic cutting, the vibration of the cutting edge has yet to be measured in a production environment. In this study, the instantaneous stress distribution on the workpiece was visualized by a photoelastic method that combines a pulsed laser emission synchronized with tool vibration. The developed photographic system can capture 360 frames in one ultrasonic vibration period. The dynamic cutting force was calculated by Flamant’s stress distribution theory. It was experimentally confirmed that the stress distribution under vibration-assisted conditions showed periodical changes synchronized with vibration. Because these results are compatible with well-known vibration-cutting theories, the imaging system was able to show the periodic changes in stress distribution in the ultrasonic frequency band. This indicates that the dynamic change in cutting force during the ultrasonic vibration period affects intermittent cutting conditions. In this report, the vibration direction was adjusted from −9.5° to +9.5° along the cutting direction. When the tool moved in upwards for the cutting phase and downwards for withdrawal phase, the stress distribution was continuously observed over one tool vibration period; no intermittent cutting was observed. The locus of the cutting force vector was affected by the ultrasonic vibration direction and rake angle of the cutting tool. A negative rake angle showed that the direction of the cutting force vector shifted toward the workpiece side near the most advanced position of the cutting edge.

Multiple parameter collaborative optimization of a particle separation equipment for coal cleaning production

Vibrating screens represent an effective particle separation equipment for coal cleaning. During the screening process, critical particles block the screen holes, and affect the screening performance. Therefore, a vibrating screen with a higher inclination angle and larger screen pore has been proposed to prevent plugging of the screen surface. In this work, a screening model for the vibrating screen was established based on the discrete element method. The screening process was simulated, and the screening efficiency could be obtained. Through single factor tests, the influence of the amplitude (A), frequency (f), and vibration direction angle (β) on the screening efficiency was analyzed. The results show that, upon increasing A, f, and β, the screening efficiency first increases and then decreases. It was found that an improved screening effect can be achieved when A, f, and β are 3–4 mm, 12–14 Hz, and 35–45°, respectively. A mathematical model describing the effect of A, f, and β on the screening efficiency was implemented based on the response surface methodology, and the degree of influence of each parameter on the screening efficiency resulted to be in the following order: A > f > β. The highest screening efficiency (81.4%) was obtained under optimized conditions, with the relevant parameters being A = 3.7 mm, f = 13.4 Hz, and β = 40.9°. The results indicate that the optimization scheme is feasible and reliable.

Performance optimization of the elliptically vibrating screen with a hybrid MACO-GBDT algorithm

As a typical screening apparatus, the elliptically vibrating screen was extensively employed for the size classification of granular materials. Unremitting efforts have been paid on the improvement of sieving performance, but the optimization problem was still perplexing the researchers due to the complexity of sieving process. In the present paper, the sieving process of elliptically vibrating screen was numerically simulated based on the Discrete Element Method (DEM). The production quality and the processing capacity of vibrating screen were measured by the screening efficiency and the screening time, respectively. The sieving parameters including the length of semi-major axis, the length ratio of two semi-axes, the vibration frequency, the inclination angle, the vibration direction angle and the motion direction of screen deck were investigated. Firstly, the Gradient Boosting Decision Trees (GBDT) algorithm was adopted in the modelling task of screening data. The trained prediction models with sufficient generalization performance were obtained, and the relative importance of six parameters for both the screening indexes was revealed. After that, a hybrid MACO-GBDT algorithm based on the Ant Colony Optimization (ACO) was proposed for optimizing the sieving performance of vibrating screen. Both the single objective optimization of screening efficiency and the stepwise optimization of screening results were conducted. Ultimately, the reliability of the MACO-GBDT algorithm were examined by the numerical experiments. The optimization strategy provided in this work would be helpful for the parameter design and the performance improvement of vibrating screens.

Numerical Investigation on the Sieving Performance of Elliptical Vibrating Screen

Screening techniques have been widely deployed in industrial production for the size-separation of granular materials such as coal. The elliptical vibrating screen has been regarded as an excellent screening apparatus in terms of its high screening efficiency and large processing capacity. However, its fundamental mechanisms and operational principles remain poorly understood. In this paper, the sieving process of an elliptical vibrating screen was numerically simulated based on the discrete element method (DEM), and an approach coupling the DEM and the finite element method (DEM–FEM) was introduced to further explore the collision impact of materials on the screen deck. The screening time, screening efficiency, maximum stress and maximum deformation were examined for the evaluation of sieving performance. The effects of six parameters—length of the semi-major axis, length ratio between two semi-axes, vibration frequency, inclination angle, vibration direction angle and vibration direction—on different sieving results were systematically investigated in univariate and multivariate experiments. Additionally, the relationships among the four performance indexes were discussed and the relational functions were obtained. The conclusions and methodologies presented in this work could be of great significance for the design and improvement of elliptical vibrating screens.

A new study on dynamic adjustment of vibration direction angle for dual-motor-driven vibrating screen

For a dual-motor-driven elliptical vibrating screen, the driving frequencies of the two motors are studied in this paper and it exposes the significant influences of different driving frequencies on the vibration direction angle of the self-synchronous system. A dynamic model is established to demonstrate the new concepts and innovative ideas put forth in this paper. Simulink and prototype experiments are implemented to further study the influences of different driving frequencies on the phase angle and the vibration direction angle. The results of simulation and experiments shows that vibrating screen driven by the two motors can not only achieve a stable synchronization within a certain frequency range by changing the driving frequency of either of the two motors, but also the vibration direction angle significantly changes at similar but different driving frequencies. This is an important finding that has important significance for the future operations of dual-motor-driven vibrating screen in industry. The method developed in this study would be a valuable engineering tool which can be used in design and application of the screens and the screening operations.

Particle stratification of a vibrating screen with translation-swing composite motion

With the development of science and technology, more and more demand was proposed in the sieving industry. The sieving theory has been used to optimize parameters of vibrating screen to achieve a higher screening efficiency. Perfecting the sieving theory was became the main goal of most scholars to study the vibrating screen. Stratification as part of sieving theory research, the screening process and screening result was deeply influenced by stratification. In this paper, the sedimentation difference was defined to make the stratification became a numerical description. The discrete element method (DEM) has been used to simulate the screening process about the vibrating screen with translation-swing composite motion. The relationship between screening efficiency and sedimentation difference under each parameter is established and the effect of stratification on screening efficiency is studied under various single parameter conditions including vibration frequency, amplitude, vibration direction angle, swinging frequency, and swinging angle. The conclusions are: sedimentation difference is closely related to screening efficiency, the screening efficiency had obviously a positive correlation with the sedimentation difference. Combined with the value of the sedimentation difference, a better positive stratification is meaningful to the screening process and screening efficiency.

Research on impact characteristics of screening coals on vibrating screen based on discrete-finite element method

ABSTRACTScreening is used extensively for the size classification of coals. During the screening process, the impact of oversized material often causes damage to the screen surface, which then affects the reliability of the vibrating screen. In this study, an orthogonal experiment was designed, and the influence of vibration parameters on impact force was determined using range and variance analysis. The analysis results indicate that the impact force decreases as the amplitude, frequency, and inclination angle increase, and increases as the vibration direction angle increases. The effect of each factor on the impact force within the level range is in the decreasing order: inclination angle, vibration direction angle, frequency, and amplitude. The influence of inclination angle on the impact force is highly significant, vibration direction angle is significant, while the frequency and amplitude are not significant. Therefore, increasing amplitude and decreasing vibration direction angle are the effective ways to reduce the impact force. In order to determine the response of the screen surface under impact, data coupling of discrete-finite element method (DEM-FEM) was performed, and the stress and deformation of the screen surface under a full load were obtained. The results show that the areas of highest stress and largest deformation of the screen surface are mainly located at the blanking position and discharge end. According to the analysis of the DEM-FEM results, the arrangement of the supporting beams was optimized. Compared with a traditional uniform arrangement, the maximum stress of the screen surface decreases by 2.884%, the maximum deformation decreases by 55.952%, the bearing of the screen surface is more uniform and reasonable, and these provide reference points for the design of a vibrating screen.

Performance optimization of banana vibrating screens based on PSO-SVR under DEM simulations

This paper carried out the numerical simulation about the movement of non-spherical particles on banana vibrating screen using direct element method (DEM) considering the complexity of particle collision and avoiding obtaining motion information with difficulty. Experimental prototype of banana vibrating screen under variable parameters was manufactured to verify the feasibility of simulations. Because the complex non-linear mathematical model is the basis of optimization. Based on the simulation data this paper applied the least squares support vector machines (LS-SVM) to establish relationships between vibrating parameters of banana screen and screening performance. LS-SVM based on statistical theory can effectively solve the mapping problem of small sample. At same time, in order to improving the quality of modeling, the kernel parameters of SVM were optimized by particle swarm optimization (PSO). Considering multi-extremum, large-scale, and non-differentiable of this computational model, the artificial fish-swarm algorithm (AFSA) with strong robustness and global convergence was applied to vibration parameters optimization. Finally, the optimal vibration parameters were: vibration amplitude 2.4 mm, vibration frequency 21 Hz, vibration direction angle 40 degrees.