Analysis of vibrations for a vibrating jaw crusher when interacting with material

A model of a vibrating jaw crusher (VJC) with self-synchronizing unbalanced vibration exciters is considered with account of the impacts between the jaws and the material being processed. Numerical modeling is used to establish the influence of the initial gap between the jaws and the material and of the velocity recovery factor upon impact on the synchronization of vibration exciters rotation and jaw vibrations, on the excitation frequency ranges of stable periodic vibroimpact regimes, and on the impact velocities between the jaws. The analysis results indicate that a change in the conditions of contact between the jaws and the material being processed leads to a change in the frequency ranges of the stable antiphase synchronization of vibration exciters rotation, as well as in the excitation frequency ranges of steady single-period vibroimpact regimes for the motion of the system, considered as the main operating modes of the VJC. The impact-like nature of the interaction between the jaws and the material being processed suggests the possible multimodality of the system, which explains some of the effects observed in practice and manifested in changes in the periodicity of the vibroimpact regime and in the vibration mode of the jaws at a constant excitation frequency. Therefore, the vibroimpact-based model proposed for the VJC and its dynamics analysis results may be used to design and improve vibrating jaw crushers with the selection of reasonable design parameters and the most effective vibration excitation conditions. The work was carried out with the financial support of the RFBR, project No. 18-08-01491_a.

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Impact of Cross-Tie Properties on the Modal Behavior of Cable Networks on Cable-Stayed Bridges

The Scientific World JOURNAL ◽

10.1155/2015/989536 ◽

2015 ◽

Vol 2015 ◽

pp. 1-14 ◽

Cited By ~ 3

Author(s):

Javaid Ahmad ◽

Shaohong Cheng ◽

Faouzi Ghrib

Keyword(s):

Analytical Model ◽

Design Parameters ◽

Reference Base ◽

Cable Network ◽

Cable Networks ◽

Modal Behavior ◽

Stiffness And Damping ◽

Main Cables ◽

The Impact ◽

Selection Of

Dynamic behaviour of cable networks is highly dependent on the installation location, stiffness, and damping of cross-ties. Thus, these are the important design parameters for a cable network. While the effects of the former two on the network response have been investigated to some extent in the past, the impact of cross-tie damping has rarely been addressed. To comprehend our knowledge of mechanics associated with cable networks, in the current study, an analytical model of a cable network will be proposed by taking into account both cross-tie stiffness and damping. In addition, the damping property of main cables in the network will also be considered in the formulation. This would allow exploring not only the effectiveness of a cross-tie design on enhancing the in-plane stiffness of a constituted cable network, but also its energy dissipation capacity. The proposed analytical model will be applied to networks with different configurations. The influence of cross-tie stiffness and damping on the modal response of various types of networks will be investigated by using the corresponding undamped rigid cross-tie network as a reference base. Results will provide valuable information on the selection of cross-tie properties to achieve more effective cable vibration control.

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Investigating the effect of vibration on the stability of the three-wheeled scooter taxi

Nigerian Journal of Technology ◽

10.4314/njt.v39i4.19 ◽

2021 ◽

Vol 39 (4) ◽

pp. 1117-1122

Author(s):

S.J. Ojolo ◽

O.O. Ajayi ◽

G.A. Asuelinmen

Keyword(s):

Excitation Frequency ◽

Vehicle Safety ◽

Asian Countries ◽

Wheeled Vehicle ◽

Safety Margins ◽

Schematic Layout ◽

Analysis Design ◽

The Stability ◽

The Impact ◽

Selection Of

The present three wheeled scooter taxi (TWST) that are widespread in Africa and Asian Countries are fuel economical and inexpensive. However, they are unstable due to their schematic layout. This instability places limitation on the usage of the vehicle. Researchers have investigated the rollover and lateral stabilities of this vehicle, including the effect of vibration on the comfort of the riders. However, not much work has been done on the impact of vibration on the stability of the vehicle. These instabilities could be induced by trenches, potholes, uneven and ungraded roads that are prevalent in developing countries. Therefore, this work modelled and analysed the effect of vibration on a TWST using a standard road bump as reference point. The results proved the vehicle to be unstable in the vicinity of excitation frequency of 15.95rad/sec and spring constant of 68,600N/m due to resonance. This would affect safety of life and property. Therefore, it would be appropriate for some of the manufacturers of these vehicles to provide for enough safety margins in the design and selection of springs where the vehicles are rollover and laterally unstable. This will enhance the vehicle safety and receptivity. Keywords: Three wheeled Vehicle, Vibration Modelling and Analysis, Design, Safety of Life and Property

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The Impact of Modelling Air Compressibility in the Selection of Optimal OWC Design Parameters in Site Specific Wave Conditions

Volume 10: Ocean Renewable Energy ◽

10.1115/omae2019-96123 ◽

2019 ◽

Author(s):

Irene Simonetti ◽

Lorenzo Cappietti

Keyword(s):

Fluid Dynamic ◽

Experimental Tests ◽

Design Parameters ◽

Dynamic Simulations ◽

Regression Approach ◽

Wave Conditions ◽

A Site ◽

The Impact ◽

Period Wave ◽

Selection Of

Abstract The importance of properly modelling the effects of air compressibility in the selection of the optimal design parameters for an Oscillating Water Column wave energy converter is investigated. For this purpose, a wide dataset of capture width ratios, obtained from both experimental tests and Computational Fluid Dynamic simulations, is used to formulate an empirical model able to predict the performance of the device as a function of its basic design parameters (chamber width and draught, turbine damping) and of the wave conditions (wave period, wave height). A multiple non-linear regression approach is used to determine the model numerical coefficients. The data used to formulate the model include the effects of air compressibility. The impact of considering such effects on the selection of the optimal geometry of the device is evaluated and discussed by means of the model application for the optimization of a device to be installed in a site located in the Mediterranean Sea (in front of the coast of Tuscany, Italy).

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RESEARCH OF THE IMPACT ON PRODUCTIVITY OF PARAMETERS AND OPERATING MODES OF THE VIBRATION MACHINE DRIVE FOR CLEANING AND WASHING CONTAMINATIONS BY SUBMERGTD STREAM JET WITH SOLID PARTICLES

East European Scientific Journal ◽

10.31618/essa.2782-1994.2021.1.68.13 ◽

2021 ◽

Vol 1 (4(68)) ◽

pp. 46-52

Author(s):

A. Staryi ◽

A. Hordeev

Keyword(s):

Solid Particles ◽

Design Parameters ◽

Specific Method ◽

Vibration Machine ◽

Operating Modes ◽

Machine Drive ◽

Instantaneous Pressure ◽

Machine Parts ◽

Physical Phenomena ◽

The Impact

Analyzed the methods of cleaning and washing, the design of machines with a vibration drive. The choice of a specific method of cleaning and washing is determined depending on the type and properties of contaminants, on the requirements for the cleanliness of products, and the type of production. The scheme of operation of a vibrating machine for cleaning and washing machine parts in a pulsating flow of liquid with solid particles is considered and parameters that affect its performance are determined. The results of studies of physical phenomena during the formation of a pulsating submerged jet are presented, and the influence of design parameters and modes of the drive robots on the maximum jet pressure is determined. An analytical dependence of the maximum instantaneous pressure of the jet has been obtained experimentally, which makes it possible to determine the optimal ratios of parameters when designing a vibration machine for cleaning and washing contaminants.

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The reduction of the reaction torque of a straight four-cylinder four-stroke engine

Combustion Engines ◽

10.19206/ce-117139 ◽

2010 ◽

Vol 142 (3) ◽

pp. 82-87

Author(s):

Ryszard MOSAKOWSKI

Keyword(s):

The State ◽

Propulsion System ◽

Design Parameters ◽

Complete Elimination ◽

Engine Operation ◽

Vehicle Propulsion ◽

The Impact ◽

Reaction Torque ◽

Stroke Engine ◽

Selection Of

The paper presents both the exact and simplified relations on the course of the reaction torque of a single and multi-cylinder engine, which is transmitted to the vehicle frame or foundation. The formula for the distance between the balance shafts along the vertical axes ensuring a complete elimination of the impact of the forces of inertia on the course of the reaction torque in four-stroke four-cylinder engines is derived in the paper. The criteria for selecting the optimum value of the distance are also derived in the paper. The dependence of the optimum value of the distance on the state of the engine operation and design parameters of the vehicle propulsion system is indicated in the paper. The paper proposes the selection of the optimum shafts distance, for a given type of vehicle, in areas of the engine most frequently used operating states.

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Methodology for substantiating the design parameters of a single-tube hydropneumatic shock absorber

Вестник гражданских инженеров ◽

10.23968/1999-5571-2020-17-4-166-173 ◽

2020 ◽

Vol 17 (4) ◽

pp. 166-173

Author(s):

A. M. Voytko ◽

Keyword(s):

Comparative Analysis ◽

Energy Intensity ◽

Shock Absorber ◽

Design Parameters ◽

Working Fluid ◽

Hydraulic Shock ◽

Single Tube ◽

Operating Modes ◽

Shock Absorbers ◽

Selection Of

The article describes the developed methodology for calculating the parameters of a single-tube hydropneumatic shock absorber. The calculation procedure is presented including calculating the volume of the gas filling cavity, calculating the parameters of the gas and the working fluid, determining the energy intensity of the shock absorber, checking the possibility of cavitation in the operating modes, as well as calculating the strength of the shock absorber parts.. A comparative analysis results of the calculated characteristics and the experimental characteristics of the hydropneumatic shock absorber are presented, the absorber having been produced according to the obtained design parameters. Based on the analysis, recommendations are given to increase the running smoothness of the car by replacing the standard hydraulic shock absorbers with hydropneumatic ones, taking into account the selection of the throughput of the discharge valves.

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Definition of rational operating modes of a vibratory jaw crusher

Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu ◽

10.33271/nvngu/2021-4/056 ◽

2021 ◽

pp. 56-62

Author(s):

Ye.O Mishchuk ◽

I.I Nazarenko ◽

D.O Mishchuk

Keyword(s):

Mathematical Model ◽

Impact Action ◽

Efficient Operation ◽

Motion Equations ◽

Operating Modes ◽

The Third ◽

Jaw Crusher ◽

Elastic Systems ◽

Definition Of ◽

The Impact

Due to the continuous development of the building-and-construction industry, it is necessary to design new or modify outmoded industrial equipment. Using jaw crushers with the impact action of crushing plates on material is a perspective line of developing crushing equipment. Purpose. Developing a mathematical model of a vibratory jaw crusher and studying the operational process which is based on the mathematical model in order to design new crushers. Methodology. Definition of the crusher working process is based on the main statements of the theory of mechanical oscillations and the theory of continuous environment. In the motion equations of the crusher the material is taken into account on the basis of a discrete model by a continual parameter. Findings. A physical model is developed on the basis of which motion equations are derived, which include three main conditions of the efficient operation: 1) the elasticity of the second vibrating element must exceed or be equal to crushing force; 2) vibrations of the first and the third vibrating elements must be in phase, and vibrations of the second vibrating element must be in antiphase; 3) the summarized displacement of the second and the third crushing plates must ensure crushing of material. Graphs of the effect of the vibrating elements and elasticity coefficients of elastic systems on the amplitudes of vibrations are plotted and analyzed. On the basis of the motion equations, with consideration for the optimal parameters of the crusher vibrating elements and for the elasticity coefficients of the elastic systems, the amplitude-frequency characteristics of the crusher for different frequency ranges are determined. Set up is an equation describing the displacement of material in the crushing chamber for a time interval required for the crushing plates to be separated. Presented are graphs of dependency of the amplitude of vertical vibrations of the crusher casing on the elasticity of the isolating elastic system, and provided are recommendations for selecting and calculating vibration isolation. Originality. A mathematical model of an experimental vibratory jaw crusher and the characteristics of the experimental crusher are presented, on the basis of which recommendations are given for the selection of energy-efficient operating modes of the crusher. Practical value. Knowledge on the rational values of the frequency ranges for operation of the studied vibratory jaw crusher makes it possible to determine the optimal level of power consumed by the crusher and efficiency in processing materials of different hardness.

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Methods for Restricting Maximum Exposure Rate in Computerized Adaptative Testing

Methodology ◽

10.1027/1614-2241.3.1.14 ◽

2007 ◽

Vol 3 (1) ◽

pp. 14-23 ◽

Cited By ~ 9

Author(s):

Juan Ramon Barrada ◽

Julio Olea ◽

Vicente Ponsoda

Keyword(s):

Measurement Accuracy ◽

Computerized Adaptive Testing ◽

Computation Time ◽

Adaptive Testing ◽

Exposure Rate ◽

Control Parameters ◽

The Impact ◽

Two Alternatives ◽

Selection Of ◽

Maximum Exposure

Abstract. The Sympson-Hetter (1985) method provides a means of controlling maximum exposure rate of items in Computerized Adaptive Testing. Through a series of simulations, control parameters are set that mark the probability of administration of an item on being selected. This method presents two main problems: it requires a long computation time for calculating the parameters and the maximum exposure rate is slightly above the fixed limit. Van der Linden (2003) presented two alternatives which appear to solve both of the problems. The impact of these methods in the measurement accuracy has not been tested yet. We show how these methods over-restrict the exposure of some highly discriminating items and, thus, the accuracy is decreased. It also shown that, when the desired maximum exposure rate is near the minimum possible value, these methods offer an empirical maximum exposure rate clearly above the goal. A new method, based on the initial estimation of the probability of administration and the probability of selection of the items with the restricted method ( Revuelta & Ponsoda, 1998 ), is presented in this paper. It can be used with the Sympson-Hetter method and with the two van der Linden's methods. This option, when used with Sympson-Hetter, speeds the convergence of the control parameters without decreasing the accuracy.

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