Suspended Monorail Research Articles

Explosive atmosphere ignition source identification during mining plant suspended monorail braking unit operation

Coal dust and methane explosions are some of the most common causes of mining disasters in hard coal mines all over the world, and research continues to be conducted with the purpose of understanding the mechanisms of an explosion, explosion prevention and risk reduction. This article presents the test methodology as well as virtual and bench test results for a braking unit, which constitutes one of the main components of a suspended monorail transport system. The design work and virtual and bench testing were performed as part of a European research programme. The tests were conducted in a dedicated specialist test facility. The tests were based on Polish standard PN-G-46860:2011, concerning braking trolleys employed in mining plant suspended railway systems. The tests also factored in the requirements for non-electrical devices intended for use in explosive atmospheres, including braking systems, as defined in standard PN-EN ISO 80079-36:2016, harmonised with the ATEX directive. The test scope encompassed braking unit operational component temperature measurements using thermal imaging and the contact method, as well as braking distance measurements. Further tests involved virtual simulations of brake pad heating. The tests employed the finite element method (time-varying calculations). Results obtained over the course of numerical calculations indicate that brief brake pad friction face heating, even up to a temperature exceeding 200C, does not result in inward heat propagation towards the brake pad material. This is also confirmed by the measurement results. However, under real conditions, the braking unit would be engaged only during an emergency situation, which would not lead to exceeding the permissible brake shoe material temperature values.

Substantiation of performance indicators of mine monorail locomotives

Mine transport is an integral part of mining process. The performed analysis of modern monorail autonomous locomotives indicates that this type of underground auxiliary transport is the most promising today due to a number of advantages that were identified in this study. To assess performance indicators of mine monorail locomotives, a number of characteristics are currently used, for instance, the dependences between several parameters of propulsion system operation. The type of characteristic is determined by an independent variable to be selected from the list of the operational or design parameters. To substantiate performance indicators of autonomous mine suspended monorail locomotives, the authors proposed the relationship between the characteristics of the traction energy chain equipment and the diesel locomotive propulsion system efficiency factor. To assess the efficiency of mine suspended monorail locomotive operation, a composite indicator for assessing efficiency of various types of traction was proposed: the operational efficiency factor. This indicator takes into account varying the efficiency factor of the energy chain units depending on their operating modes. When determining the functional dependencies of varying the efficiency factor of power and auxiliary units of monorail locomotives, a grouping of the main parameters according to the features depending on the economic characteristics of the propulsion system and its operating modes was proposed. The operational efficiency factor of the locomotive as a whole is determined both by the economic characteristics of all units of its energy chain and by the modes of their operation.

Experimental and numerical investigations on longitudinal vibration of suspended monorail trains induced by bogie pitching motion

The longitudinal harmonic vibrations found in the suspended monorail train (SMT) seriously affected the ride quality and dynamic behaviour. In this work, the experimental and simulated analyses are carried out to reveal the essential phenomenon, occurring mechanism and possible solutions to this issue. Firstly, the ride quality and vibration transmission of the tested SMT system are investigated. It is found that the longitudinal vibrations with the frequency of 2.7Hz occur to the carbody, bogie frame and suspension of the train system. Due to the secondary suspension is lower than the gravity center of the bogie frame, the bogie pitch motion with low damping ratio can be easily excited. The longitudinal components of the bogie pitch motion will transfer to the carbody and wheelset through traction rod and primary suspension, respectively. After that, the multibody dynamic model of a suspended monorail train is developed. Based on the numerical model, some parametric simulations, e.g. rubber stiffness, traction rod height and secondary damping, etc., are carried out to propose solutions to relieve the longitudinal vibrations. Finally, the field tests for the SMT arranging the longitudinal dampers are conducted to verify its improvement to longitudinal vibrations.

Coupled vibration analysis of suspended monorail train and curved bridge considering nonlinear wheel-track contact relation

This work elaborately conducts the coupled vibration analysis of suspended monorail train and curved bridge (SMTCB) considering a nonlinear wheel-track contact relation. First, a high-efficiency coupled dynamic model of the SMTCB is developed based on a co-simulation method where the train subsystem is established using the multi-body dynamics software UM and the curved bridge subsystem is built adopting the finite element software ANSYS, whose modal information is extracted to put into the UM software; Two subsystems of the train and bridge are coupled by an improved wheel-track contact model (IWTCM) that considers the real nonlinear radial stiffness of a suspended monorail rubber tire. Then, the effects of the extracted modal orders of the bridge on vehicle-bridge vibrational responses are analyzed and discussed in detail, and the minimum modal orders extracted of the bridge that guarantee the convergence and accuracy of the proposed model are also obtained. Subsequently, the vibrational responses obtained by numerical simulation and field test are compared when the vehicle runs on a curved bridge, validating the reliability of the developed model. On this basis, by comparing the vehicle-bridge vibration responses between the traditional FIALA tire model and the IWTCM, some remarkable differences are distinguished, revealing the significances and advantages of adopting the IWTCM. Finally, employing the developed model, the vehicle-curved bridge coupled vibration features are investigated comprehensively and several key parameters are also chosen reasonably. The research results may provide some useful guidance for the design of the SMTCB.

Impact of Increased Travel Speed of a Transportation Set on the Dynamic Parameters of a Mine Suspended Monorail

The method of increasing the efficiency of using one of the most common means of auxiliary transport in underground coal mines—suspended monorails—is presented. Increase of velocity is one of the key parameters to improve the efficiency and economical effect related with the underground auxiliary transport. On the other hand, increasing the velocity results in bigger value of force acting on the suspended monorail route and its suspensions. The most important issue during increasing the velocity is ensuring the required safety for the passengers and not overloading the infrastructure. In order to analyze how increasing velocity influences the level of loads of the route suspension and the steel arch loads, the computational model of suspended monorail was developed. The computational model included both the physical part (embedded in the program environment based on the Multi-Body System method) and the components of the monorail control system. Two independent software environments were cooperating with each other through the so-called co-simulation. This model was validated on the base of results obtained on the test stand. Then, the numerical simulations of emergency braking with different values of velocity were conducted, which was not possible with the use of physical objects. The presented study can be used by the suspended monorail’s producers during the designing process, and leads to increase the safety on underground transportation routes.

Research of the Rate of Changing the Mine Suspended Monorail Brakeforce When Braking

A technique to determine the rate of increase in brakeforce developed by the braking device of a mine suspended monorail is proposed. Based on the experimental study, the results of the analysis of the rate of change in the brakeforces developed by the brake shoes are given.

Dynamic interaction analysis of suspended monorail vehicle and bridge subject to crosswinds

This paper develops a fully coupled wind-vehicle-bridge (WVB) interaction model to evaluate the dynamic performance and riding comfort of the suspended monorail vehicle-bridge system subject to turbulent crosswinds. The dynamic interactions between the vehicle and the bridge, the wind and the bridge, and the wind and the vehicle are considered in the model. The suspended monorail vehicle is modeled as a mass-spring-damper system and the motion equations of the multi-body system are derived. Through generating nonuniformity wind velocity fields consisting of various wind average velocities, an accurate approach to simulate the actual aerodynamic wind forces acting on the bridge and on moving vehicles is proposed. Further, a multi-span bridge is chosen as an example to illustrate the dynamic behaviors of the proposed WVB system. Results indicate that the turbulent crosswinds could have a great influence on the dynamic performance of the suspended monorail vehicle-bridge system, and it should be taken into account in the simulation of aerodynamic wind forces to guarantee the accurateness of vehicle vibration analysis. Besides, passengers could experience uncomfortable when vehicles pass through the bridge under strong turbulent crosswinds.

Dynamic effects of turbulent crosswinds on a suspended monorail vehicle–curved bridge coupled system

The present article proposes a novel framework for analyzing the dynamic responses of suspended monorail vehicles running over curved bridges under crosswinds. In this model, the curved bridge model is established with the finite element method and vehicles are simulated as a multibody system. Subsequently, a wind model is proposed with the wind tunnel test, spectral representation method, and yaw wind-decomposition method, taking into account the effects of the angle between the wind and vehicle changes when vehicles pass through the curved bridge. Finally, a suspended monorail curved bridge is analyzed to demonstrate the effect of the wind model on the vibration of the system. The results show that wind direction has a great effect on the lateral dynamic response of curved bridges, the lateral force of guiding tire, and the vertical force of running tire. The influence of crosswind on the dynamic response of the vehicle decreases with the increase of running time of vehicle on curved bridges.

Impact coefficient analysis of track beams due to moving suspended monorail vehicles

To study the impact coefficient of track beams due to moving suspended monorail vehicles under the bridge deck, this paper presents a vehicle-bridge dynamic model based on the rigid-flexible coupling method. Finite element method is used to establish the bridge model, and the vehicle is simulated as a multi-body dynamic model The mechanical characteristics of running tire are precisely modelled and the dynamic equations for the suspended monorail vehicle-bridge coupling system are derived. The proposed approach employs a double-line 7-span bridge with 210 m length as a numerical example, the impact performance of two track beams are studied and the results are verified by comparing with the theoretical solutions. The influences of critical system parameters, such as the train formation and double-line trains loads, on the dynamic responses of vehicles and the bridge are explored. The results show that it is feasible to study the impact effect with the proposed method. The separation phenomenon of rubber running tires jumping up on track surface occurs when vehicle speed is high, which may lead to negative impact coefficients. The impact coefficients of the track beam vary much with different locations, which can even be negative values at locations nearing the pier area.

Intelligent batch process method for analyzing the effect of the suspension parameters on the vibration of the suspended monorail

As for the batch process, it is needed to carry out a unique simulation for each group of parameters. The simplest method to achieve this goal is to uses the Simulink as the integration space. It cannot solve some complicated dynamic model set up in dynamic software. This paper introduces an intelligent batch program to enable the model solved in the dynamic software during the simulation. This paper also put forward the road equation for the suspended monorail, which has not been introduced before. The results of multi rigid body dynamics and vehicle bridge coupling dynamics are compared in this paper. It proves that the bridge vibration has little effect on the vehicle system. Through the batch process method, the effect of different parameters on the vehicle system could be obtained.

ДИНАМИКА ТЯГОВОГО УСТРОЙСТВА ШАХТНОЙ ПОДВЕСНОЙ МОНОРЕЛЬСОВОЙ ДОРОГИ

During the operation of the mine suspension monorail track and traction device form a mechanical system experiencing high dynamic loads associated with implementation of traction and braking forces. Emerging dynamic loads lead to formation of elastic deformations and oscillations that cause vibrations, which leads to displacement of drive wheels and reduces the implementation of traction. The study of the dynamics of traction device is an important step in improving safety and reliability of monorail transport. The aim of the work is to study dynamics of a friction-type traction device moving along a suspended monorail to assess influence of parameters of the elements of device on the vibrations and nature of interaction of drive wheels with monorail. Research methods. Mathematical modeling of the oscillatory processes resulting from interaction of the running gear of the traction device with the monorail is used. Stages of research include drawing up a design diagram oscillations of drive wheels of the traction device interacting with the monorail, developing a mathematical model for the analysis of vibrations caused by moving loads, also assessing the influence of structural parameters of mechanical system under consideration on nature of oscillations. Research results. The developed mathematical model of friction-type traction device movement allows us to establish relationship between parameters of structural elements of its running gear and pressure mechanism, as well as nature of vibrations that arise. As a result, frequencies of the mechanical system under consideration and maximum deviations were found, which allows you to set optimal device parameters to increase traction and increase lifespan of monorail suspended roads. Findings. It was determined that the frequency range of vibration of drive wheels mainly corresponds to the mid-frequency local vibrations of 16–36 Hz. Increasing length of lever for fixing axles of wheels and reducing their radius leads to formation of low-frequency vibrations with a frequency of less than 15 Hz. When length of lever of drive wheels is more than 0.5 m, shoulder of the spring is more than 0.6 m and radius of drive wheels is less than 0.25 m, vibrations with frequencies below 5 Hz can occur. It was found that increasing the length of lever for securing spring increases the oscillation frequency of one drive wheel and reduces frequency of the other. The difference between these frequencies significantly affects changes in the pressure of the wheels against monorail. When difference between frequencies is more than 10–12 Hz, direction of load changes pulsed, with a maximum swing of 0.02 rad, which reduces formation of fatigue fractures of tire wheels, and moments of decrease and increase in pressing force have a negative effect on traction, leading to slippage of drive wheels. When difference between frequencies is less than 10–12 Hz, direction of the load changes sharply, with a maximum swing of 0.03 rad, which increases deformation and formation of fatigue fractures of tire wheels, and short moments of weakening and increase of pressing force, constituting 0.1–0.3 s does not have a significant negative effect on traction.

Wirtualne prototypowanie kolejki podwieszonej w aspekcie zwiększenia jej dopuszczalnej prędkości jazdy w kopalniach węgla kamiennego

Due to the longer distance of moving the crew to the workplace in hard coal mines, the possibility of increasing the maximum permissible speed of suspended monorails was considered. To ensure an adequate level of safety, decelerations affecting the crew in the case of emergency braking in various travelling conditions were analysed. The computational model was verified based on the results of the bench tests on a dedicated test track. The article presents a comparison of results of numerical calculations with measurements at the test stand, and results of numerical simulations in relation to the criterial states that could not be checked at the test stand as well as the analysis of overloads that affect the crew during the emergency braking. These overloads have a significant impact on safety of the operator and passengers, and their determination and analysis may be the basis for assessing the degree of safety as well as for the development of guidelines for designing the additional equipment for the operator's cabs and passenger cars, i.e. components increasing their safety

Methods for Computer Aiding the Configuration and Assessment of Auxiliary Mine Transportation Means

Abstract Mine transportation of materials in underground mine workings is realized by mine underground railways as well as by suspended monorails or floor-mounted railway. Transportation is realized on tracks placed on the floor of working or on rails suspended to roadway support. Each transport operation must be preceded by a transport design project, made in accordance with obligatory legislation. A part of the project are traction calculations. Their implementation in a computer program allows for minimization of the possibility of errors during the configuration of suspended queues and conducting traction calculations, which consequently leads to improve the level of safety. The article discusses the modular Safe Trans Design system, supporting the design of auxiliary mine transportation. The system has been implemented in the mines of JSW S.A. The assumptions and structure of the system as well as algorithms of operation of the ‘configurator of transportation sets’ and ‘assessment and reporting module’ are presented. The method of creating an auxiliary mine transportation system project is presented. Safe Trans Design system is used in planning, organizational and training activities implemented as part of transport safety management in mining plants. Developed methods can be easily adapted to other legislations of hard coal producers’ countries, where suspended monorails are used in underground auxiliary mining transportation systems.

Study of the braking regime of rolling stock mining suspended monorail taking into account clearances in the coupling

Introduction. Currently, mine suspended monorails are becoming more common in coal mines for auxiliary cargo and people transportation. Compared to ground transport, monorail has significant differences, which does not allow to fully use the previously obtained results of braking modes studies. Research aims to establish regularities in the processes that occur during the mine suspended monorail road rolling stock braking mode, taking into account clearances in the couplings. Methodology. To substantiate the parameters and designs of brake and coupling devices of a mine suspended monorail, a mathematical model of rolling stock movement along the monorail has been developed. Results. Dependencies are established that describe the process of rolling stock braking on a monorail. Motion parameters for different values of stiffness, damping and clearances in the couplers are analyzed. It is established that the gaps in rolling stock coupling influence the value of undercarriage and suspension units longitudinal vibrations amplitudes. Conclusions. A mathematical model of rolling stock movement is developed with allowance for clearances in the coupling making it possible to simulate mine suspended monorail braking mode.

The Influence of an Operating Conditions on the Friction Coefficient in Transportation Machines Drives

Abstract The publication presents the construction of the station for testing the friction coefficient under high pressure and low slip velocity values. These conditions of cooperation of friction pairs occur in the drives of transport machines such as belt conveyors and suspended monorails. The value of the friction coefficient, depending on the operating conditions such as moisture and rock or coal dust pollution, has a significant impact on the correct and efficient operation of such drives. The features of the station allow mapping the operating conditions on a laboratory scale. As part of the research, appropriate friction samples made of rubber or polyurethane were prepared. Referring to the conditions of conveyor operation and conditions of contact of the conveyor belt with the drive drum, the values of unit pressures and values of slip speed occurring in the drum drive of the belt conveyor were determined. A series of laboratory tests were carried out for the friction pair rubber drum lining – conveyor belt cover. The tests were carried out for four different states of friction vapor surfaces, namely for dry and wet samples, as well as for samples in clean or contaminated with stone dust. As a result of the tests, the values of friction coefficients for various surface states were determined, which will be valuable information for designers of friction drive systems of transport devices.

Vibrations diagnostics and analysis in operator’s and passenger cabins of a suspended monorail

Vibrations diagnostics and analysis in operator’s and passenger cabins of a suspended monorail

Improvement on Curve Negotiation Performance of Suspended Monorail Vehicle Considering Flexible Guideway

This work presents the investigation and improvement on curve negotiation performance of suspended monorail vehicle considering a flexible guideway. First, a spatial train–guideway interaction model of suspended monorail system (SMS) is established based on the secondary development of ANSYS software. Then, the dynamic analysis of the train over the flexible curved guideway is conducted, and the curve negotiation performance of the vehicle and the guideway vibration feature are revealed. Subsequently, several crucial design parameters that significantly influence the curve negotiation performance of the vehicle are found, and their influences on the train–guideway dynamic responses are systematically investigated. Finally, by comprehensively considering the dynamic indexes of the vehicle–guideway system, the optimal ranges of these crucial design parameters are obtained. Results show that decreasing the radial stiffness of guiding tyre can effectively reduce the lateral vibration levels of vehicle and guideway, but it would increase the lateral displacements of the bogie and hanging beam; and the radial stiffness is finally suggested to be around 1[Formula: see text]kN/mm by comprehensively considering all dynamic indexes. Increasing the initial compression displacement of guiding tyre can well limit the lateral displacements of the bogie and the hanging beam, thus enhancing the train running safety; however, it would intensify the vehicle-guideway lateral vibration level; especially, the optimal initial compression displacement of guiding tyre is related to its radial stiffness characteristics. To ensure a good curve negotiation performance of vehicle and guideway vibration level, the stiffness of the anti-roll torsion bar and the initial gradient angle of the installed trapezoid four-link suspended device are suggested to be 1.0[Formula: see text]MNm/rad and 65–[Formula: see text], respectively.

An improved dynamic model of suspended monorail train-bridge system considering a tyre model with patch contact

This study aims to elaborately investigate the dynamic performance of suspended monorail train-bridge system (SMTBS) by establishing an improved train-bridge interaction model considering a tyre model with patch contact. First, to reasonably model the contact behaviour between tyre and bridge, a tyre model with patch contact is established by using the continuous radial spring-damping elements. Subsequently, the stiffness and damping performances of a driving tyre used in the SMTBS are studied based on a full-scale laboratory experiment, and then the parameter identification of the established patch contact tyre model is accordingly conducted with the test data. On this base, an improved integrated train-bridge interaction model considering the tyre model with patch contact is developed by using ANSYS parameter design language (APDL), and its reliability is also validated by the field test. Further, by a comparison of train-bridge dynamic responses between the point-contact tyre model and the patch contact tyre model under different conditions, some obvious discrepancies are pointed out, and the advantage and significance of the patch contact model are also revealed. Finally, by applying the proposed model, the train-bridge dynamic performance is studied systematically when a train travels on the curve bridge, revealing the curve negotiation characteristics of vehicle as well as the bridge vibration performance. Meanwhile, several key design parameters of vehicle subsystem are selected optimally by comprehensively considering all vehicle-bridge dynamic indices. The research results may be beneficial to the dynamic performance improvement and optimal design of the SMTBS.

A dynamic analysis scheme for the suspended monorail vehicle–curved bridge coupling system

Based on the rigid–flexible coupling method, an original scheme for the dynamic analysis of the vehicle–bridge interaction between suspended monorail trains and horizontally curved bridges is proposed. Considering the compression deformation and contact model of walking tire and guiding tire, the geometric and mechanical coupling relationships between vehicle and bridge are studied, and the dynamic equations of suspended monorail vehicle–bridge interaction are derived. A vehicle–curved bridge coupling vibration system is established according to transformable relationship between the local coordinate system and the global coordinate system in SIMPACK. Considering a curved bridge under passage of suspended monorail vehicles as an example, the influences of critical system parameters, such as the superelevation, vehicle speed, and bridge curve radius, on the dynamic responses of vehicles and the curved bridge are explored. It is shown that the direction of the yawing moment of the front bogie is in accordance with the turning direction of the vehicle, while the yawing moment of the rear bogie is in the opposite direction. The superelevation has great influence on the lateral guiding force and vertical walking force of vehicle, and vehicle speed is a key factor to the running safety of suspended monorail vehicle. In addition, the curve negotiation ability of vehicle is better with the increase in bridge curve radius.

Field measurement of the dynamic responses of a suspended monorail train–bridge system

This work presents an integrated and large-scale field measurement of the dynamic responses of a suspended monorail train–bridge system, which is rarely reported. This experimental train uses a high-capacity lithium battery for the operation. The maximum running speed of the train is up to 60 km/h. The experimental line was constructed on a full-scale steel bridge composed of a straight section, curved sections with different horizontal radiuses and a slope section of 60‰. First, the train–bridge dynamic responses under different conditions are extracted based on the field test. Then, the car-body accelerations under different train speeds and bridge sections are analysed in detail, and the running stability of the vehicle is assessed by adopting the Sperling index. By comparing the dynamic responses of the train–straight bridge interaction and the train–curved bridge interaction, some significant discrepancies and interesting phenomena could be found. Subsequently, based on the test data, the vertical rotation angles of the beam end and the dynamic amplification factors of the bridge displacements under different vehicle speeds and bridge sections are obtained, and then the vibration levels of the bridge under different conditions are evaluated. Finally, by analysing the frequency spectra of the dynamic responses, the dominant frequencies of the acceleration signals of this monorail vehicle and bridge subsystems are revealed; in addition, the sensitive wavelengths that influence the running stability of the vehicle are found. These measurement results may provide valuable guidance for the design of the suspended monorail system and numerical model validation.