A finite element (FE) model of the straight guideway bridge under monorail train has been built in this research in order to investigate dynamic interactions of the coupled system in the vertical and longitudinal direction. A limited length of the straddle monorail bridge including five continuous spans is modeled in three dimensions by using FE method. A 3D model of the monorail train system, built in the multibody analyzer MSC ADAMS, is assembled over the bridge. The entire model, consisting of the vehicle and bridge subsystems, is numerically analyzed by performing dynamic simulation in time domain. The braking forces between the train tires and guideway beams are activated in the analysis, in addition to the dead weights of the components and the train live loads. Dynamic forces in the tires are obtained for the case of the emergency braking in the system. The reaction forces, appeared in the bridge piers, are reported as the input forces for the purpose of the bridge design.
Results of research on the hazard posed by polycyclic aromatic hydrocarbons contained in the dusts emitted from motor vehicle braking systems have been presented. The polycyclic aromatic hydrocarbons (PAHs) constitute a group of chemical compounds that pose a serious danger to the human health, chiefly because of their carcinogenic properties. Investigations into the issue of environmental pollution with polycyclic aromatic hydrocarbons generated by motor vehicle traffic were carried out in connection with the work being done at PIMOT on systems to reduce dust emission from motor vehicle braking systems. The investigations included determination of PAH contents of the dust emitted from vehicle braking systems as well as the PAH concentrations in the indoor air in a room with the stand for testing dust emissions from braking systems and in the duct to carry away gases from that room. Moreover, the PAH contents of soil were measured in the context of location of the soil sampling points in relation to traffic routes. The PAH contents were measured in Warsaw and in Zabrze. The investigation results confirmed that PAHs considered as being most harmful to the human health due to their carcinogenic properties were actually present in the dusts emitted from braking systems. The PAH contents of soil were found to be very sensitive to the location of the soil sampling points in relation to traffic routes and this is a confirmation of the thesis that motor traffic is an important source of environmental pollution with polycyclic aromatic hydrocarbons.
The iron ore mine owned by the state concern of Luossavaara – Kiirunavaara AB-LKAB state concern has several mining skip shaft hoists for drawing iron ore. Despite using modern systems to secure the travel of these hoists in line with the Swedish regulations, units intended for the emergency breaking of vessels must be used in the so-called free travel paths in the tower and in the shaft sump. The paper discusses the main requirements that, in accordance with the Swedish regulations as regards the operational use of mining shaft hoists, must be met by devices of this type and a solution was proposed for a structure design of the braking unit for the mining shaft hoist installed in the B-1 shaft in the Kiruna mine. The frictional braking system in the form of moving bumping beams was decided to be used in the said hoist, developed in the Cable Transport Department in the University of Science and Technology in Krakow. The action of moving bumping beams consists in these beams, placed at the beginning of free travel paths, not only braking the rushing hoist vessels but also (with the integrated units for vessel capture) performing the function of grips. They secure the vessels against falling down into the shaft after the finished braking process. The advantage of such a solution is that the structural elements: the guiding shank of the tower, the head of the vessel and the bumping beams, transfer many times lower values of dynamic forces at the time of the strike of the vessel against the moving bumping beams when compared with dynamic forces arising at the time of the hit of the vessel against the fixed bumping beams. In the process of designing moving bumping beams, braking simulation is an important stage conducted with a computer program developed in KTL AGH. This program enables the modelling of load-bearing and balance ropes as flexible elements with elastic and suppressing properties. The results of these simulations, especially in the scope of the achieved braking deceleration of the vessels, the values of braking distances and forces in the load-bearing ropes are crucial in confirming the correctness of the assumed concept of the emergency braking system. The braking units in the form of moving bumping beams have been executed by the Polish company Coal-Bud Sp. z o.o. and are now being integrated in the tower and in the shaft sump of the B-1 shaft of the Kiruna mine in Sweden.
The aim of the study was to develop an assessment methodology for the temperature of the surface of the friction pair during the braking for mine hoists. During the braking process, the work of friction is transformed into heat at the level of friction surfaces, and in case high temperatures are reached, the friction coefficient is influenced negatively, thus the risk of braking failure exists. In the first part of the study we measured the temperature of the friction surfaces for a particular case of hoist in real braking conditions. In the second part of the study is presented a theoretical model for the calculation of the temperatures resulted in the braking process for the hoist equipped with shoe brakes. The theoretical model for calculation was simulated numerically for a particular case in real braking conditions. Based on the conclusions resulted after the study, a series of hypotheses and recommendations for adjusting the control of the process parameters have been given out, in order to avoid the excessive heating of the brakes of the hoists and, respectively, their improved safety, maintenance and availability.
The antilock brake system (ABS) was developed, which coordinates actions of auxiliary and working braking systems of a trolleybus. A trolleybus type 321 "Belkommunmash", equipped with the proposed ABS was tested in road conditions. The results of tests confirmed compliance of the trolleybus with requirements of the rules UN EEC No 13. Decrease in slippage of the driving wheels, improved stability, roadability and traffic safety of the trolleybus was noted.
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