The Impact of the Eccentricity of the Tension Pulley on the Dynamic Response of the Stacker Superstructure

Stackers are one of the vital parts of the system that work on the exploitation of coal in open-pit mines. During their exploitation life, they are exposed to hard working conditions in which dynamic and stochastic loads act on them. Therefore, the analysis of their dynamic behavior is necessary in order to prevent failures and ensure a longer working life. Given that the structure of the stackers is a dominantly spatial truss structure, the paper presents the procedure of forming a spatial reduced dynamic model of the stacker superstructure and analysis of the influence of the eccentricity of the discharge boom tension pulley created during the production process. The results are given through the displacements and accelerations of the referent points of the structure. The quantification of the eccentricity influence from the aspect of the dynamic behaviour of the machine is presented and discussed

The Impact of the Eccentricity of the Tension Pulley on the Dynamic Response of the Stacker Superstructure

Stackers are one of the vital parts of the system that work on the exploitation of coal in open-pit mines. During their exploitation life, they are exposed to hard working conditions in which dynamic and stochastic loads act on them. Therefore, the analysis of their dynamic behavior is necessary in order to prevent failures and ensure a longer working life. Given that the structure of the stackers is a dominantly spatial truss structure, the paper presents the procedure of forming a spatial reduced dynamic model of the stacker superstructure and analysis of the influence of the eccentricity of the discharge boom tension pulley created during the production process. The results are given through the displacements and accelerations of the referent points of the structure. The quantification of the eccentricity influence from the aspect of the dynamic behaviour of the machine is presented and discussed

Bus Fleet Management – A Systematic Literature Review

The research on Bus Fleet Management (BFM) has undergone significant changes. It is unclear whether these changes are accepted as technological change or as a paradigm shift. Perhaps unintentionally, BFM is still perceived as routing and scheduling by some, and by others as maintenance and replacement strategy. Therefore, the authors conducted a Systematic Literature Review (SLR) to overview the existing concepts and school of thoughts about how stakeholders perceive the BFM. The SLR post-study exposed that BFM should be acknowledged as a multi-realm system rather than a uniform dimension of fulfilling timely service. Nonetheless, the work encapsulates BFM evolution which shows the need for the multi-realm research abstracted as "Bus Fleet Mobility Management" and "Bus Fleet Asset Management". The difficulties of transport agencies and their ability to switch from conventional to Zero-Emission Buses (ZEBs) illustrates why we propose such an agenda, by which the research is validated through needs both in academia and in practice

Analysis of the potential of the Port of Novi Sad to become a new container terminal on Danube

This paper discusses the possibility the establish and construct a new container terminal in the Port of Novi Sad which has regional and international importance and good geographical position, located in the Serbian Autonomous Province of Vojvodina. The provided analysis presents current container flows in Serbia and the forecast for the next 5 and 10 years (including three scenarios: realistic, pessimistic and optimistic), at first for the whole country, but later on the analysis was focused on the Danube gravitating regions in Serbia and finally to the existing Port of Novi Sad in order to evaluate its potential to become a logistics center. It was concluded that the construction of a new container terminal in the Port of Novi Sad on the Danube aims to bring about a significant change in the container transport system in Serbia, but also in the region or the Danube countries

Analysis of the potential of Serbia to transport containers on Danube

This paper deals with problems and possible solutions for the improvement of container transport of Serbia by using Danube as a waterway. Given the geographical position in relation to the Danube, Serbia has a sufficient number of ports on this river, which could be an element of further development of the economy and therefore can be considered as a great potential. An analysis of import and export of container that was done in this paper indicates that Serbia has substantial potential to transport containers on Danube. Consequently, there are sufficient justifications for the design and construction of a modern container terminal on the Danube which will connected Serbia with main Europian ports and which will contribute to the further progress of the Serbian economy

Implementation of a Non-Linear Regression Model in Rolling Bearing Diagnostics

The reliable operation of a mechanical system is dependent on the condition of installed rolling bearings. This paper presents a measuring system and equipment for analyzing the condition of rolling bearings. The developed system is a modular device (VibroLog) for measuring several diagnostic parameters for bearings, including vibration, number of revolutions, temperature and sound pressure. The device is a data collector and analyzer. Software in the Java programming language for the analysis and presentation of data obtained by VibroLog has also been developed. This paper is concerned with the development of a mathematical model for the evaluation and prediction of the qualitative state of rolling bearings in real operating conditions. It also presents results of measurement and mathematical modelling of the results. The model was formed by non-linear regression analysis as one of the most widely used statistical techniques. The analysis of the experimental data showed that the rate of change of a variable is proportional to its actual value. The model was tested on several rolling bearings having different degrees of damage. The developed model makes it possible to evaluate and predict the condition of the bearing by measuring the sound pressure level, which is simpler than vibration measurement in real operating conditions. During testing, the model generated results within the prediction error limits. The developed vibrodiagnostic system and the created model enable condition assessment and prediction for a wide range of rolling bearings

Analysis of the potential of the Port of Novi Sad to become a new container terminal on Danube

This paper discusses the possibility the establish and construct a new container terminal in the Port of Novi Sad which has regional and international importance and good geographical position, located in the Serbian Autonomous Province of Vojvodina. The provided analysis presents current container flows in Serbia and the forecast for the next 5 and 10 years (including three scenarios: realistic, pessimistic and optimistic), at first for the whole country, but later on the analysis was focused on the Danube gravitating regions in Serbia and finally to the existing Port of Novi Sad in order to evaluate its potential to become a logistics center. It was concluded that the construction of a new container terminal in the Port of Novi Sad on the Danube aims to bring about a significant change in the container transport system in Serbia, but also in the region or the Danube countries

Finite Element and Analytical Modelling of Ship Unloader

The paper deals with the mathematical modelling of the dynamic behavior of the structure of the ship unloader. It is given the procedure for formulation of the reduced dynamic model which retains the main aspects of the behavior of the structure and yet is simple enough to be performed with standard engineering tools. The approach is applied on the real bridge-type grab ship unloader but can also be used on similar complex structures. Initially, the complete structure is modelled with finite element software where the natural frequencies were obtained. This 3D model is reduced to an equivalent plane model of the sea-side part of the boom. The postulation of the analytical approach is based on the model of a simple beam with an overhang where dynamic analysis is concerned with the Rayleigh Ritz method for estimating the adopted admissible functions. The results of the modal analysis of the reduced mathematical model showed a small difference from the results of finite element analysis which stands for the verification of the presented approach

Analysis of the impact of the frequency-controlled bucket wheel drive on the dynamic response of the excavator superstructure

Bucket wheel excavators (BWEs) are the largest mobile terrestrial machines exposed to the working loads of a periodic character. This paper presents a small portion of the studies, conducted with the goal of proposing a new idea regarding preservation of the load-carrying structures of these machines, based on the implementation of a controllable frequency-controlled drive of the excavating device. A detailed analysis of the dynamic response of the load-carrying structure is required in order to determine the domains of frequency of revolutions of the working device's driving motor where the dynamic response of the structure is favorable, and therefore successfully implement this idea. A methodologically-original study was conducted, using a unique dynamic model of the BWE slewing superstructure that allows for the continuous variation of the frequency of excitation. This has yielded the resonant-free domains, i.e. the domains where the structure is not exposed to the excessive dynamic impacts