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Constant exploitation of heavy duty machines, such as the bucket wheel excavator and bridgetype stacker-reclaimer, under the action of highly pronounced dynamic loads, may lead to the failures of their substructures and subassemblies. Unfortunately, high position among the causes of mentioned failures belongs to the designers omissions - mistakes done on the occasion of load analysis, modelling and response analysis. This paper presents an original procedure of calculating external loads caused by force resisting excavation. Model comprises all relevant structural parameters and parameters of duty cycles. Measurements in the real operating conditions have been done in order to establish the credibility of simulation model. Besides that, this paper discusses procedures for dynamic modelling of bucket wheel excavator superstructure. Developed model enables response analysis, with quite satisfactory accuracy, from the engineering point of view. Redesign of the bucket wheel excavator slewing platform, as well as redesign of the bridge-type stacker-reclaimer structure, is presented. The efficiency of these reconstructions is unquestionably confirmed by failureless service of mentioned machines.

Puharic M.,Institut Gosa | Lucanin V.,Masinski Fakultet | Ristic S.,Institut Gosa | Unic S.,Institut Gosa
Journal of Applied Engineering Science | Year: 2010

This paper presents the aerodynamical brake system, as second brake system, in cases when it is necessary to speed down the train or at emergency situations when primary brake system Is out of order. In this brake system, braking force is a result of aerodynamical drag generated on pulled-up aerodinamical brake panels. These panels are especially effective at high speeds because aerodynamical drag of panels is proportional to second exponent of vehicle's speed. Calculation of braking force by panel surface unit was derived for the aerodynamical brake of concave shape and it was compared with test results for Maglev train on railway Yamanashy in Japan.

Ognjanovic Z.,Matematicki Institute SANU | Doder D.,Masinski Fakultet | Markovic Z.,Matematicki Institute SANU
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

We introduce a propositional logic whose formulas are built using the language of CTL*, enriched by two types of probability operators: one speaking about probabilities on branches, and one speaking about probabilities of sets of branches with the same initial state. An infinitary axiomatization for the logic, which is shown to be sound and strongly complete with respect to the corresponding class of models, is proposed. © 2011 Springer-Verlag.

Milanovic M.,Insitut Mihajlo Pupin | Celebic V.,Insitut Mihajlo Pupin | Salom I.,Insitut Mihajlo Pupin | Prezelj J.,Masinski Fakultet | Todorovic D.,Dirigent Acoustics
2014 22nd Telecommunications Forum, TELFOR 2014 - Proceedings of Papers | Year: 2014

This paper describes the realization of an FPGA platform designed for real time acoustic signal acquisition and data procebing. The paper presents complete developement proceb, starting from high level system design including signal integrity simulations to real system measurement results based on described platform. A real system for localization of the dominant noise source based on the platform is presented. © 2014 IEEE.

Hasecic A.,Masinski Fakultet | Muzaferija S.,CD adapco | Demirdzic I.,CD adapco
Numerical Heat Transfer; Part A: Applications | Year: 2016

ABSTRACT: A mathematical model which can describe flows of a number of immiscible fluids at high temperatures, where the radiative heat transfer cannot be neglected, is presented. It combines an interface-capturing multiphase model and the P-1 radiation model chosen for its simplicity. A finite volume method is utilized to discretize the governing equations and the solution methodology is based on the SIMPLE algorithm. The model implementation is verified on a number of simple problems. The numerical experiments show a good agreement with analytical solutions or results which could be found in literature. A cooling of a gas–liquid system inside a rotating tank is also simulated. The results show that a coupled modeling of the motion of a number of fluids and all fundamental modes of heat transfer are important. Neglecting the convective transport and resulting redistribution of phases, or neglecting the radiative heat transfer, could result in significant modeling errors. © 2016, Copyright © Taylor & Francis Group, LLC.

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