Vojnotehnicki glasnik / Military Technical Courier

275-286

Authors: Novaković Zoran

The main goal of professional risk rate determination is preventive action in order to secure and protect health of employees. It considers assumption of common and special working protection measures in order to eliminate any danger or damage or to reduce workers exposition time to some risk factors in their working environments. In many cases data on former noxious events are incomplete or statistically insufficiently relevant. So the set of these data is often statistically nonhomogeneous, so are the results of statistical analysis. Thereby rated risks are insufficiently accurate and unreliable. Because of all these things, in this paper is recommend and apply an expert method which annuls this shortage and simultaneously it removes influences that are the consequence of some rate indetermination and subjectivity.

296-307

Authors: Ćuk Danilo

This paper presents the effects of the range extension of an artillery rocket with wrap around fins on its dynamic stability. The increased total impulse of the rocket engine for 50% and flight through the atmosphere layers with low air density extend the range for more than 75% of the nominal range. However, the flight of the unguided rocket through the rarefied air produces difficulties related to the dynamic stability. The small changes in the side moment which is induced by the angle of attack and Magnus moment of the improved rocket can produce instabilities in flight and increasement the angle of attack. The tolerances of the side moment were determined for both basic and improved type of the rocket in order to prevent instable flight. The influence of the range extension on the probable errors in range and cross-range was analyzed as well.

320-328

Authors: Pavlović Milorad, Jurin Gordana

This paper presents the use of noise monitoring system, terminal NMT 3637B and software 7802, Brüel & Kjær in process of jet aircraft noise certification according to standard ICAO Annex 16 and the algoritam for calculating EPNL noise level (Effective Perceived Noise Level) that we created in MatLab environment. This software sublimated all necessary input parameters, acoustic and non acoustic in purpose of getting final result and intermediate data. Those data are important for reporting to the certificating authority.

343-353

Authors: Batinić Vojislav

This paper presents methodological approach to calculation of natural frequencies and modal shapes by using of finite elements method. Modal analysis realized by application of finite elements method, results by the rule, in a large number of modal shapes (frequencies) of natural oscillation. In real conditions only some of them are excited. The main purpose of this paper is calculation of natural frequencies that we can recognize design effort and solutions for hindering of modal oscillation.