|
|
NAUČNOSTRUČNI I INFORMATIVNI ČASOPIS ZA OBLAST TEHNIČKE DIJAGNOSTIKE U TEHNIČKIM I SRODNIM DISCIPLINAMA
|
||
|
SADRŽAJ
1Faculty of Natural Sciences and Engineering, University of Ljubljana, Slovenia FAILURES AND CRACK FORMATION AKTIVNE SNAGE I FREKVENCIJE USPEŠNOSTI PROIZVODA OD GUME PROGRAMIRANJA SA OGRANIČENJIMA
|
CONTENTS 1Faculty of Natural Sciences and Engineering, University of Ljubljana, Slovenia | ||
|
REZIME - ABSTRACT
1. Prof. Dr. Borut Kosec1 Prof. Dr. Mirko Soković2 Dr. Gorazd Kosec3 1Faculty of Natural Sciences and Engineering, University of Ljubljana, Slovenia
INFLUENCE OF INITIAL DIE-CASTING DIE TEMPERATURE TO THE FAILURES AND CRACK FORMATION
ABSTRACT Die-casting is the most cost efficient and technical easy method of casting sophisticated and accurate aluminium alloys parts in great-scale series. Die-castings require little machining prior the final installation. In engineering praxis die-casting dies for casting of aluminium alloys fail because of a great number of different and simultaneously operating factors. Material selection, die design, and thermal stress fatigue generated by the cyclic working process, as well as to low and inhomogeneous initial die temperature contribute to the failures and cracks formation on/in dies.
2. Dr Miodrag Kušljević TERMOELEKTRO ENEL AD, Uralska 9, Beograd
ADAPTIVNI REKURZIVNI ALGORITAM ZA MERENJE FUNDAMENTALNE AKTIVNE SNAGE I FREKVENCIJE AN ADAPTIVE RECURSIVE ALGORITHM FOR SIMULTANEOUS FUNDAMENTAL ACTIVE POWER AND FREQUENCY ESTIMATION
REZIME U ovom radu je prikazana jedna rekurzivna metoda za istovremeno merenje osnovne frekvencije i aktivne snage ektroenergetske mreže u nesinusoidalnim uslovima i uz promenu frekvencije u širokom opsegu. Pretpostavljeno je da su signali napona i struje prostoperiodični. Adaptivni filteri sa konačnim impulsnim odzivom (finite-impulse-response – FIR) su korišćeni za izdvajanje fundamentalne komponente naponskog i strujnog signala i za smanjenje uticaja šuma. Zahvaljujući jednostavnosti matematičkog modela problem estimacije je transformisan u predeterminisan sistem linearnih jednačina. U cilju procene performansi algoritma izvršene su računarske simulacije i dati njihovi rezultati. Algoritam je pokazao visoki stepen robusnosti i visoku tačnost u širokom opsegu promene frekvencija. Predloženi algoritam je pogodan za primene u realnom
vremenu.
SUMMARY A new approach in the design of digital algorithm for simultaneous fundamental active power and frequency estimation of the local system under non-sinusoidal conditions and wide-range frequency deviations is presented. The pure sinusoidal voltage and current models were assumed. Adaptive finite-impulse-response (FIR) filters are used to decompose out the fundamental components of the input voltage and current signals and to minimize the noise effects. The most important point of the algorithm is a mathematical model which transforms the problem of estimation into an over determined set of linear equations. To demonstrate the performance of the developed algorithms, the results of computer simulations are presented. The algorithm shows a very high level of robustness, as well as high measurement accuracy, over a wide range of frequency changes. The algorithm convergence provided fast response and adaptability.
3.
Prof. dr Milivoj Klarin, Mašinski fakultet Univerziteta u Beogradu
SAVREMENE TENDENCIJE U UPRAVLJANJU ODRŽAVANJEM - PRISTUP ODRŽAVANJU ZASNOVAN NA RIZIKU ACTUAL MAINTENANCE MANAGEMENT TENDENCIES - RISK BASED MAINTENANCE
REZIME U radu su prikazani savremeni koncepti u upravljanju održavanjem tehničkih uredjaja,
opreme, instalacije i fabričkih
postrojenja. Izložene su ukratko karakteristike pojedinih metoda i strategija održavanja. Poseban akcenat stavljen je na upravljanje održavanjem zasnovano na riziku i analizirana je mogućnost uvodjenja ovog koncepta u druge industrijske segmente osim u procesnu, hemijsku, energetsku industriju što je i primarna oblast primene RBIM
koncepta.
ABSTRACT Actual management concepts for maintenance technical devices, parts, instalation and facilities are presented in this paper. Characteristics of certain methods and strategies are presentes. Focus of the paper is on maintenace management based on risk. Also, application of maintenance management based on risk in other industrial sector (beside petroloum, hemical, power plant industries as primary RBIM application domain) are discused.
4.
Dr Slavica Prvulović1,
PRIMENA PROMETHEE II - METODE U DIJAGNOSTICI USPEŠNOSTI PROIZVODA OD GUME
REZIME U radu su date osnovne teoretske postavke PROMETHEE metodologije, koja ima vrlo uspešnu primenu u procesu donošenja odluka kod višekriterijumskog odlučivanja. Izvršena je ilustracija praktične primene ove metode na hipotetičkom primeru izbora proizvoda tj.gume za automobile istih dimenzija a različitih
karakteristika, proizvodjača „TIGAT TYRES“ PIROT. Primenom PROMETHEE II metode izvršeno je rangiranje i doneta odluka o kupovini najisplativijeg proizvoda.
ABSTRACT This paper gives the basic aspects of multicriteria analysis and PROMETHEE methodology, which has successful usage in multicriteria decision making. Analysis was based on hypothetical example of customer decision making process during a purchase of new car tyre. The selection process was made among four types of tires equal dimension and same manufacture (“Tigar Tyres”-Pirot, Serbia), but with different driving characteristics.
5.
Prof. dr Živoslav Adamović Tehnički fakultet “Mihajlo Pupin”, Zrenjanin
MODELI ODRŽAVANJA NA BAZI TEHNIČKE DIJAGNOSTIKE
REZIME U radu su prikazana dva nova modela održavanja prema stanju i to: održavanje prema stanju sa kontrolom parametara i održavanje prema stanju sa kontrolom nivoa pouzdanosti. Dati su moduli razvijenih modela i analizirane etape razvoja. Razvijen je algoritam prognoze tehničkog stanja sistema.
ABSTRACT Two new maintenance models according to the condition are shown in operation, and those are: maintenance according to condition with parameters control and maintenance according to condition with control of the reliable levels. It was given modules developed models and analyzed stages of development. It was developed prognosis algorithm of the technical system condition
6. dr Đordje Dihovični, dipl. maš. inž. Viša tehnička škola,
ANALIZA PROSTIRANJA PNEUMATSKIH SIGNALA SA ASPEKTA RASPODELJENOSTI I KAŠNJENJA
REZIME Prenos pneumatskog signala u dugim vodovima je razmatran sa stanovišta raspodeljenosti, i vremenskog kašnjenja, i prezentovani su njihovi odskočni
odzivi. Korišćenjem Simulink modula programa Matlab efikasno je simuliran pneumatski sistem sa kašnjenjem. Prikazani su uporedni odskočni odzivi za oba fenomena, i utvrdjeno je da je brzina reagovanja sistema veća ukoliko se on razmatra sa stanovišta kašnjenja
ABSTRACT Transient in long pneumatic lines is considered from distributed parameter and as well time delay view of point, and are presented time responses. By using Simulink module of program Matlab, efficiency is simulated pneumatic system with time delay. There are presented time responses for both phenomena, and it is determined that system speed response is higher if the analyze is taking into account from time delay view of point.
7. Mr Miodrag Strak, dipl.inž.
Fakultet informacionih tehnologija, Beograd
PLANIRANJE RESURSA ODRŽAVANJA KORIŠćENJEM PROGRAMIRANJA SA OGRANIČENJIMA
REZIME Donošenje odluka vezanih za organizaciju održavanja,
često se odvija u uslovima ograničenog broja vrsta i ograničene količine različitih
resursa. Ograničena raspoloživost, takodje, stvara probleme u planiranju aktivnosti, što
često dovodi do nepovoljnog rasporedjivanja resursa u vremenu. U ovom radu prikazane su mogućnosti primene tehnika zasnovanih na ograničenjima. U toku razvoja ove tehnologije puno se radilo na razvoju i unapredjenju sistema zaključivanja. Izmedju
ostalog, rezultat tih napora koji se pokazao kao jedan od uspešnijih, jeste uvodjenje globalnih ograničenja. Od posebnog značaja je mogućnost implementacije globalnih ograničenja u savremenim objektno-orijentisanim programskim jezicima. U ovom radu razmatra se praktična primena globalnih ograničenja u Java programskom okruženju, za potrebe planiranja resursa održavanja jednog proizvodnog sistema.
ABSTRACT Decision making related with the maintenance planning is often performed in conditions of limited number of types and limited quantity of different resources. Limited availability, also, creates problems in activity planning which often leads to unfavorable resource allocation in time. In this work, application possibilities of constraint programming are shown. During the development of this technology, a great effort was put into the development and enhancing of the reasoning system. The result of this effort, which turned out to be one of the most successful, was introduction of the global constraints. The possibility of implementation of the global constraints in object-oriented programming languages is especially significant. This work deals with practical applications of global constraints in Java programming environment for the needs of resource planning for maintenance of a production system.
| |||
