Structural optimization of journal porous metal bearing

Proizvodnja i istraživanje samopodmazujućih kliznih ležaja su u stalnoj ekspanziji zbog svoje osobine da su pogodna za održavanje i imaju dug radni vek. Ovo je verovatno veoma važan razlog za njihovu uobičajenu upotrebu kod većine savremenih mašina i mehanizama, gde porozni klizni ležaji zauzimaju lidersku poziciju. Sa novim metodama simulacije i softverskim alatima moguće je sačiniti kvalitativne analize ponašanja kliznih ležaja, uzimajući u obzir njihove elastične deformacije. U ovom radu predstavljena je strukturalna optimizacija radijalnih poroznih kliznih ležaja koji su složeno opterećeni. Kao opterećenje na unutrašnjoj površini poroznog kliznog ležaja uzeta je raspodelom pritiska izračunata po hidrodinamičkoj teoriji podmazivanja. Pored toga postoji i sila trenja klizanja, kao i neravnomerna raspodela temperatura po zapremini ležaja, koje takođe treba uzeti u obzir. Strukturalna analiza je urađena za svako od navedenih opterećenja pojedinačno, kao i za složeno opterećenje ovih ležaja. Analiza je obavljena metodom konačnih elemenata (MKE) u modulu za strukturalnu analizu softvera CATIA V5R11. Na osnovu rezultata ove analize u drugom delu rada je data parametarska optimizacija poroznog kliznog ležaja, uzimajući u obzir elastične deformacije čaure ležaja. Simulacije, analize i optimizacija, koje su realizovane pomoću CATIA V5R11 su u ovom radu predstavljene i ilustrovane odgovarajućim slikama i dijagramima.Selflubricating sliding bearings production and investigations are still in great expansion because of their very practical maintenance and very long operating life. This is probably a very important reason for their common use in most of modern machines and mechanisms, where porous metal bearings take a leader position. With some new simulation methods and software tools it is possible to make qualitative analysis of sliding bearing behavior taking elastic deformations in account. This paper presents structural optimization of journal porous metal bearing under complex load distribution. Surface of porous metal bearing is loaded inside with pressure distribution that is calculated by hydrodynamic lubrication theory. Besides, there is also frictional force loading inner surface and nonuniform temperature distribution on bearing volume. The structure analysis is made for each kind of load separately and for complex load distribution of bearing. This analysis is realized by finite elements method (FEM) in structure analysis module of CATIA V5R11 software. Based on analysis results, in the second part of the paper is given parameter optimization of porous metal bearing with taking elastic deformations of bearing shell into account. These simulations analysis and optimizations realized in CATIA are covered and illustrated with corresponding pictures and diagrams

Structural optimization of journal porous metal bearing

Proizvodnja i istraživanje samopodmazujućih kliznih ležaja su u stalnoj ekspanziji zbog svoje osobine da su pogodna za održavanje i imaju dug radni vek. Ovo je verovatno veoma važan razlog za njihovu uobičajenu upotrebu kod većine savremenih mašina i mehanizama, gde porozni klizni ležaji zauzimaju lidersku poziciju. Sa novim metodama simulacije i softverskim alatima moguće je sačiniti kvalitativne analize ponašanja kliznih ležaja, uzimajući u obzir njihove elastične deformacije. U ovom radu predstavljena je strukturalna optimizacija radijalnih poroznih kliznih ležaja koji su složeno opterećeni. Kao opterećenje na unutrašnjoj površini poroznog kliznog ležaja uzeta je raspodelom pritiska izračunata po hidrodinamičkoj teoriji podmazivanja. Pored toga postoji i sila trenja klizanja, kao i neravnomerna raspodela temperatura po zapremini ležaja, koje takođe treba uzeti u obzir. Strukturalna analiza je urađena za svako od navedenih opterećenja pojedinačno, kao i za složeno opterećenje ovih ležaja. Analiza je obavljena metodom konačnih elemenata (MKE) u modulu za strukturalnu analizu softvera CATIA V5R11. Na osnovu rezultata ove analize u drugom delu rada je data parametarska optimizacija poroznog kliznog ležaja, uzimajući u obzir elastične deformacije čaure ležaja. Simulacije, analize i optimizacija, koje su realizovane pomoću CATIA V5R11 su u ovom radu predstavljene i ilustrovane odgovarajućim slikama i dijagramima.Selflubricating sliding bearings production and investigations are still in great expansion because of their very practical maintenance and very long operating life. This is probably a very important reason for their common use in most of modern machines and mechanisms, where porous metal bearings take a leader position. With some new simulation methods and software tools it is possible to make qualitative analysis of sliding bearing behavior taking elastic deformations in account. This paper presents structural optimization of journal porous metal bearing under complex load distribution. Surface of porous metal bearing is loaded inside with pressure distribution that is calculated by hydrodynamic lubrication theory. Besides, there is also frictional force loading inner surface and nonuniform temperature distribution on bearing volume. The structure analysis is made for each kind of load separately and for complex load distribution of bearing. This analysis is realized by finite elements method (FEM) in structure analysis module of CATIA V5R11 software. Based on analysis results, in the second part of the paper is given parameter optimization of porous metal bearing with taking elastic deformations of bearing shell into account. These simulations analysis and optimizations realized in CATIA are covered and illustrated with corresponding pictures and diagrams

Up-to-date tribology equipment for standard qualification of greases

Tribotesting of greases as a range of standardised procedures, which are complementary to laboratory analyses of physicochemical grease properties, is in some cases conducted, using classical tribometers, but generally requires more specific techniques complying with the standard qualification procedures recognised for years by major manufacturers of greases and bearings. The authors concentrate on the popular range of upto- date equipment for grease testing, including some disadvantages in the older constructions, and the novelties of the new designs, eliminating any inconsistency between the requirements of the standards (DIN, ISO, ASTM, etc.) and the tribological conditions with the goal of providing a reliable adequateness between the real conditions in the machinery and those in the test rigs

Up-to-date tribology equipment for standard qualification of greases

Tribotesting of greases as a range of standardised procedures, which are complementary to laboratory analyses of physicochemical grease properties, is in some cases conducted, using classical tribometers, but generally requires more specific techniques complying with the standard qualification procedures recognised for years by major manufacturers of greases and bearings. The authors concentrate on the popular range of upto- date equipment for grease testing, including some disadvantages in the older constructions, and the novelties of the new designs, eliminating any inconsistency between the requirements of the standards (DIN, ISO, ASTM, etc.) and the tribological conditions with the goal of providing a reliable adequateness between the real conditions in the machinery and those in the test rigs

Zloupotreba znanja - bioetička i bezbednosna pitanja vezana za sintetičku biologiju

The design and construction of new biological systems in the way engineers design electronic or mechanical systems is the primary goal of synthetic biology. The ability to create and modify life forms and easy access to information to do so has raised a number of issues related to ethics and security. In the era of rapid development of biotechnology, and the perception of the consequent risks to the environment and health, the ethics of knowledge becomes a matter of practical significance. The concern about the misuse of knowledge from synthetic biology influences new risk reduction strategies, which can have significant effects on scientific progress. This paper will provide an overview of the main bioethical and biosafety issues of synthetic biology.Projektovanje i izgradnja novih bioloških sistema na način kako inženjeri dizajniraju elektronske ili mehaničke sisteme je primaran cilj sintetičke biologije. Sposobnost stvaranja i modifikacije životnih oblika i lak pristup informacijama kako to učiniti, pokrenula je brojna pitanja vezana za etiku i bezbednost. U doba brzog razvoja biotehnologije, i uviđanja posledičnih rizika po životnu sredinu i zdravlje, etika znanja postaje stvar od praktičnog značaja. Zabrinutost zbog zloupotrebe znanja iz sintetičke biologije utiče na nove strategije za smanjenje rizika, a što može imati značajne efekte na naučni napredak. Ovaj rad će dati pregled glavnih bioetičkih i biosigurnosnih pitanja sintetičke biologije

Tribology in Ballroom Dance With Energy Consumption Analysis

Tribology phenomena are obviously present and have significant importance in most of human activities, processes and actions. Ballroom Dance as a common activitie with practically importance is not enough studied and analyzed from the tribological point of view. This paper presents an attempt in this direction dealing with study of tribology aspects by analyzing a couple of Standard and Latin ballroom dances with characteristic steps and choreography. This paper shows an approximate calculation of friction forces and torques caused by some common movements and their influence on interaction in foot floor interface. Besides the approximate calculation of friction loss, authors have measured and analyze the total energy consumption by making several experiments with corresponding equipment

Tooth flanks scoring resistance of non-involute teeth profiles in plane toothed cylindrical gears

Rad prikazuje rezultate teorijskih i eksperimentalnih istraživanja otpornosti na zaribavanje bokova zubaca cilindričnih zupčanika sa konveksno-konkavnim oblicima profila zubaca. Postoje opšti osnovni izrazi, zasnovani na temperaturnom kriterijumu, koji su primenljivi za sve zadate oblike kontaktnih površina bokova zubaca cilindričnih zupčanika. Izrazi koji su dobijeni na osnovu teorije su ilustrovani rezultatima ispitivanja na zaribavanje prema FZG metodi ispitivanja zupčanika na uređaju sa zatvorenim kolom snage (DIN 51354).The paper presents results of theoretical and experimental research into the scoring resistance of plane convex-concave gears. There are generalized basic relations of the integral temperature criterion for all kinds of path of contact in defined plane cylindrical gears given. Theoretically obtained relations are illustrated by the results of the scoring tests according to the FZG method (DIN 51354)

Wear simulation of the polymer based composite sliding bearings by means of ansys

Polymer based composite sliding bearings are increasingly applied in many industries, due to their economic (usually low cost of production) and technical (good tribological properties) benefits. In order to predict their life cycle, it is necessary to perform numerous experiments and evaluate their wear rate. This is generally quite expensive and time consuming. By applying only one series of the experiments and determining Archard’s wear coefficient, and embedding it into the code of the Ansys software, it is possible to simulate the wear, and thus save the time and the financial resources. This paper explains the procedure of the wear simulation in case of known Archard’s coefficient, for sliding bearings made of PTFE polyamide composite material in contact with shaft of steel. The output of the simulation is the contact pressure in relation of time and the amount of worn volume for 3 revolutions of the shaft