Vrednovanje zaostalih naprezanja u zavaru metodom bušenja otvora

Residual stresses arise in the structures without loading during the technological processes, e.g. casting, rolling, welding, and pressing. In the paper is described the process of quantification of residual stresses by the hole-drilling method. For determination of residual stresses were used the procedures in which are supposed constant or linear distributions of stresses along the hole.Zaostala naprezanja nastaju u neopterećenim izradcima tijekom tehnoloških procesa, npr., pri odlijevanju, valjanju, zavarivanju i prešanju. U članku je opisan postupak vrednovanja zaostalih naprezanja u zavarenom spoju primjenom metode bušenja otvora. Za određivanje zaostalih naprezanja rabljen je postupak u kojemu se predmnijeva stalna ili linearna raspodjela naprezanja duž otvora

Vrednovanje zaostalih naprezanja u zavaru metodom bušenja otvora

Residual stresses arise in the structures without loading during the technological processes, e.g. casting, rolling, welding, and pressing. In the paper is described the process of quantification of residual stresses by the hole-drilling method. For determination of residual stresses were used the procedures in which are supposed constant or linear distributions of stresses along the hole.Zaostala naprezanja nastaju u neopterećenim izradcima tijekom tehnoloških procesa, npr., pri odlijevanju, valjanju, zavarivanju i prešanju. U članku je opisan postupak vrednovanja zaostalih naprezanja u zavarenom spoju primjenom metode bušenja otvora. Za određivanje zaostalih naprezanja rabljen je postupak u kojemu se predmnijeva stalna ili linearna raspodjela naprezanja duž otvora

Quantification of Residual Stresses in Hot Rolled Steel Sheets by the Hole Drilling Method

The paper deals with the problems of quantification of residual stresses in hot rolled sheets produced under various regimes. On the base of stress distribution along width and thickness of the belt is pointed out on possibilities of belt deformation from the plane as a result of action of torsional moment as an integral internal quantity in cross-section. For the non-uniformly distributed stresses along the thickness of the sheet the new method for residual stresses determination was developed. Application of the method is described in the paper

Increasing of Reliability of Converter

The innovative activities in steel production invoke exploitation of new machines with the higher production capacity and productivity of labor. The paper deals with deformation and stress analysis of carrying parts of converter pedestal on the base of which the proposals and supporting measures were made that had the aim to increase reliability of the converter during steel production. This was achieved by lifespan prolongation of anchor and connecting bolts of converter pedestal, by change of stiffness of connected elements as well as by correction of nuts of bolted connections. The realization of structural changes decreased loading amplitudes and consequently the vibrations of pedestal. Solution was verified by numerical and experimental procedures of mechanics

The Strain Gage Method for Determination of Input Working Life Parameters of Pipes in Compressor Stations

For determination of safety operation of compressor stations and assessment of their residual working life is necessary to know the levels of residual stresses, operational loading as well as functionality of real support elements and influence of history of previous loading. The method described in the paper was verified several times during solution of problems concerning safety operation of piping yards. The method was also verified by the numerical methods of mechanics

Application of photostress method in stress analysis of a rotating disc

The presented article demonstrates the application of PhotoStressR method in stress analysis of a rotating disc of a constant thickness, which was made of a photoelastic material PS-1A. Isoclinic fringes were observed on the rotating disc using linear polarized light at revolutions 5 000 RPM. Observations were carried out under angle parameter 0 o to 90 o with 10 o increase. A set of isostatic lines of I and II set was made from the set of obtained isoclinic lines. During gradual increase of rotations of the rotating disc up to 17 000 RPM, and with circular polarized light, we observed the distribution of colourful isochromatic fringes on the rotating disc. The field of isochromatic fringes, gained experimentally, at 15 000 RPM was compared with the field which was gained by means of a numerical analysis

Numeričko i eksperimentalno modeliranje nosivih elemenata teške metalurške opreme

Carrying structures of heavy metallurgical equipments are during their operation often exposed to extreme loading. The short-term overloading of the structure results to high stresses in locations of their concentrations. By repeating of these phenomena is decreased the life-time of the structure and eventually this leads to local failures in their carrying elements. In the paper are on examples described advantages of using numerical and experimental methods of mechanical system modelling that is exploited for identification of overloading in carrying elements of metallurgical equipments or for detection of damage causes.Nosivi elementi teške metalurške opreme tijekom eksploatacije često su izloženi ekstremnim opterećenjima. Njihova kratkotrajna preopterećenja izazivaju visoka naprezanja na mjestima koncentracije. Ponavljanje ove pojave izaziva skraćenje životnog vijeka konstrukcije i moguća lokalna oštećenja nosivih elemenata. U ovom članku, na dva primjera su prikazane prednosti primjene numeričkih i eksperimentalnih metoda modeliranja mehaničkog sustava u otkrivanju preopterećenja ili uzroka oštećenja nosivih elemenata metalurške opreme