http://arthra.ugal.ro/handle/20.500.14043/25256 Tue, 07 Apr 2026 16:54:50 GMT 2026-04-07T16:54:50Z http://arthra.ugal.ro/handle/20.500.14043/25280 Research on Surface Roughness by Laser Cut Radovanovic, Miroslav; Dašić, Predrag Laser cutting is one of the most industrial applications. Laser cutting with oxygen is used primarily for cutting of mild and low-alloyed steels. Cut surface quality is a very important characteristic of laser cutting that ensures an advantage on other contour cutting processes. This paper gives results of the experimental research referring to the determination of surface indicators obtained by laser cutting. The relationships between roughness parameters are given by linear and exponential equations. THE ANNALS OF UNIVERSITY “DUNĂREA DE JOS “ OF GALAŢI FASCICLE VIII, 2006 (XII), ISSN 1221-4590 TRIBOLOGY Sun, 01 Jan 2006 00:00:00 GMT http://arthra.ugal.ro/handle/20.500.14043/25280 2006-01-01T00:00:00Z http://arthra.ugal.ro/handle/20.500.14043/25279 Etablissement de L’angle Maximum de Pivotement pour un Rouleau Cylindrique d’un Roulement a Quatre Epaulements de Guidage Paleu, Viorel; Nelias, Daniel; Antaluca, Dominic; Mevel, Bruno In cylindrical roller bearings subjected to complex radial and axial load, there is always a skew motion of rollers. This parasite motion increases the total friction loss within the bearings, restricting their running speed and life. The actual skew angle of a roller is attended by equilibrium of forces and moments acting on that roller, but this angle can be limited by the geometry of guiding flanges and cage pocket. In this paper, the limiting skew angle of rollers is estimated for a cylindrical roller bearing with four guiding flanges and a complex roller profile. The influence of different geometrical parameters (flange angle, threshold flange height, and roller to cage pocket radial clearance) on the limiting skew angle of roller is also presented. THE ANNALS OF UNIVERSITY “DUNĂREA DE JOS “ OF GALAŢI FASCICLE VIII, 2006 (XII), ISSN 1221-4590 TRIBOLOGY Sun, 01 Jan 2006 00:00:00 GMT http://arthra.ugal.ro/handle/20.500.14043/25279 2006-01-01T00:00:00Z http://arthra.ugal.ro/handle/20.500.14043/25278 Prediction of Wear of Acetabulum Inserts Due to Multiple Human Routine Activities Onișoru, Justin; Capitanu, Lucian; Iarovici, Aron It is difficult to predict the quantitative and qualitative aspects of the wear of the components that allow relative motion due to several factors. First, the prosthetic parts in contact experience a wide spectrum of loadings induced by the large domain of common activities. Secondary, the contact conditions evolve due to wearing, a long-time prediction implying a high level of nonlinearity. The authors tried to overcome all these difficulties using a complex predictive model that combines statistical evaluation, nonlinear mechanical analyses of load transfer by the contact interface and tribological estimations of the wear characteristics. After a theoretical description of the predictive model, one could notice an application for an artificial hip joint – a frictional titanium alloy on UHMWPE couple. Several loading regimes are considered as characterised in [1]. For every regime a dynamic Finite Element simulation of the dry-friction contact was performed establishing the contact traces and the contact pressure distribution. Those characteristics combined with the frequencies of the activities considered (as determined in [2]) are input data for a statistical evaluation of the joint loading during some period. Developing an original method the authors could evaluate the volume of wear debris across different activities based on the joint load transfer characteristics specific to each activity. THE ANNALS OF UNIVERSITY “DUNĂREA DE JOS “ OF GALAŢI FASCICLE VIII, 2006 (XII), ISSN 1221-4590 TRIBOLOGY Sun, 01 Jan 2006 00:00:00 GMT http://arthra.ugal.ro/handle/20.500.14043/25278 2006-01-01T00:00:00Z http://arthra.ugal.ro/handle/20.500.14043/25277 Ultrasound Action on Strength Properties of Polycrystalline Metals Moraru, Luminița The mechanical properties of pure aluminum were investigated by tensile test on the sample with average grain size between 60 and 1000 µ m. The stress strain functions given by the models are fitted to the measured points. The grain size dependence on the uniform yield stress was studied. In order to put in evidence the effect of ultrasonic field on grain size, the measurements were carried out for samples solidified under similar conditions both with and without sonication. For pure aluminium, the author quantitatively evaluated the validity of Hall-Petch model. THE ANNALS OF UNIVERSITY “DUNĂREA DE JOS “ OF GALAŢI FASCICLE VIII, 2006 (XII), ISSN 1221-4590 TRIBOLOGY Sun, 01 Jan 2006 00:00:00 GMT http://arthra.ugal.ro/handle/20.500.14043/25277 2006-01-01T00:00:00Z