In the present work, functional properties of three different types of regular microreliefs, formed by ball burnishing process on flat surfaces are evaluated. For their estimation, heights and material ratio curve’s criteria were used, according to the international standard ISO 21920-2:2021. The influence of the regular relief’s type and ball burnishing process parameters on the surface functional properties were investigated using full factors experimental design. Based on the obtained results, statistical models were derived that describe the dependencies between the topography characteristics and the regular reliefs’ types and regime parameters of the ball burnishing process. Based on the obtained results, several conclusions have been formulated about the applicability of these standardized methods and criteria for evaluating the functional characteristics of the different types of regular reliefs at the end of the work.

The present work describes an experimental investigation of the fatigue durability of AISI 304 and AISI 316L austenitic stainless steels, which have regular reliefs (RR) of the IV-th type, formed by ball burnishing (BB) on flat surfaces, using a computer numerical control (CNC) milling center. The methodology and the equipment used for obtaining regular reliefs, along with a vibration-induced fatigue test setup, are presented and described. The results from the BB process and the fatigue life experiments of the tested austenitic stainless steels are gathered, using the approach of factorial design experiments. It was found that the presence of RR of the IV-th type do not worsen the fatigue strength of the studied steels. The Pareto, t-test and Bayesian rule techniques are used to determine the main effects and the interactions of significance between ball burnishing regime parameters. A stochastic model is derived and is used to find when the probability of obtaining the maximum fatigue life of parts made of AISI 304 or 316L reaches its maximum value. It was found that when the deforming force, the amplitude of the sinewaves and their wavenumber are set at high values, and the feed rate is set at its low value, the probability to reach maximum fatigue life for the parts made of AISI 304 or 316L is equal to 97%.

Ball burnishing process often applies for obtaining specifically characteristics in the surface layer of the functional surfaces of the machine parts. Using CNC machines for carrying out this process significantly increases the possibility of control the characteristics of the toolpath of the ball tool and thus to produce regularly distributed roughness with specific size and direction of cells alignment. The current study presents obtained results from L8 Taguchi experimental design for determining the significantly influenced parameters of the ball burnishing process carried out on CNC milling machine on the size and arrangement direction of the cells form regular distributed roughness on planar surfaces.

Mechanics courses traditionally characterize with a rather low percentage of passing students. Dynamic mathematical packages like GeoGebra are widely used nowadays for teaching mathematics, but its interactive capabilities can be used for simulation of different physical phenomena. In this article few interactive applets for Static, Dynamic, Strength of Materials and Theory of Mechanisms and Machines courses, are presented. An experiment with comparison of the test results of two group of students after the exercise beam about internal forces, shows that group trained with GeoGebra applets have significantly higher mean result.