Applied Engineering Letters

47-51

Authors: M. Vicen, P. Fabian, J. Bronček, M. Drbúl

The stresses in structural components can appear due to different reasons: loading, manufacturing long-time operations, etc. One of the reasons for stresses appearance is the heat treatment to which components sometimes need to be subjected. Changes in the size and shape of products are manifestations in the heat treatment. Although those changes are undesirable, they cannot be completely avoided and/or eliminated. This article deals with the effect of the heat treatment on change of the size of bearing rings. The aim was to compare the dimensions before and after the heat treatment, to find out whether the changes are within tolerance ranges or if the additional processing of components would be necessary. Another aim was to monitor the effect of layout of bearing rings on dimensions change.

63-71

Authors: I. Sovilj-Nikić, S. Sovilj-Nikić, B. Sovilj, I. Samardžić, D. Kozak, V. Blanuša

The problem of generating is analyzed in science and practice in various ways by identifying it once as an element of the machine, and the second time as a part of production, that is, a final product. The nature of the materials of the machine elements, the loads in the contact zone, the relative velocities, the topography of the contact surfaces, and the temperature in the contact zone influence on the tribological characteristics of the elements, and hence on the characteristics of the tribo-mechanical systems. The surfaces of the tribo-mechanical elements of the machines through which mutual contact is realized are essentially thin layers of materials whose composition and properties differ significantly from the properties of the basic mass element material. There are a significant number of tribo-mechanical systems in the energy sector. Gear cutting is the most important operation in the production of gears. The quality of the gear cutting is one of the conditions for achieving the required quality of the work-piece. The gear is an element of a large number of tribo-mechanical systems. The geometrical parameters of the hob milling, the accuracy of the profiling and the accuracy of manufacture significantly affect the productivity and machining costs. In this paper, the topography and roughness parameters of lateral back surfaces of the model hob milling tools are analyzed before and after cylindrical gear cutting.

78-83

Authors: N. Petrović, N. Kostić, N. Marjanović, V. Marjanović

The use of continuous variables for cross-sectional dimensions in truss structural optimization gives solutions with a large number of different cross sections with specific dimensions which in practice would be expensive, or impossible to create. Even slight variations from optimal sizes can result in unstable structures which do not meet constraint criteria. This paper shows the influence of the use of discrete cross section sizes in optimization and compares results to continuous variable counterparts. In order to achieve the most practically applicable design solutions, Euler buckling dynamic constraints are added to all models. A typical space truss model from literature, which use continuous variables, is compared to the discrete variable models under the same conditions. The example model is optimized for minimal weight using sizing and all possible combinations of shape and topology optimizations with sizing.