Applied Mechanics and Materials Vol. 791

Abstract: This paper presents results of personal research concerning designing a new construction in the form of axially symmetric ducts, characterized by a complex construction of the carrying wall. These ducts were designed so that in the carrying wall they have a specified number of micro canals, in which additional cables can be placed. This paper presents research results of selected mechanical properties of the products, the values of force required to achieve a deformation of 3%, useful to calculating the peripheral stiffness of the construction. The research results allowed to determine the range of change of thinning possibility of the wall of the product in relation to the volume of the material and the mathematical function depicting the outline of the duct in cross-section.

Abstract: By changing a air flow rate of the two-phase (air-water) flow through a minichannel weidentified aggregation and partitioning of air bubbles and slugs of different sizes and air bubble arrangement into periodic patterns. The identification of these spatio-temporal behaviour was doneby digital camera. Simultaneously, we provide the detailed studies of these phenomena by using thecorresponding sequences of light transmission time series recorded by a laser-phototransistor sensor.To distinguish the instabilities in air slags and their breakups and aggregations we used the Fourierand multiscale entropy analysis.

Abstract: The paper presents a comparative analysis of static shear strength of single-lap adhesive joints of 316L steel, before and after mechanical treatment with a coated abrasive tool. The research was of comparative nature and focused on adhesive joints subjected to variable thermal stress and adhesive joints not subjected to such shock. Adhesives based on epoxy resins were used. The results of static shear strength tests of single-lap adhesive joints for different variations of material preparing were analysed. The obtained results were analysed statistically and in compliance with relevant scientific standards. The scope of tests covered a relatively short fatigue cycle, i.e. 200 cycles in the range of temperatures between-40°C and +60°C. The main aim of the research was to determine the relation between joint strength and thermal fatigue. The paper presents conclusions resulting from the conducted research.

Abstract: After milling process burrs can form as a result of plastic deformation of the material. Wire brushing can be used as a fully automated method of deburring on machining centres. In order to provide the same effects after brush change it is important to precisely determine the tool diameter. The article presents the method of dynamic diameter determination of circular brushes, which is the diameter of the brush during rotation.

Abstract: A machining station, working together with a lathe, was designed and constructed for the stabilisation of the axis of low-rigidity parts in the process of machining. The basic element is a self-centring lunette with hydraulic drive, allowing part centring without any preliminary alignment. The methodology of calculation of the parameters of the “semi-finished product/supports” subsystem is given. The effect of various schematics of support arrangements on the dynamics of the semi-finished product was analysed. The analysis of schemes of low-rigidity part fixing in the device for the stabilisation of its axis was conducted with the method of initial parameters. The choice of supports and the positioning of backstays and/or buffering steady rests was also analysed for increasing the stationary character of the process of machining and the quality of shaping the machined surface.

Abstract: Recently the laser beam treatment is more and more in common practice. The fields of use are very diverse. One of these fields of activity is removing of pollutions from a surface and preparation of it before the next stage of treatment. In the paper are presented the results of experimental research which were conducted in the aim of assessment of effects after cleaning of AISI 4130 steel by laser beam. The indicator of process quality was surface free energy (SFE) which is well known indicator in the operation where adhesion is very important. To its assess the measurement of wettability angle is required. After the experiment the results show that it is possible to improve the energetic state of the surface, thus the better preparing of surface before activity when the good adhesion properties are needed than in the case of traditional manner of treatment.

Abstract: The paper reports the results of model testing of dry and mixed friction wear of a worm – worm rack kinematic pair, where the worm is made of CUA19Fe3 bronze, while the rack of alloy cast iron. Such a pair is applied in the feed mechanisms of heavy-duty machine tools. The experiment was conducted with variable cast iron hardness values and pressure levels. The distribution of wear along the friction path for the both elements of the tribological pair has been determined. The results are presented in diagrams and in the form of a relationship of wear intensity as a function of the parameters examined in the experiment.

Abstract: The paper presents the main methods of surface free energy calculation of solids based on the contact angle measurement. The basic of splitting the surface free energy into components as well as interactions at the solid-liquid boundary phase considered while developing calculation models were presented. Basing on test results of surface free energy of 0H18N9T stainless steel, the relation between the method of surface preparation and the surface free energy were shown. The analysis focuses on change of the polar part. Differences between methods were indicated and it was pointed that skipping the polar component in analysis of adhesive joints strength results in deterioration of prediction model.

Abstract: In article has been presented machining process mathematical model of elastic-deformable shafts. It has been presented problem of optimal regulation of technological system in automated production systems too.

Abstract: Involute spur gears are manufactured by various technologies, the most common of which is the hobbing method. They are cut with special tools, in general on special machine tools. The article presents the principles of the technology of machining gears by the step-by-step method on universal CNC machine tools. The tool used is a ball-end finger-type mill, whose geometry is not associated with the geometry of the toothing being cut. The developed technology enables the longitudinal modification of the tooth profile. It can be useful especially in the machining of gears in piece production and large-module gears with tooth modification. These gears are insensitive to assembly errors.