Univerzitná knižnica - Vedecké odborné časopisy
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Item Technológ - celé číslo 2/2025(University of Žilina, 2025)Item Vplyv geometrie reznej hrany na tvorbu triesky a zložky reznej sily(University of Žilina, 2025) Mičietová, Anna; Čilliková, MáriaThis paper deals with influence of cutting edge geometry on chip formation and components of cutting force components. The insert with the flat surface is compared with the insert containing positive geometry in order to produce acceptable chip form. It was found that cutting forces components are lower for the insert having positive geometry together with the lower energy consumed for chip formation. Furthermore, the acceptable chips in the form of short sequence is developed as contrasted against the insert of flat surface producing long chips. The measured cutting force components are decomposed in order to distinguishes between the components associated with chip formation and energy consumed in the produce new surface. Chip ratio for the flat insert is more and the shearing angle is therefore less.Item Giga casting ako technologická revolúcia vo výrobe automobilov(University of Žilina, 2025) Bolibruchová, DanaGiga casting is referred to as a technological revolution in automobile manufacturing. Large aluminium castings are increasingly used for the production of automotive vehicles, especially for electric vehicles with low weight and to reduce production costs. Since most of them are structural components loaded quasi-statically, dynamically and cyclically, the quality and quantifiable performance of extremely large aluminium castings is crucial for their production. This article briefly analyses the current state of the art in the field of giga castings, some examples of their use in the automotive industry, their benefits and advantages.Item Opotrebenie strižníkov a ich ostrenie(University of Žilina, 2025) Moravec, Ján; Melo, BorislavThe paper focuses on the issue of shear wear. Theoretical foundations are presented and an analysis of the issue of sharpening the active parts of the shear tool is also described. Sharpening the shears themselves is an important part of repairing shear tools and their required starting position before setting them on the press.Item Analýza stavu povrchu po shot peenovaní duplexnej ocele AlSi 318(University of Žilina, 2025) Neslušan, Miroslav; Florková, ZuzanaThis paper deals with surface integrity and the corresponding stress state as well as surface topography after shot peening of duplex steel AlSi 318 under the variable shot-peening conditions such as number of passes and applied air pressure. It was found that the energy of shot impacts is consumed mainly by austenitic phase whereas the ferritic one is less affected. High magnitude of residual stresses is developed under the higher number of cycles as well as for the higher media pressure. Amplitude of compressive residual stresses in austenite is more as that for ferrite one. Surface roughness is decreasing along with the number of shot peening cycles and the typical crater-like surface is produced.Item Ultrazvuková kontrola zvarov na železných materiáloch s hrúbkou do 8 mm(University of Žilina, 2025) Koňár, RadoslavThe paper deals with the possibilities of inspecting butt welds on steel materials with a wall thickness of up to 8 mm using phased array ultrasonic technology. The possibility of using ultrasonic technology also for materials with a wall thickness of up to 8 mm will allow in practice the extension of ultrasonic inspections to welds that are currently inspected only by the x-ray method. Ultrasonic inspection could fully replace the x-ray test, thereby increasing the efficiency and flexibility of NDT inspections in the construction of steel structures.Item Analýza tribologických vlastností kompozitného materiálu PA66+GF25(University of Žilina, 2025) Bronček, Jozef; Drbúl, Mário; Čuchor, Dávid; Madaj, RudolfThe aim of experiments was to acquire the knowledge that can be used in designing materials for bearing cages. The current trend is that leading bearing manufacturers are replacing metal cages in bearing construction with glass fiber (GF) reinforced polyamide (PA) cages. Experimental measurements were realized on the experimental device linear microtribometer working on the principle of method ball on plane. This method according to the standard ISO 7148-2 is standard method for tribological properties testing. The structure analysis of experimental samples was performed because of understanding of potential structure influence on material properties.Item Vplyv precipitačného vytvrdzovania na mechanické vlastnosti nehrdzavejúcich ocelí(University of Žilina, 2025) Kantoríková, ElenaThe article aims to highlight the impact of heat treatment - precipitation hardening on stainless steels. Precipitation hardening allows to achieve very high mechanical properties (tensile strength and yield strength), often significantly higher than in classical austenitic or ferritic steels. The aim is to compare the theoretical conditions of heat treatment and thus increase awareness of its advantages.Item Analýza a výber batériových systémov pre nezávislú elektrickú trakciu v železničnej doprave(University of Žilina, 2025) Samaš, Vladimír; Bučko, Martin; Adamkovič, MatúšThe increasing emphasis on environmental sustainability in rail transport is leading to a search for alternatives to conventional diesel rolling stock, especially on non-electrified or partially non-electrified local lines. Battery traction electric systems represent one of the prospective options, with their efficiency largely dependent on the choice of appropriate battery technology. Range optimization in this context means achieving the maximum possible distance a vehicle can travel on a single charge, considering weight, power and operating conditions, which tend to be variable during operation. An important aspect is also the analysis of the production and operating costs depending on the lifetime of the different battery types. In this paper, four main types of batteries usable in rail transport are compared - Li-ion (conventional lithium-ion), LiFePO₄ (LFP), Li-Titanate (LTO) and Lithium Polymer (Li-po). They are compared in terms of technical parameters (energy density, voltage, cycling life), cost effectiveness, safety and suitability for railway applications. The analysis also includes an assessment of the potential of sodium-ion (Na-ion) batteries as a future alternative.Item Kvantitatívne hodnotenie náchylnosti Al-Si-Cu-Mg zliatiny s prídavkom titánu na vznik trhlín za tepla(University of Žilina, 2025) Sýkorová, MartinaThis study presents a quantitative evaluation of the effect of titanium (Ti) additions on the hot-tearing susceptibility of the AlSi5Cu2Mg aluminium alloy. The AlSi5Cu2Mg aluminium alloy is used in the production of highly stressed cylinder head castings and is characterized by an increased susceptibility to hot tears. The main objective of the study was to determine the extent to which grain refinement of the aluminium alloy with an excessive amount of Ti affects its susceptibility to hot tears. Thermal analysis was performed to characterize the solidification behaviour of the experimental alloys. Grain refinement was evaluated metallographically by measuring the Dendrite Arm Spacing (DAS) index. The results confirmed that the addition of titanium led to a decrease in the hot tearing susceptibility of the AlSi5Cu2Mg alloy.