Вісники та науково-технічні збірники, журнали
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Item Substantiation of the shape of a solid oxide fuel cell anode using the stress-strain and shape-dependent crack deceleration approaches(Видавництво Львівської політехніки, 2019-03-20) Kuzio, Igor; Vasyliv, Bogdan; Korendiy, Vitaliy; Borovets, Volodymyr; Podhurska, Viktoriya; Lviv Polytechnic National University; Karpenko Physico-mechanical Institute of the NAS of UkraineStress and strain distributions in the YSZ–NiO spheroidal shape anode-substrate for a solid oxide fuel cell (SOFC) under pressure of operating environment were calculated using the finite element analysis. The features were then compared with ones of the cylindrical shape anode. The radii ranges for the cylindrical and spheroidal (segments of a sphere) parts of the anode ensuring its improved deformation resistance and more uniform stress distribution were suggested. Based on the calculations, an anode of the cylindrical shape with top and bottom convex surfaces (a spheroidal shape anode), with the spheroid to cylinder radii ratio R / Rc in the range from 5 to 20 is suggested. Itsspecific volume V / Sc isin the range from 1 to 2.5 mm. The stressesin the most dangerous areas (i. e. along the axis and the closed-loop fixing) and maximum strain, caused by external gas pressure on the anode working surface, are decreased by 10–30 % and 20–40 % respectively as compared to an anode of the cylindrical shape of the same radius and volume features. This increases the lifetime of a solid oxide fuel cell. A three-dimensional curve of intersection of the surfaces of stress distribution in the anode along its axis and the closed-loop fixing was approximated which displays the values of balanced stresses depending on V / Vc and R / Rc parameters. Also, the advantage of the spheroid shaped SOFC anode-substrate over conventional flat one was substantiated using a shape-dependent crack deceleration approach.Item Substantiation of the process of vertical transportation of piece loads(Lviv Politechnic Publishing House, 2017-01-01) Nishchenko, Iryna; Borovets, Volodymyr; Lviv National Agrarian University, Dubliany, Ukraine; National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine; Lviv Polytechnic National University, Lviv, UkraineThe urgent problem of automatization of the process of products transportation with a help of vertical chutes under the influence of gravitational forces using elastic elements is considered. The interaction between the object being transported and the elastic elements is defined. Their mutual influence on the transportation speed is determined depending on the contact parameters. The analysis of the object transportation speed changing depending on friction and on the zone of their mutual contact is carried out.Item Synthesis of structure and research of operation of resonance two-mass vibrating table with electromagnetic drive(Publishing House of Lviv Polytechnic National University, 2015) Lanets, Oleksiy; Borovets, Volodymyr; Lanets, Olena; Shpak, Yaroslav; Lozynskyy, VasylAn industrial necessity of creation of 100-Hz vibratory tables is grounded. The prospect of researches of just resonance electromagnetic vibratory tables is conditioned. The existing vibrating tables on the basis of electromagnetic drive are considered. It is noted that the stages and problems which arise during the creating of high-frequency two-mass vibration table of middle sizes constructed according to classic chart are oulined in the article. The principle scheme of an electromagnetic vibratory table which is to be developed is described. The basic analytical dependences for determining the coefficient of inflexibility of the resonance resilient system and hauling effort of the electromagnetic vibroexciters are obtained. The construction of the upper plate of vibrating table is grounded, and its first eigenfrequency is determmined in order to avoid the coincidence with its forced frequency. The construction of vibrating table is given: its spatial model is presented, and the general draft and the draft of the two-mass vibratory system are also given. The inertia parameters of the oscillating masses are determined. The parameters of stiffness and structural parameters of the resonance resilient system are determined. Checking of the resilient elements for durability is conducted. The parameters of stiffness and structural parameters of vibration isolators are determined. The results of calculation of vibroexciter, according to the hauling effort with the use of the specially developed program, are presented. The theoretical gain-frequency description of vibratory table and time dependences of motion of the oscillating masses are presented. The experimental gain-frequency description of vibratory table and time dependences of motion of the oscillating masses, which absolutely coincide with the theoretical, are presented.