Ukrainian Journal of Mechanical Engineering and Materials Science. – 2019. – Vol. 5, No. 1

Permanent URI for this collectionhttps://ena.lpnu.ua/handle/ntb/49612

Науковий журнал

Засновник і видавець Національний університет «Львівська політехніка». Виходить двічі на рік з 2015 року.

Ukrainian Journal of Mechanical Engineering and Materials Science = Український журнал із машинобудування і матеріалознавства : науковий журнал / Lviv Politechnic National University ; editor-in-chief Oleksiy Lanets . – Lviv : Lviv Politechnic Publishing House, 2019. – Volume 5, number 1. – 104 p.

Український журнал із машинобудування і матеріалознавства

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Content (Vol. 5, No 1)


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    Substantiation of structure and parameters of pneumatic system of mobile robot with orthogonal walking drive
    (Видавництво Львівської політехніки, 2019-03-20) Korendiy, Vitaliy; Zinko, Roman; Muzychka, Diana; Lviv Polytechnic National University; Dniprovsky State Technical University
    Problem statement. Mobile robots have awoken a large interest between scientists and designers in the last few years. One of the prospective drives of such robots is based on pneumatically operated system with no use of electric, heat, magnetic or other types of energy. Purpose. The main purpose of this research consists in substantiation of structure and parameters of pneumatic system of mobile robot with orthogonal walking drive. Methodology. The research is carried out using the basic laws and principles of mechanics, pneumatics and automation. The numerical experiment is conducted in MathCAD software and computer simulation of the robot’s motion is performed using SolidWorks software. Findings (results) and originality (novelty). The improved structure of the mobile robot with orthogonal walking drive is proposed. The pneumatically operated system ensuring the robot’s motion is substantiated. Practical value. The proposed design of walking robot can be used while designing industrial (production) prototypes of mobile robotic systems for performing various activities in the environments that are not suitable for using electric power. Scopes of further investigations. While carrying out further investigations, it is necessary to ensure the possibility of changing motion direction of mobile robot by means of pneumatic drive. In addition, it is expedient to design the devices for changing motion speed of the robot and the height of lifting of its feet.
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    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 Ukraine
    Stress 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.