Wyniki wyszukiwania - Biblioteka Nauki

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Theoretical study of heat conduction in the multi-disc brake integrated into the drive wheel AGV during braking

100%

Varecha D. , Kohár R. , Lukáč M.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

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tom Vol. 69, nr 2

art. no. e136718

EN

This paper is focused on the theoretical study of heat conduction in the multi-brake system of the automated guided vehicle (AGV). The study aims to compare the amount of heat generated during braking from 10 m/s until a stop in a brake system based on organic and ceramic friction material. The theoretical study of heat conduction is solved in Matlab computational software using a derived Fourier partial differential equation for nonstationary heat conduction. The results of the simulation of the heat conduction are shown in the diagrams and indicate not only the temperature dependence in the period during braking from a speed of 10 m/s to a stop but also the amount of heat accumulated in the steel disc during braking. The simulation results show that braking in both brake systems generates approximately the same amount of heat. The difference occurs in the period of thermal activity, which was influenced by the length of the braking distance. This is caused by a coefficient of friction that significantly affects the final braking result. Finally, it can be stated that the brake system based on organic material must be equipped with a steel disc with a minimum thickness of 8 mm. This is because the brake system based on organic friction material has a set temperature limit of 160 degrees Celsius. The results presented in this study will help an engineer constructor to choose the right procedures and parameters of geometry for designing the mentioned braking system for the considered AGV.

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Design and optimization of the construction of a mobile disinfection chamber for small communication devices and small objects

88%

Galík J. , Varecha D. , Drbúl M. , Madaj R. , Konstantová V.

Production Engineering Archives

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2023

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tom Vol. 29, Iss. 2

201-215

EN

This manuscript aims to familiarise readers with the development of a device for the construction of a mobile disinfection chamber for small communication devices and small objects. The conceptual design and the material of the new device play essential roles in the design process of a new device. The manuscript presents concepts based primarily on previous experience and different perspectives. The concept design is created in the 3D modelling program CREO Parametric 8.0. A multi-criteria team evaluation determined the most suitable version of the idea. For dimensioning and shape adaptation of the device was used EinScan SP device (3D scanning method). The article's aim was also to establish a suitable way of producing a prototype using tribological research in available production methods and materials within rapid prototyping. Using the ALICONA Infinite Focus G5 device, experimentally investigated the parameters characterising the surface of the parts. The end of the manuscript focused on the mechanical structure and subjecting them to FEM analysis in the program ANSYS Workbench. The design of the concept disinfection device was also for extreme cases of use. Within this issue was optimising shapes, wall thicknesses, reinforcement design and other necessary modifications using the FEM analysis. From the results, the most suitable material to produce a more significant number of parts may not be the most suitable material to create prototype devices. Tools such as 3D scanning, rapid prototyping, and FEM analysis can "significantly" help reduce mistakes before testing the device.

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Research of Tribological and Thermodynamic Parameters of the WC-Cu Braking System of the Experimental Modular Electric Vehicle

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Varecha D. , Galik J. , Kohar R. , Gajdosik T. , Gajdac I. , Jenis J.

Production Engineering Archives

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2023

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tom Vol. 29, Iss. 2

116--127

EN

The authors of this manuscript present the development of a braking system with friction material baseWC-Cu coating for the electric vehicle. This manuscript follows on from the original development of an AGV multi-disc braking system and an experimental investigation of the friction factor of WC-Cu coatings. In addition to developing the mechanical elements and construction of the electric vehicle, the tribological parameters of three samples of the steel substrate, the C45 with WC-Cu coating, were investigated in the tribological laboratory. A metallic coating of the WC-Cu base was applied on theC45 steel substrate using electro-spark deposition coating technology. The experiment used three samples with different percentage ratios of chemical elements in the coating structure. The tribometer working on a “Ball on Plate” principle was an investigation of the friction factor of all samples duringthe experiment. Subsequently, the surface of the samples was modified structure WC-Cu with laser technology. The microhardness of modified and unmodified coatings according to the Vickers methodology was investigated in the next stage. At the end of the experimental investigation, a braking simulation was created in the programming environment of the Matlab® software, considering all driving resistances. The researchers also focused on the simulation of heat conduction during braking for some considered driving modes with braking on a level and with a 20% slope roadway. The simulation of heat flow was carried out in the Matlab® programming environment using the Fourier partial differential equation for non-stationary heat conduction.