No abstract

The article is focused on braking simulation of automated guided vehicle (AGV). The brake system is used with a disc brake and with hydraulic control. In the first step, the formula necessary for braking force at the start of braking is derived. The stopping distance is 1.5 meters. Subsequently, a mathematical model of braking is created into which the formula of the necessary braking force is applied. The mathematical model represents a motion equation that is solved in the software Matlab by an approximation method. Next a simulation is created using Matlab software and the data of simulation are displayed in the graph. The transport speed of the vehicle is 1 〖m.s〗^(-1) and the weight of the vehicle is 6000 kg including load. The aim of this article is to determine the braking time of the device depending from the input data entered, which represent the initial conditions of the braking process.

Research results of influence of the UIT (Ultrasonic Impact Treatment) on welded joints, executed on the Strenx 700MC steel, are presented in this paper. The fatigue tests of those joints were performed by rotating bending in the region of the high number of loading cycles (10 5 to 10 7) with parameters: frequency 35 Hz, cycles asymmetry factor-1, at the ambient temperature 20 ± 2 °C. The fatigue safety coefficient was calculated before the UIT (in the original state) and after the UIT, according to four methods. An increase was recorded for the latter state: for the Goodman method of 10.45 %, for the Gerber method of 10.21 %, for the ASME method of 5.96 % and for the Soderberg method of 7.40%.

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.

The authors of this manuscript present development of a prototype protective UV-C half-face mask. The first stage of this study focuses on proposing a UV-C half-face mask design and the second phase investigates the quality of printings, 3D/2D roughness and porousness of three different printed samples of PA12. Development of the protective half-face mask used the non-destructive technology of 3D scanning of the human body by the Ein Scan scanner. As a part of the experiment, three samples were prepared with Sinterit Lisa, EOS Formiga and HP jet fusion printers. SLS and MJF technology were used during the experiment. The experimental observation of the structure of the surface was secured using the Alicona Infinite focus G5 device. The conclusions present the study's results and the authors' recommendations for other developers dealing with the development of the protective face masks.

The authors of this manuscript present the development of a braking system with friction material base WC-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 the C45 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 during the 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.

The article is focused on optimizing the friction disc plates of the braking system integrated into the drive wheel of an automated guided vehicle. The introduction is focused on the application of these types of braking systems. In the next step, the individual mathematical parameters and the acting forces in the braking system are expressed. Using the equation of motion that is written in Matlab, the braking distance and the stop time are graphically expressed. During the Matlab simulation, different diameters of the braking plates are monitored to determine the braking distance. The permitted pressure in the braking plates during the test must not exceed the specified pressure of 2 MPa. The functionality of the braking plates is ensured by hydraulic power. Part of the wheel is a sensor that monitors the speed during braking. Ultimately, a continuous reduction in kinetic energy is achieved without vigorous blocking of the slats during braking. The acquisition of the paper is the output of numerical calculations, which are necessary for the correct design of the wheel with the integrated braking system.

In this paper the authors introduce results from the field of the fatigue safety of selected steels in the region of ultra - high number of loading cycles. The fatigue tests were carried out at high frequency tension - compression loading (f = 20 kHz, T = 20 ± 5°, R = -1) in the region from N = 106 to N = 109 cycles. The fatigue safety coefficients were calculated by four methods (Goodman, Gerber, ASME elliptic and Soderberg). The percentage reduction of the fatigue safety coefficients (N = 109 vs. N = 106 cycles) was at Goodman, 7.99 ÷ 10.83 %, Gerber, 5.27 ÷ 8.26 %, ASME, 1.89 ÷ 6.42 % and Soderberg, 6.51 ÷ 10.25 %.