Explore CTU's Digital Library

Access research publications, theses and academic works

Faculty of Civil Engineering Faculty of Mechanical Engineering Faculty of Electrical Engineering Faculty of Nuclear Sciences and Physical Engineering Faculty of Architecture Faculty of Transportation Sciences Faculty of Biomedical Engineering Faculty of Information Technology Klokner Institute Masaryk Institute of Advanced Studies Central Library Acta Polytechnica Acta Polytechnica CTU Proceedings CTU Publishing Activity

Recent Submissions

Design of a core drilling rig drive
(České vysoké učení technické v Praze, 2026) Dynybyl, Vojtěch; Starý, František; Bradáč, Josef; David, Jiří; Švec, Pavel
This paper deals with the design of drives for a geological core drilling rig. This rig is a special case since it requires an electric drive instead of a hydraulic one. In addition, the modularity of the rig with a maximal module weight limitation of 50 kg is another challenge.In the case of the drilling head drive, the problem lies in the use of two different drilling bit materials, depending on the material to be drilled and the chosen tool diameter. This leads to a need for variable speed and torque of the drive. The stroke drive must be capable of traversing rapidly at 3 m min−1 during tool extraction and, in extreme cases, operating at zero speed during drilling.The first option considered was an asynchronous electric motor. However, due to its high weight and inability to maintain torque at zero speed, it was rejected. The second option considered was an EV motor, with the main advantage being its low weight. However, this option was also rejected as the motor is not compatible with the drill gearbox and it would require a custom-made gearbox, which would make the drill assembly too expensive. The last option considered was a servomotor. Its advantages, including easy PLC control and operating parameters sensing, outweigh its higher price.
The implementation of reduced-order models in the development process of a rubber-metal component for an electric drive unit
(České vysoké učení technické v Praze, 2026) Danko, Ján; Dobrovolný, Juraj; Milesich, Tomáš; Kevický, Igor
This thesis focuses on streamlining the development process of rubber-metal elements (RMEs) for mountelectric drive units (EDUs) in electric vehicles using reduced-order models (ROMs) and deep learning techniques. Traditional methods for developing these RME are both time-consuming and costly. Therefore, the aim of this work was to design and implement a more efficient approach utilising modern deep learning techniques. An innovative methodology was developed, which combines ROM with deep learning, enabling the creation of accurate and fast predictive models for RME behaviour without the need for extensive finite element (FE) analyses. The ROMs were developed and subsequently implemented into an application for predicting the static and dynamic characteristics of RMEs. The results demonstrated that this methodology significantly reduced the development time and improved simulation accuracy compared to conventional approaches.
Design of a core drilling rig drive
(České vysoké učení technické v Praze, 2026) Dynybyl, Vojtěch; Starý, František; Bradáč, Josef; David, Jiří; Švec, Pavel
This paper deals with the design of drives for a geological core drilling rig. This rig is a special case since it requires an electric drive instead of a hydraulic one. In addition, the modularity of the rig with a maximal module weight limitation of 50 kg is another challenge.In the case of the drilling head drive, the problem lies in the use of two different drilling bit materials, depending on the material to be drilled and the chosen tool diameter. This leads to a need for variable speed and torque of the drive. The stroke drive must be capable of traversing rapidly at 3 m min−1 during tool extraction and, in extreme cases, operating at zero speed during drilling.The first option considered was an asynchronous electric motor. However, due to its high weight and inability to maintain torque at zero speed, it was rejected. The second option considered was an EV motor, with the main advantage being its low weight. However, this option was also rejected as the motor is not compatible with the drill gearbox and it would require a custom-made gearbox, which would make the drill assembly too expensive. The last option considered was a servomotor. Its advantages, including easy PLC control and operating parameters sensing, outweigh its higher price.
Experimental study on surface grinding of titanium alloys
(České vysoké učení technické v Praze, 2026) Festas, António; Sousa, Rui; Davim, João Paulo
Due to their unique characteristics, titanium alloys have found increasing application in a wide range of sectors, including aerospace, automotive, and biomedicine. The aim of developing new alloys is to enhance their properties and address emerging challenges. In this regard, Ti-6Al-7Nb and Ti-13Zr-13Nb alloys are potential replacements for the widely used Ti-6Al-4V alloys and its Ti-6Al-4V ELI variant.This study aimed to evaluate the difference in surface finish obtained through surface grinding of the aforementioned alloys. For this purpose, test-samples were subjected to grinding tests where the differentiating factors were the number of cutting passes, depth of cut, and use of lubrication. The results indicate that the lowest roughness values were obtained using a multi-pass deep cutting strategy and abundant cooling. According to the analysis that was carried out, the results indicate that the lowest roughness values were obtained for the Ti-13Zr-13Nb alloy in the longitudinal cutting direction (20–30 % lower than for the transverse direction), using a multi-pass deep cutting strategy (ap = 2 μm×10 times) with Ra = 0.29 μm and Rt = 2.73 μm and for abundant cooling with Ra = 0.55 μm and Rt = 4.81 μm (20 % lower than the dry condition).
Analysis of the properties of roller-compacted concrete with recycled aggregate pavement under high temperatures
(České vysoké učení technické v Praze, 2026) Ali Kouadri, Fadhila; Salhi, Mohamed; Boubekeur, Toufik; Benyahia, Amar; Li, Alex; Abbès, Boussad; Dahmane, Mouloud; Safer, Omar
In some countries, Reclaimed Asphalt Pavement (RAP) from old bituminous pavements is increasingly being recycled for economic and environmental reasons. In Algeria, large quantities of RAP are generated each year, yet they are seldom measured or repurposed. This study explores the potential of using coarse RAP as a substitute for coarse natural aggregates (NA) in roller-compacted concrete pavement (RCCP). Specimens with five levels of RAP replacement (0 %, 25 %, 50 %, 75 %, and 100 %) were prepared and tested. Fresh properties, such as fresh density (FD), Vebe consistency time, and air content, were evaluated. The influence of curing temperatures (20 °C, 40 °C, and 60 °C) on the properties of the hardened concrete was examined, focusing on compressive strength (CS), flexural strength (FS), modulus of elasticity (ME), ultrasonic pulse velocity (UPV), Cantabro abrasion (CA), Porosity (P), water absorption (WA), and sorptivity (S). The Vebe time for 100% RAP decreased by up to 61% compared to the reference mix. The CS was reduced by approximately 32.6 %, 46.2 %, and 60% for RAP substitution at 25 %, 50 %, and 100 %, respectively. The porosity decreased from 20 % to 48 % when RAP was added. The results show that RCCP can incorporate up to 50% RAP without a significant loss of performance. This offers an environmentally beneficial solution by reducing the amount of RAP that is discarded into the environment and the need for raw materials, thus conserving natural resources.