Acta Mechanica Slovaca - Latest articles
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Effects of Welding Sequences on Residual Stresses in a Butt Joint of Austenitic Piping
Chouaib Zeghida, Abdelmoumene Guedri
Acta Mechanica Slovaca 2023, 27(3):28-40 | DOI: 10.21496/ams.2023.026 
This study aimed to investigate the effects of welding sequences on residual stresses and distortions of welded components, using computational thermomechanical model-based finite element analysis (FEA). Residual stresses, a common outcome of welding, can cause material distortions and reduce product quality. We used FEA to simulate transient temperature fields generated during welding and evaluated their impact on the amplitude and distribution of residual stresses, the size of fusion and heat-affected zones, material microstructures, properties and fracture toughness. The study focused on an austenitic pipe butt junction, a commonly welded component...
Machining of Austenitic Stainless Steels - the Influence of Various Factors on the Machining Result
Miroslav Čička, Renáta Turisová, Ferdinand Kóča, Hana Pačaiová
Acta Mechanica Slovaca 2023, 27(3):18-26 | DOI: 10.21496/ams.2023.022
In today's world, AISI stainless steel accounts for almost half of the world's production and consumption for industrial purposes. Stainless steel is the most popular alloy widely used in the production of parts due to its properties such as high strength, high corrosion resistance or high ductility, but they are hard materials to machine from the metallurgical aspect, such as low thermal conductivity, chip formation, cutting tool wear. The focus of the paper is on machining stainless steel - a review, where various machining problems are discussed by different researchers and their probable solution can provide help to reduce tool wear, increase corrosion...
Design and Control of a 3D Printed Robotic Arm
Tamás Bárány, László Rónai
Acta Mechanica Slovaca 2023, 27(3):12-17 | DOI: 10.21496/ams.2023.029
The paper is dealing with a 3D printed robotic arm, which is capable to use in the education. The RRR type, 4 degrees of freedom robot is designed in the Autodesk Fusion 360 software, the body of each joint is manufactured by the use of Fused Deposition Modelling technology. The system uses micro servo units as actuators, the control unit is an ATmega2560 microcontroller. Inverse kinematics problem of the arm is solved by geometric approach, joint angles to be determined serve the basis of the control. The workspace of the robot can be analysed via a special purpose Excel spreadsheet. The control program is developed under VS Code software. The system...
Prosthetic Thumb Design and Development by Additive Manufacturing
Bibiána Ondrejová, Branko Štefanovič, Monika Michalíková, Lucia Bednarčíková, Martin Juhás, Viktória Rajťuková, Jozef Živčák
Acta Mechanica Slovaca 2023, 27(3):6-11 | DOI: 10.21496/ams.2023.028
The proposed work deals with the production of a thumb prosthesis from ASA (Acrylonitrile-styrene-acrylic) material using FDM (Fused deposition modeling) additive manufacturing technology. The prosthesis serves as a substitute for the deformity of the hand (absence of the thumb including the metacarpal bone) and as a support point for grasping objects to restore the lost opposition function of the thumb. The shape of the thumb and the socket of the prosthesis are designed individually based on a 3D scan of the subject's healthy hand. The design of the prosthesis was developed according to the anatomically correct condition and the user's requirements....
Use of Waste Heat Using Heat Pipes
Kamil Sikora
Acta Mechanica Slovaca 2023, 27(2):54-59 | DOI: 10.21496/ams.2023.024
The use of flue gas waste heat has been one of the most discussed topics in the field of energy management for a long time now. This is not only an economic question of wasteful use of the obtained heat, but also the ecological consequences caused by the increased amount of emissions, since most of the heat energy mankind still obtains is by burning fossil fuels. There are studies that try to prove that excessive burning of carbon can disrupt the balance of the planet's system, and according to some studies, it is the emissions of carbon dioxide produced by industry that cause the greenhouse effect, and the resulting increase in the temperature of...
Static Compressive Stress Tests of the 3D Grid Model in the Solid Edge Program
Ján Kopec, Peter Trebuňa, Miriam Pekarčíková, Matúš Matiscsák
Acta Mechanica Slovaca 2023, 27(2):48-52 | DOI: 10.21496/ams.2023.020
The company turned to us with a request for 3D printing of the grid, which is part of the cooling device. 3D printing became an attractive option for the company because creating a model would require making a mold and the company was looking for a financially viable option for production. 3D printing is a cheap option from a financial point of view since it is not necessary to have a mold, it is enough to redraw the model in the 3D form in the Solid Edge program. Another advantage is the price of the material and its properties, which we describe in more detail in this article. The only problem was the printing, more precisely the dimensions of the...
Analysis of the Alternative Robotic Palletizing Processes in the Aspect of Electric Energy Consumption
Łukasz Sobaszek
Acta Mechanica Slovaca 2023, 27(2):42-47 | DOI: 10.21496/ams.2023.025
Modern implementations of industrial robots require the use of extensive knowledge and novel concepts. To bring real benefits, robotized processes must be analysed in detail. This paper presents a preliminary study on the analysis of electric energy consumption of an industrial robot in the alternative palletization processes. Firstly, the robotization of manufacturing processes aspect was discussed and advantages of the robotic palletizing process were presented. Secondly, the utilized off-line robot programming environment and a model of the robotic workstation used during the study were described. Conducting analyses based on the alternative arrangement...
Comparison of the Surface Roughness and its Geometric Model in Case of Z-level Milling
Balázs Mikó
Acta Mechanica Slovaca 2023, 27(2):32-41 | DOI: 10.21496/ams.2023.023
The Z-level milling technology is one of the most often used finishing milling strategy in case of the CNC milling of the steep free form surfaces. A main spindle parallel end-milling cutter can be used with or without corner radius, and the depth of cut means the axis parallel distance between the tool paths. During the planning of machining process two main aspects should be considered: the productivity and the accuracy. The accuracy means macro and micro accuracy. In this article the surface roughness, as a part of micro accuracy, is investigated, and a geometric approach of its estimation is presented. The tool corner geometry, the depth of cut...
Preparation and Basic Characterization of Novel Zinc-based Alloys for Intracorporeal Implants
Wanda Mamrilla, Zuzana Molčanová, Beáta Ballóková, Róbert Džunda, Karel Saksl
Acta Mechanica Slovaca 2023, 27(2):26-30 | DOI: 10.21496/ams.2023.018
Zinc is considered to be a suitable element for the preparation of bioresorbable materials that can gradually degrade in the human body without the production of toxic compounds and undesirable hydrogen gas. Zn is characterized by a much lower corrosion rate in saline compared to magnesium-zinc and its alloys. Therefore, in this work we investigate Zn-0.4Mg-0.4Ca-xMn alloys with 0, 0.2, 0.4, 0.6 0.8 and 1.1 wt. % Mn. The elements Mg, Ca and Mn were selected to improve the mechanical properties and biocompatibility of pure Zn. The microstructure of the alloys was studied by optical light microscope and SEM equipped with EDX analyzer. The mechanical...
Face Shield Frame Material Planning Using Quality Function Deployment
Kristína Lengyelová, Renáta Turisová
Acta Mechanica Slovaca 2023, 27(2):18-25 | DOI: 10.21496/ams.2023.007
The inspiration for the research was a customer request for 3D printing of face shield frames during the COVID-19 pandemic. In this context, but also due to the possibilities of relatively cheap 3D printing of various products, a large amount of waste started to be generated that needed to be disposed of. The overall aim of the research was to contribute to the development of new products printed using the 3D Fused Filament Fabrication (FFF) technology from thermoplastic materials, with a view to maximizing the quality level and minimizing the environmental footprint and cost of production. A modified Quality Function Development (QFD) methodology...
Hydraulic Regularities of Fluidized Bed During Encapsulation of Organo-mineral Fertilizers
Ruslan Ostroha, Mykola Yukhymenko, Oleksandr Mandryka
Acta Mechanica Slovaca 2023, 27(2):12-17 | DOI: 10.21496/ams.2023.015
The advantages of using encapsulated organo-mineral fertilizers are presented. It is proposed to use a fluidized bed apparatus for coating carbamide granules with an organic shell. Importance of the fluidized bed hydraulic characteristics and their influence on the energy costs of the process are emphasized. Experimental study results prove that irrigation density of granular layer with the suspension has significant influence on the hydraulic resistance of a fluidized bed. It is proposed an analytical dependence for determining the hydraulic resistance of a fluidized bed, which takes into account influence of the organic suspension flow rate.
Mathematical Model and Simulation of in-pipe Robot1. Introduction
Peter Ján Sinčák, Tomáš Merva, Ivan Virgala, Michal Kelemen
Acta Mechanica Slovaca 2023, 27(2):6-11 | DOI: 10.21496/ams.2022.018
At a time when most professions are undergoing massive automation and transformation there are still quite a few professions that have not changed in the past fifty years. One of those professions is chimney sweeping. This thought led to the initial idea for this paper. In this paper, we have proposed a design of an in-pipe robot that could be used for chimney cleaning and inspection. Mathematical modelling of the movement of the robot and actuators was carried out, which allowed us to study the proposed design. Since the mathematical model is quite abstract, computer simulations were done in order to prove the mathematical model, with the possibility...
Improving the Simulation of a Mobile Robot by imitations of Ultrasonic Sensors
Maksym Grytsiv, Marek Sukop, Martin Kočan, Dávid Kovaľuk, Dušan Mlinarček
Acta Mechanica Slovaca 2023, 27(1):66-70 | DOI: 10.21496/ams.2022.020
This article presents imitating the operation of an ultrasonic sensor in a 3D simulation of the Flowcode program to improve the performance and localization of a mobile robot. The main task will be to compare different methods of measuring distance using a simulation model of the sensor and determine the most profitable placement of these sensors to ensure trouble-free passage of obstacles without collisions.
Design of Printing Parameter Settings Methodology for FFF Printing of Waterproof Samples from a Flexible Material
Jiří Suder, Jakub Mlotek, Alan Panec, František Fojtík
Acta Mechanica Slovaca 2023, 27(1):58-64 | DOI: 10.21496/ams.2023.017
3D printing technology plays a key role in the design of prototypes and final parts. The ability to quickly and easily produce almost any shape using the Fused Filament Fabrication (FFF) method is used in almost every industrial sector, science and research. Materials for the FFF method can be divided into two groups, namely rigid and flexible. Flexible materials, in combination with pneumatics or hydraulics, offer a wide range of applications. However, in the FFF method, where individual fibers are stacked on each other and side by side, the question arises of whether the fibers will bond sufficiently to prevent water or air from passing through....
Effect of Tool Speed when Joining Dissimilar Materials by Flowdrill Technology
Nikita Veligotskyi, Erik Janoško, Anna Guzanová, Dagmar Draganovská
Acta Mechanica Slovaca 2023, 27(1):48-57 | DOI: 10.21496/ams.2023.011
This paper deals with the investigation of the effect of rotation speed on the form fit joint of dissimilar materials. Thin -walled materials based on steel and aluminium alloy were joined by thermal drilling. The shape and size of the resulting bushing were evaluated. It turned out that the best material combination for joining by flowdrill technology are joints made of steel and aluminum alloy. Aluminum alloy must always be placed in the bottom position. The best parameters of the formed bushing were achieved with the combination of DC-Al or TL-Al materials, at tool speeds of at least 2400 rpm.
Numerical Modelling of Flow in Fluidic Oscillator
Tomáš Blejchař, Sylva Drábková, Václav Janus
Acta Mechanica Slovaca 2023, 27(1):40-47 | DOI: 10.21496/ams.2023.019
The systems with fluidic oscillators are intensively studied nowadays because the oscillatory flow can increase heat and mass transfer and decrease energy dissipation. Fluidic oscillators produce an active-type mixing enhancement but in a passive manner as they do not require any moving parts. They convert steady pressurized inlet flow to oscillatory or pulsatile flow at an outlet without the need for external power. In general, there are many types of fluidic oscillators, categorized by the underlying mechanism to create oscillatory output behaviour. The fluidic oscillator with the single feedback loop is analysed in this paper. A numerical simulation...
PLC Effect at Different Types of Loading During Static Tensile Testing of Aluminium Alloys
Ivan Jandrlić, Tin Brlić, Lorena Mrkobrada, Milica Vučenović
Acta Mechanica Slovaca 2023, 27(1):34-38 | DOI: 10.21496/ams.2023.021
Aluminium and aluminium alloys are indispensable materials nowadays, widely used in various constructions. It is known that some aluminium alloys, such as Al-Mg, show inhomogeneous, localized deformation phenomena at certain temperatures and strain rates. This is known in the literature as the appearance of Portevin-Le Chatelier lines, or short the PLC-effect. The Portevin-Le Chatelier effect contributes to the reduction of material ductility and leaves surface defects on the final products. The study of this phenomenon was carried out using a static tensile test and the digital image correlation method. The influence of using a constant increase of...
Selection of Bridge Crane Beam Optimization Parameters
Jozef Kuľka, Marián Siman, Lucia Žuľová, Matúš Virostko, Matúš Kačír
Acta Mechanica Slovaca 2023, 27(1):26-33 | DOI: 10.21496/ams.2023.014
This paper is focused on the suitability of the selection of the parameters of the supporting structure of the bridge crane for the needs of cross-section optimization. The cross section of the beam is analysed in terms of its rigidity and dimensions with respect to the span of the crane. When optimizing to reduce overall weight, recommendations are given to address the issue of cross-sectional stability. An iterative procedure for the design of the cross-section of the beam at the specified load capacity of the crane and its span is proposed. In the article, only a theoretical analysis of the issue for the selection of suitable cross-section parameters...
Fast Three-phase Mass Minimization of Truss and Shell Structures with Stress and Stiffness Constraints
Ľubomír Ondris
Acta Mechanica Slovaca 2023, 27(1):16-25 | DOI: 10.21496/ams.2023.013
The paper describes a new iterative optimization procedure and its simple to use computer implementation, allowing to minimize the mass of truss and shell structures under static load while satisfying the stress and stiffness constraints and keeping the mesh topology of the structure. The procedure first fulfils the stress constraint, then the stiffness constraint. Finally, the continuously found design variables can be replaced by discrete values from user's catalogue. Seven optimized structures are described, and results are discussed in detail. Compared to other optimization procedures, the described technique is an order of magnitude faster and...
Experimental Study of the Impact of Notches Made in the Front Edge of Adherends on the Properties of Static and Fatigue Strength of Adhesive Joints
Andrzej Kubit, Władysław Zielecki, Wojciech Berezowski, Ryszard Perłowski, Katarzyna Łabno, Tomáš Katrňák
Acta Mechanica Slovaca 2023, 27(1):6-14 | DOI: 10.21496/ams.2023.010
This paper presents the effect of simple structural changes consisting in making notches on the edge of adherends on the static and fatigue properties of adhesive joints. The study is based on the set of experimental static strength tests of the single lap shear adhesive joints. It has been shown that a slight increase in load capacity is possible by using adhesive-filled notches. However, this structural modification leads to an increase in the standard deviation of test results. Based on the fatigue strength tests done at the limit number of cycles equal to 2×106, it was shown that the use of notches on the front edge of adherends, which...