bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tightness of flange joints: A case study
Authors: Lošák P , Létal T , Naď M , Pernica M 
Published: April 2020

Abstract
One of the negative technological factors that often have a significant impact on the environment is the leakage of operating media (so-called fugitive emissions), which most often occurs at different separable joints. Therefore, high demands are placed on the joints – they must have sufficient strength to maintain pressure and other loads and also be tight enough to avoid undesired leaks. For a large part of such joints, standard flanges or flanges designed according to standards are used, in the European Union in particular according to EN 1092-1, EN 1591-1 and EN 13445-3. Although the strength of such flanges is sufficient for most applications, the basic design methods do not cover the tightness of flange joints and their emissions completely. A case inspired by industrial practice with a history of insufficient tightness resulting in leaks is investigated using FEA and EN 1591. The flange joint is modelled in software ANSYS 2019 R2 with parts of adjacent shells to take their effect into account. The goal of the analyses is estimation of gasket contact pressures resulting from load history. The pressures are directly related to the seal tightness. Lastly, effect of shell shape modification on the gasket pressures is also investigated and the results are compared with those from the original configuration. Effects of resulting pressures on seal tightness are discussed.
Computation of temperature field by cell method and comparing with commercial software
Authors: Pernica M , Létal T , Lošák P , Naď M 
Published: April 2020

Abstract
This paper deals with the temperature field of the shell and tube heat exchanger with segmental baffles. Two different types of shell and tube heat exchangers were analysed by a numerical model for thermal-hydraulic rating called the cell method. The cell method is a numerical computational model for calculating of temperature field of a shell and tube heat exchanger with segmental baffles. A huge benefit of the cell method is especially its simplicity. The computation of temperature field by the cell method is very fast and without the necessity of powerful hardware accessories. For analyses, two different types of shell and tube heat exchangers with segmental baffles were used. First, a co-current flow heat exchanger with a floating head and second a counter-current flow heat exchanger with a fixed tubesheet. Both analysed heat exchangers are horizontal, have one tube and one shell pass and segmental baffles. The results from cell method were compared with results from the commercial software for thermal-hydraulic rating HTRI, which is one of the most widely used commercial software for solving thermal-hydraulic rating of heat exchangers. The scope of this paper is to assess how exact the cell method is and if its results are useful for a mechanical design of shell and tube heat exchanger with segmental baffles.
Simulation of child passenger collision in the rail vehicle interior
Authors: Špirk S , Vychytil J 
Published: April 2020

Abstract
Passive safety of rail vehicles is described by two documents. These requirements for structural crashworthiness are covered by EN 15227 standard. The GMRT 2100 standard (currently mandatory in UK) summarizes the requirements for interior safety. The actual legislation deals only with an injury of an average adult male (50 percentile). An assessment of interior passive safety for the wider population (5 and 95 percentile) will be other logical steps (in the near future). This approach is well known from automotive industry. This study identifies the most dangerous factors for child passenger collisions in the interior of a rail vehicle. Virtual simulations, finite element method and multibody simulations are used for that. It is possible to overtake the current trends and to carry out a rail interior safety assessment for children due to the excellent scalability of the VIRTHUMAN model. The data of the vehicle design were obtained from the local producers. The vehicles which are used in this research were developed recently and they are generally used. The injury criteria are used for probability of injury evaluation. Some first recommendations for rail interior design safe for children are provided at the end of this paper.
The design issues of rolling bearing assemblies
Authors: Talaśka K , Wojtkowiak D , Fierek A 
Published: April 2020

Abstract
The design of rolling bearing assemblies, e.g.: shaft bearings, calls for specialized engineering knowledge. The problem requires synthetic knowledge of machine design and construction as well as knowledge of bearing manufacturer specifications. Mounting bearings on shafts and in housings requires to maintain correct dimensional deviation. The actual condition of the roller surface of the external shaft pin and the external housing has a material influence on the working efficiency and durability of the bearing. The development of examination tools to determine the stress condition of pin/housing as well as bearing rings after installation is of great importance, as well as determining shape faults of specific type and deviations of particular value. The paper presents numerical analyses which allow to determine the state of stress in the contact area of the assembly components: pin/housing-bearing rinds. The study was performed for selected shape faults, selected bearings and specific deviation values.
Numerical analysis of thermal phenomena during surface heat treatment of AlZn5.5MgCu aluminum alloy by GTA welding method
Authors: Winczek J , Iwaszko J , Matuszewski M 
Published: April 2020

Abstract
In work, the modelling of a three-dimensional temperature field during surface modification of AlZn5.5MgCu aluminum alloy using GTAW (Gas Tungsten Arc Welding) technology is presented. GTAW is widely used for making welded joints using additional material (filler material). In the analyzed process, no additional material was used, and the effect of heat treatment was obtained by directly applying the electric arc to the surface of the material. The calculations were performed using Finite Element Method. The Goldak’s double ellipsoidal heat source model has been used in modelling. The thermal-mechanical properties of the material were assumed to depend on the temperature. The Workbench, DesignModeler, Mechanical, Fluent and CFD-Post modules of the ANSYS program were used for numerical simulations. In the description of the geometry of element heat treated, cube type elements were used, with density of grid in the heat affected zone. The temperature distributions in cross-sections of heated element as well as welding thermal cycles at selected points were analyzed. The results of numerical simulations were verified experimentally. Comparison of calculated and obtained in the experiment the fusion lines showed satisfactory compatibility.
Numerical study of linearization techniques for Bouc-Wen hysteresis model considering random inputs
Authors: Sága M , Vaško M , Ságová Z , Handrik M , Kopas P , Jakubovičová L , Muravev V V , Muraveva O V 
Published: April 2020

Abstract
Our study focuses on the numerical solution of the stochastic vibration of elastic-plastic mechanical systems with Gaussian random excitations. It’s realized the short review about linearization techniques in stochastic dynamics mainly with application in area of elastic-plastic finite element modelling using BW (Bouc-Wen) differential mathematical model. The presented methods of statistical linearization, Hurtado-Barbat’s modification of statistical linearization, statistical quadratization and Monte Carlo approach are applied to numerical testing.
Synthesis and sensitivity analysis of the crank-rocker mechanism
Authors: Sapietová A , Štalmach O , Sapieta M 
Published: April 2020

Abstract
Based on the theoretical background, this paper presents a design of a crank-rocker mechanism, which is also known as extreme case of the four-bar linkage. This is very common mechanism used for stone crushing in the practice. Initial functional design is performed by the method of geometric synthesis in combination with analytical calculations. The most common problem associated with the synthesis of the crank-rocker mechanism is that of designing the linkage for a given oscillation angle and a given time ratio. To improve the efficiency of the device is performed the sensitivity analysis in the MSC.ADAMS with the goal to refine the designed geometric parameters.
Methods for measuring the position of the centre of gravity of an anthropotechnic human-wheelchair system in dynamic conditions
Authors: Wieczorek B , Kukla M , Warguła Ł 
Published: April 2020

Abstract
The article presents the methods for measuring the position of the centre of gravity of an anthropotechnic human-wheelchair system in dynamic conditions. The methods were verified by the pilot studies using a pushrim-propelled wheelchair. Data processing methods were used to fit the ellipses to measured datasets including 4.463 to 3.434 points, where the ellipses are defined by their centres M C.G., inclinations α and semi-axes a and b. The method involves defining each ellipse fit to the dataset with a likelihood of inclusion of new position points of the centre of gravity. The ellipses characterized by the highest likelihood were selected, which for the tested cases was between 29.7 % to 40.9 %, depending on the test.
The problem of fixing the axisymmetric elements on the example of pulley mounting on the shaft
Authors: Domek G , Kołodziej A , Dziubek I 
Published: April 2020

Abstract
The paper present the problem of permanent fixing of the axisymmetric elements relative position on the example of pulley mounting on the shaft. A method of permanent and quick fixing of pulleys on shafts has been sought for years. A number of detachable and inseparable joint solutions are available. The authors are looking for an inseparable solution allowing for quick assembly in serial production conditions. The quality of this connection is important for the geometry of the transmission gear, as it has a significant impact on the quality of the transmission gear operation and the belt life.
The influence of the limit stress value on the sublimation rate during the dry ice densification process
Authors: Górecki J , Fierek A , Talaśka K , Wałęsa K 
Published: April 2020

Abstract
The article presents the results of research on the influence of limit stress of the densification process on sublimation of dry ice during the forming process in piston technology. The research concerns the process of agglomeration of waste material in fragmented form, obtained as a result of the crystallization process of liquid carbon dioxide. The material is characterized by low temperature and sublimation under ambient conditions. During the research, the focus was on determining the influence of the limit value of densification stress on the value of the material efficiency factor of the process. In previous studies, it was observed that the weight of the product in the form of pellets is significantly smaller than the fragmented dry ice dispensed to the densification chamber. In order to improve the efficiency of the process, tests were carried out to determine the characteristics describing its change in function of the limit value of the densification stress.
Analysis of residual stresses on guide bar of chainsaw
Authors: Kostka J , Čarák P , Frankovský P , Adamuščin M 
Published: April 2020

Abstract
Problematics of residual stresses is known in engineering practice, but it is often forgotten. They are present in each component. Residual stresses can be introduced into the material not only during the manufacturing process, but also when the equipment is used. Every machine system a special approach to its application during operation. In case of non-compliance with its boundary conditions failure can comply damage of components, which may even lead to complete deterioration of the equipment. The aim of the paper is to point out how improper use of equipment affects residual stresses that can lead to its damage. The most used method for determining residual stresses was used – hole drilling method. The practical part deals with the specific application of the hole drilling method on the selected component – the chainsaw guide bar. The next part of the theses is followed by an evaluation of the results and proposal of solution that will contribute to more efficient use of the given structural element and its lifetime.
The impact of wheelchairs driving support systems on the rolling resistance coefficient
Authors: Warguła Ł , Kukla M , Wieczorek B 
Published: April 2020

Abstract
The 21stcentury is characterized by an increase in the obesity of society, including people with disabilities. The increase in the weight of people in wheelchairs requires them to have more power to drive these types of vehicles. Diseases and a varied level of disability or infirmity may lead to the inability to overcome the resistance of a vehicle driven by muscle power, such as a wheelchair. The solution to this problem are systems supporting the motion of this type of vehicles among which we can distinguish electric-manual hybrid drives that add energy to the drive system and systems that reduce the amount of force necessary for the movement of the cart lowering at the same time of its moving speed. Systems and mechanisms that have been developed for this purpose contain an increased number of cooperating elements than in a classic wheelchair, leading to an increase in rolling resistance. The article presents the methodology and test results of rolling resistance coefficients of wheelchairs with innovative systems supporting their propulsion showing that the tested auxiliary drives generate an increase in rolling resistance of vehicles for the disabled from 30 % to 75 %.
Comparison of experimental flexural test with FE analysis for specimen with different size and shape of internal structure created by 3D printing’s
Authors: Dorčiak F , Vaško M , Bárnik F , Majko J 
Published: April 2020

Abstract
The aim of the paper was to compare experimentally measured values and bending test simulations. Specimens was created by 3D printing. Material for specimens is composite Onyx. The samples were different in the internal structure. The inner structure has a different shape and size. Flexural test measured stress from the force required to bend a beam under three points loading conditions. Aim this paper was to find out the data, which will used to select choice size and shape of the inner structure dimensions for parts that will loads with flexing. By optimizing the size and shape of the inner structure to ensure the choice of the right structure for a given issue with regard to material consumption. The samples are sized according to ISO 178. The test was carried out according to ASTM D790 and next ISO 178. Test measured the force required to bend the specimen he test is stopped when the specimen reaches 5 % deflection or the specimen breaks before 5 %. If the sample can withstand the desired deflection, the test will continue by norm ISO 178 and the test is stopped when the specimen breaks. The same was simulated in Ansys workbench using the FEM calculation method. These data processed in tables and graphs and mutually compared with boundary values. The lower limit or value will be a hollow sample. The upper limit was a solid sample where the highest stiffness is expected.
Modeling selected mechanical properties of magnetorheological elastomers
Authors: Kukla M 
Published: April 2020

Abstract
Magnetorheological elastomers are an important group of non-classical engineering materials. The aim of the works carried out is to study the influence of magnetic field on a series of mechanical properties of composite materials in this group. Based on prior analyses, a limited usability of the viscoelastic material model was identified for the purpose of describing the stress-strain relationship in magnetorheological elastomers. Therefore, it has become necessary to propose changes to this rheological model. The present article includes theoretical considerations in relation to the mathematical derivation of functions allowing to account for the influence of strain amplitude on the progressive character of the mechanical hysteresis loops in the materials under discussion. It also provides a detailed analysis of the derived formulas together with a discussion, supplemented with the description of employed simplifying assumptions.
FE modeling of continuous fiber reinforced thermoplastic composite structures produced by additive manufacturing
Authors: Majko J , Sága M , Vaško M , Handrik M , Ságová Z 
Published: April 2020

Abstract
Additive manufacturing is process of joining material, bringing many benefits such as customization and low production cost. Markforged developed Continuous fiber fabrication technology, which allows to print continuous fiber reinforced thermoplastic (CFRTP) composites. Although printed CFRTP parts achieve mechanical properties better than another 3D printed counterparts, there is demand to gain suitable mechanical properties comparable with conventionally manufactured parts using improvements in printing parameters and fiber deposition. In this paper, the main goal is analyzing of geometry constraints of fiber deposition and modeling options in FEM program ADINA. Additionally, stress distribution analysis with regard to stresses in matrix and fibers will be performed.
Elastomer modification by means of ionizing radiation
Authors: Bobrova V , Kasperovich A , Mozyrev A , Krmela J , Krmelová V 
Published: April 2020

Abstract
One of the priorities for improving the performance characteristics of elastomer compositions is their physical modification, which allows to obtain materials with a new set of performance properties. Among the known methods of modifying products based on elastomers, one of the actual methods is radiation modification. It allows you to control the physico-mechanical and elastic-strength characteristics of products. In connection with the foregoing, the development of a technology for the radiation modification of elastomers with the aim of increasing their operational characteristics is relevant. In this work, the effect of ionizing radiation on the thermo-physical and operational properties of elastomeric compositions for the tread of career tires was investigated. It was established that the level of the maximum temperature developed in the samples depends on the degree of vulcanization of the elastomeric compositions. In samples of tread rubber, heat generation is reduced by 2–4 % after treatment with accelerated electrons. In the process of exposure to ionizing radiation, the formation of free radicals and their subsequent recombination occurs. Revealed an increase in crosslinking density in modified specimens. The correlation dependences between the thermophysical properties of elastomeric compositions and the intensity of heat generation in them are established. It was determined that the best thermo-physical properties of polymers with a degree of crosslinking t80. The wear resistance of the modified elastomeric compositions is increased up to 3.5 times.
Influence of mounting on hanging bolt lifetime
Authors: Dubec A , Kováčiková P , Janeková M 
Published: April 2020

Abstract
The main objective of this article is analysis of the hanging bolt failure that forms part of the weight transfer device. The base material of this bolt was protected by a surface layer to prevent corrosive influence of the environment. This bolt was used in combination with another screw of the same type to fix the movement of the device in the horizontal direction. This device operates by means of a hydraulic circuit at the rear of the agricultural machine and performs a vertical axis movement. The fracture surfaces of the bolt failure were evaluated on a thermo-emission scanning electron microscope. In the next part of the experiment, the micro-purity and microstructure of the material of the damaged hanging bolt was evaluated by optical microscopy. The main benefit of this article is the study of hanging bolt failure depending on the mounting design condition and from the way of its loading. Knowledge from this research is important to ensure safety with handling and protecting heavy loads from damage.
The impact of DCSBD plasma discharge on polypropylene
Authors: Janík R , Kohutiar M , Pajtášová M , Dubec A , Pagáčová J , Šulcová J 
Published: April 2020

Abstract
The diffuse coplanar surface barrier plasma discharge (DCSBD) still belongs to specific methods of modifying (activating) the surface of polymeric materials. The present work deals with surface treatment of polypropylene foils by plasma discharge, investigation and subsequent identification of changes caused by mentioned discharge. The modified surface was examined by measuring the wetting angle. Film surface morphology and topography was investigated by scanning electron microscope (SEM) and atomic force microscopy (AFM), respectively. Subsequently, it was examined whether the modification of polypropylene by DCSBD plasma discharge only affects the surface of the investigated material or also changes structural properties in studied material, based on the obtained data from DMA analysis.
The threaded part wear of the tensioner with lock nut
Authors: Kováčiková P , Dubec A , Koštialiková D 
Published: April 2020

Abstract
The tensioner with lock nut is an important part of the timing mechanism, which is often used in motorized engines. This component consists of a plurality of parts which are connected to each other by a threaded part. The threaded part of the tensioner serves to precisely adjust the position of its front part against the timing chain. This setting ensures the correct position of the guide part and thus the running of the motorcycle engine. The benefit of this research is the analysis of changes on the threaded part surface, which is important for correct working of the tensioner it is necessary that the threaded part fulfill its purpose. It is necessary to prevent its degradation or excessive wear. Scanning electron microscopy and energy dispersive spectroscopy methods were used to determine the wear of the threaded part of the tensioner. The evaluation focused on surface changes in the threaded part and the possible occurrence of foreign particles on the surface with respect to their material contrast and chemical composition.
Structure and properties of nucleated polypropylene fibres
Authors: Krmelová V , Gavendová M , Zatroch T , Krmela J , Dubec A , Bizubová B , Kleščík M , Balogová A 
Published: April 2020

Abstract
This work is focused on the evaluation of the structure and properties of the nucleated polypropylene (PP) fibres prepared by melt spinning technique at lower take-up velocities as pre-oriented fibres (POY) containing 0.3–1.5 wt. % of additives - nucleating agents like 1,3:2,4-dibenzylidene sorbitol (DBS), quinacridone (QA) and calcium carbonate (CC). The thermal properties of nucleated PP fibres were determined by using differential scanning calorimetry (DSC). Used additives promote nucleation activity, DBS and QA better than CC, as they increased the crystallization temperature to higher extent than CC. Effect of CC seems to be negligible, due to very little impact on melting point and crystallization temperature. Morphological characteristic of the PP fibres were observed by means of scanning electron microscopy. The morphology of nucleated PP is different significantly from that of reference non-nucleated PP fibre. The measured values of the above mentioned properties were compared with parameters of non-nucleated PP fibre prepared under same technological conditions.