Bogusław Łazarz

Prof. Dr. Bogusław Łazarz

Department of Road Transport, Faculty of Transport and Aviation Engineering, Silesian University of Technology, 40-019 Katowice, Poland
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Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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6 November 2020 in Energies
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Katarzyna TurońKatarzyna Turoń
Katarzyna Turoń
Andrzej KubikAndrzej Kubik
Andrzej Kubik
Feng ChenFeng Chen
Feng Chen
HWHualan Wang
Hualan Wang
Bogusław ŁazarzBogusław Łazarz
Bogusław Łazarz
Due to the development of the shared economy, increasingly more shared mobility providers have launched services based on the use of electric vehicles. The increasing growth of electric shared mobility services has produced various types of problems that do not occur (or occur with a limited effect) under conventional shared mobility systems. This increase in electric shared mobility problems has led to many effects, including limitations of the system zones or going out of business. To avoid difficulties in the functioning of electric shared mobility systems, various scientific studies have been undertaken to model and optimize the operation of these systems. Modeling and optimization mainly relate to one category of the system—for example, only to bike sharing. However, to understand the system of electric shared mobility holistically, there is a need to define the criteria generally as stimulants or destimulants. Based on these assumptions, we conducted research on the identification of factors influencing the development of electric shared mobility services. We conducted our own expert research based on the Social Network Analysis method. The aim of this study was to determine the factors that influence the development or recession of services in the entire electric shared mobility market in reference to selected stakeholders. The obtained results indicate a non-standard approach to the modeling and optimization of electric shared mobility services. This study could be used as support for creating electric shared mobility models and could also be helpful for service providers or local mobility managers through the developed recommendations.

15 March 2021 in Transport Problems
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KDKamil Duda
Kamil Duda
SWSławomir Wierzbicki
Sławomir Wierzbicki
MMMaciej Mikulski
Maciej Mikulski
ŁKŁukasz Konieczny
Łukasz Konieczny
Bogusław ŁazarzBogusław Łazarz
Bogusław Łazarz
MLMagdalena Letuń-Łątka
Magdalena Letuń-Łątka

5 February 2021 in Metals
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Tomasz Jan WęgrzynTomasz Jan Węgrzyn
Tomasz Jan Węgrzyn
TSTadeusz Szymczak
Tadeusz Szymczak
Bożena Szczucka-LasotaBożena Szczucka-Lasota
Bożena Szczucka-Lasota
Bogusław ŁazarzBogusław Łazarz
Bogusław Łazarz
Advanced high-strength steel (AHSS) steels are relatively not very well weldable because of the dominant martensitic structure with coarse ferrite and bainite. The utmost difficulty in welding these steels is their tendency to crack both in the heat affected zone (HAZ) and in weld. The significant disadvantage is that the strength of the welded joint is much lower in comparison to base material. Adopting the new technology regarding micro-jet cooling (MJC) after welding with micro-jet cooling could be the way to steer the microstructure of weld metal deposit. Welding with micro-jet cooling might be treated as a very promising welding S700MC steel process. Tensile and fatigue tests were mainly carried out as the main destructive experiments for examining the weld. Also bending probes, metallographic structure analysis, and some non-destructive measurements were performed. The welds were created using innovative technology by MAG welding with micro-jet cooling. The paper aims to verify the fatigue and tensile properties of the thin-walled S700MC steel structure after welding with various parameters of micro-cooling. For the first time, micro-jet cooling was used to weld S700MC steel in order to check the proper mechanical properties of the joint. The main results are processed in the form of the Wöhler’s S–N curves (alternating stress versus number cycles to failure).

1 January 2011 in Archive of Mechanical Engineering
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Tomasz FiglusTomasz Figlus
Tomasz Figlus
AWAndrzej Wilk
Andrzej Wilk
HMHenryk Madej
Henryk Madej
Bogusław ŁazarzBogusław Łazarz
Bogusław Łazarz
Investigation of Gearbox Vibroactivity with the Use of Vibration and Acoustic Pressure Start-Up Characteristics: This article presents the results of investigating the influence of tooth contact ratio in helical cylindrical gears on vibroactivity of the gearbox. Based on the measurements carried out on a laboratory test stand, time-domain and frequency-domain start-up characteristics of vibrations and acoustic pressure were determined, and vibroactivity was assessed for a gearbox in which 4 pairs of gears were successively mounted with different face contact ratios equal to, respectively, εβ=1,001; 1,318; 1,574; 2,636.

21 May 2021 in Materials
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TSTadeusz Szymczak
Tadeusz Szymczak
Bożena Szczucka-LasotaBożena Szczucka-Lasota
Bożena Szczucka-Lasota
Tomasz Jan WęgrzynTomasz Jan Węgrzyn
Tomasz Jan Węgrzyn
Bogusław ŁazarzBogusław Łazarz
Bogusław Łazarz
AJAdam Jurek
Adam Jurek
The paper is focused on testing the weld of the S960MC steel produced at the micro-jet cooling under static and fatigue loading at critical parameters. This kind of material was in the form of a sheet with a thickness equal to 2 mm. The joint was obtained using three different types of welding wires: EDFK 1000, Union NiMoCr and Union X96 at the same parameters of the process. The joints were examined using non-destructive and destructive tests. The results from non-destructive experiments enable us to assess the quality of the welds directly before the joining process. In contrast, the destructive one allows following welds behavior under different loading conditions with their critical parameters. The bending experiments confirmed the good plastic properties of the weld, expressed by no cracks in the region tested in many variants of the joint manufactured. The results from static tests indicated a significant reduction of mechanical parameters of the weld in comparison to the base metal, expressed by 50% differences. Fatigue data have enabled us to follow the welding behavior at the increasing amplitude of axial stress up to fracture at constant amplitude value covering the following values of stress 650 MPa–100 MPa. Variations of total energy are presented at different values of several cycles up to fracture. Fracture regions are collected for analysis of the joint region features under cyclic loading. They have indicated differences in weld cracking depended on the stress level. Finally, the Wöhler S-N curve of the weld was determined, indicating the value of the fatigue limit of the weld tested, i.e., 100 MPa. The weld at the Union NiMoCr welding wire was indicated as the joint having the highest resistance on static and fatigue loadings.

13 October 2022 in Materials
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Abilio P. SilvaAbilio P. Silva
Abilio P. Silva
Tomasz Jan WęgrzynTomasz Jan Węgrzyn
Tomasz Jan Węgrzyn
TSTadeusz Szymczak
Tadeusz Szymczak
Bożena Szczucka-LasotaBożena Szczucka-Lasota
Bożena Szczucka-Lasota
Bogusław ŁazarzBogusław Łazarz
Bogusław Łazarz
The demand for high-strength steel welds, as observed in civil and transport engineering, is related to a mass reduction in vehicles. Container-type trucks are examples of this kind of transport means because their boxes are able to be produced using Hardox grade steels. Therefore, this study reflects on the properties of welds in the MAG welding of Hardox 450, obtained through an innovative micro-jet cooling process with helium. This joining technology aims to reduce the formation of defects and to obtain a joint with very good assumed mechanical properties. Structural components of grade steel require welds with acceptable mechanical parameters with respect to operational loading conditions. That is, this study focuses on selecting welding parameters for the Hardox 450 steel and determining the weld quality with respect to microstructural observations and mechanical tests, such as the Charpy, tensile and fatigue tests. Weld fracturing under increasing monotonic force was examined and was strongly related to both stress components, i.e., axial and shear. The joint response under fatigue was expressed through differences in the fracture zones, i.e., at a stress value lower than the proportional limit, and weld degradation occurred in the shear and axial stress components. The data indicate that the hourglass specimen, with the weld in the centre zone of the measurement section, can be directly used to determine a weld response under cyclic loading. The impact test results showed attractive behaviour in the tested joint, as represented by 47 J at −20 °C. The recommended MAG welding parameters for Hardox 450 steel are low-oxygen when using an Ar + 18% CO2 shielding mixture. The collected results can be directly used as a guide to weld thin-walled structures (6 mm) made of Hardox grade steel, while the data from mechanical tests can support the modelling, designing and manufacturing of components made from this kind of steel grade.