Leon Kukiełka

Prof. Dr. Leon Kukiełka

Faculty of Mechanical Engineering, Technical University of Koszalin, Koszalin, Poland
orcid

Research Focus & Metrics

Academic Career Length

38Years (1989-Present)

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

Representative Publications

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16 July 2020 in Materials
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Lukasz BohdalLukasz Bohdal
Lukasz Bohdal
Leon KukiełkaLeon Kukiełka
Leon Kukiełka
Stanisław LegutkoStanisław Legutko
Stanisław Legutko
Radoslaw PatykRadoslaw Patyk
Radoslaw Patyk
Mykola RadchenkoMykola Radchenko
Mykola Radchenko
This work presents experimental studies with numerical modeling, aiming at the development of guidelines for shaping aluminum alloy AA6111-T4, t = 1.5 mm thick, with the use of a shear-slitting operation. During the experimental tests, parametric analyses were conducted for the selected material thickness. For the purposes of the material deformation’s analysis, a vision system based on the digital image correlation (DiC) method was used. Numerical models were developed with the use of finite element analysis (FEA) and the mesh-free method: smoothed particle hydrodynamics (SPH), which were used to analyze the residual stress and strain in the cutting zone at different process conditions. The results indicate a significant effect of the horizontal clearance between knives on the width of the deformation zone on sheet cut edge. Together with the clearance value increase, the deformation zone increases. The highest burrs on the cut edge were obtained, when the slitting speed was set to v = 17 m/min, and clearance to hc = 6%t. A strong influence was observed of the horizontal clearance value at high slitting speeds on burr unshapeliness. The most favorable conditions were obtained for v = 32 m/min, hc = 0.062 mm, and rake angle of upper knife for α = 30°. For this configuration, a smooth sheared edge with minimal burr height was obtained.



27 November 2021 in Materials
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Magdalena Zawada-MichałowskaMagdalena Zawada-Michałowska
Magdalena Zawada-Michałowska
Paweł PieśkoPaweł Pieśko
Paweł Pieśko
Jerzy JózwikJerzy Józwik
Jerzy Józwik
Stanisław LegutkoStanisław Legutko
Stanisław Legutko
Leon KukiełkaLeon Kukiełka
Leon Kukiełka
In modern constructions, especially aircraft, the aim is to minimize the weight of the components used. This necessitates the use of innovative construction materials, or the production of these parts with ever-decreasing wall thicknesses. To simplify assembly and improve strength properties, so-called structural elements are being used in the form of monolithic elements, which are replacing the assemblies of parts joined by, for example, riveting. These structures often have a complex, thin-walled geometry with deep pockets. This paper attempts to assess the accuracy of manufacturing thin-walled elements, in the shape of walls with different geometries, made of various aluminum alloys. Machining tests were conducted at different cutting speeds, which allowed comparisons of the geometric accuracy of parts manufactured under conventional and high-speed cutting conditions. Based on the result obtained, it was found that the elements made of EN AW-7075 T651 alloy underwent the greatest deformations during machining in comparison to other two materials (EN AW-6082 T651 and EN AC-43000). An increase in the geometrical accuracy of the manufactured elements was also observed with the increase in the cutting speed for the HSC range. Hence, to minimize the postmachining deformation of thin-walled elements, the use of high-speed cutting is justified.

6 October 2021 in Materials
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MKMarek Kowalik
Marek Kowalik
Tomasz TrzepiecińskiTomasz Trzepieciński
Tomasz Trzepieciński
Leon KukiełkaLeon Kukiełka
Leon Kukiełka
PPPiotr Paszta
Piotr Paszta
PMPaweł Maciąg
Paweł Maciąg
Stanisław LegutkoStanisław Legutko
Stanisław Legutko
The article presents the results of investigations into the depth of the plastically deformed surface layer in the roller burnishing process. The investigation was carried out in order to obtain information on the dependence relationship between the depth of plastic deformation, the pressure on the roller and the braking torque. The research was carried out according to the original method developed by the authors, in which the depth of plastic deformation is increased by applying a braking torque to the burnishing roller. In this method, it is possible to significantly increase (up to 20%) the depth of plastic deformation of the surface layer. The tests were carried out on a specially designed device on which the braking torque can be set and the force of the rolling resistance of the roller during burnishing can be measured. The tests were carried out on specimens made of C45 heat-treatable carbon steel. The dependence of the depth of the plastically deformed surface layer was determined for a given pressure force and variable braking moments. The depth of the plastically deformed layer was measured on the deformed end face of the ring-shaped samples. The microhardness in the sample cross-section and the evolution of the microstructure were both analysed.

9 January 2023 in Materials
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Grzegorz ChomkaGrzegorz Chomka
Grzegorz Chomka
Maciej Bartłomiej KasperowiczMaciej Bartłomiej Kasperowicz
Maciej Bartłomiej Kasperowicz
Jarosław ChodórJarosław Chodór
Jarosław Chodór
JCJerzy Chudy
Jerzy Chudy
Leon KukiełkaLeon Kukiełka
Leon Kukiełka
The paper concerns the application a high-pressure abrasive waterjet (AWJ) for cutting the most commonly used rock materials such as granite, limestone, basalt and marble. Based on the analysis of the literature, the influence of parameters on the specific energy Ev, specific energy of cutting Er and specific energy of intersection Ea was determined. Experimental studies were carried out on a laboratory test stand in accordance with a five-level rotating experiment plan. The results of the research were subjected to statistical processing, obtaining regression equations. The influence of the pressure and diameter of the abrasive waterjet on the energy consumption of rock cutting was tested. The effect of the stream power, feed speed and pressure on the cutting depth with the AWJ was also determined. The data obtained made it possible to evaluate the machinability of the rocks as a function of the power of the jet. These analyses were supplemented with charts illustrating the influence of the most important technological parameter of the cutting process, which is the feed speed. The presented results provide answers to the energy and time requirements for efficient cutting with the AWJ of frequently used rock materials.