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1

Practical application of the percolation phenomenon in spatial structures

Saraczyn Robert, Deroszewska Martyna, Miłek Tomasz

Polish Technical Review

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2024

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No. 3

2--6

EN

This study aimed to present the possibilities for the practical use of the percolation phenomenon. The percolation phenomenon and the related concepts were broadly described. 3D CAD models of spatial structures, 3D prints using L-PBF technology from AISI 316 austenitic steel, models of the hip joint endoprosthesis stem and microscopic photos of the prints were presented. A number of possibilities related to the practical use of percolation theory have been identified, but also several limitations that require in-depth scientific analysis. The main challenge is to create a methodology for determining the percolation threshold and a methodology for analysing the microstructure of polycrystalline materials in 3D.

PL

Celem pracy było przedstawienie możliwości praktycznego wykorzystania zjawiska perkolacji. Dokonano szerokiego opisu zjawiska perkolacji i pojęć z nim związanych. Zaprezentowano modele 3D CAD struktur przestrzennych, wydruki 3D w technologii L-PBF ze stali austenitycznej AISI 316, modele trzpienia endoprotezy stawu biodrowego oraz zdjęcia mikroskopowe wydruków. Zidentyfikowano szereg możliwości związanych z praktycznym zastosowaniem teorii perkolacji, ale także kilka ograniczeń wymagających pogłębionej analizy naukowej. Głównym wyzwaniem jest stworzenie metodologii wyznaczania progu perkolacji oraz metodologii analizy mikrostruktury materiałów polikrystalicznych w 3D.

2

The Influence of Selected Technological Parameters on Changes in the Flanging Load

Miłek Tomasz

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 6

266--279

EN

The flanging process is widely used in stamping production: when collar drawing small holes for threads or to increase the stiffness of a draw piece. It can also replace the operation of deep drawing cylindrical draw pieces with a large flange followed by cutting the bottom. The paper discusses the influence of the shape of the punch and the grade of material on load changes at various collar drawing coefficients. Flat, spherical and conical punches and samples made of EN-AW 1050A aluminium, Cu-ETP copper, CuZn37 brass, S235JRG2 steel, X6Cr17 steel and X5CrNi18-10 steel were used for testing. The relative thickness of test pieces was 0.015 (which corresponded to a thickness of 1 mm and a blank diameter of 66 mm). Various collar drawing factors ranging from 0.32 to 0.54 were adopted in the studies. An analysis of the obtained height of collars and wall thicknesses was carried out. The experimental tests were carried out using special tooling mounted on a testing machine with a 20kN load for 0.5 metrological class. Changes in the force as a function of the displacement of the punches were recorded using Test&Motion software that is commonly applied in research laboratories. Based on the obtained results at various technological parameters, possibility of flanging process was evaluated in industrial conditions

3

Identification of phase percolation in bainitic structures

Deroszewska Martyna, Saraczyn Robert, Miłek Tomasz, Troska Jakub

Polish Technical Review

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2023

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No. 2

23--28

EN

The aim of this study was to identify and study the phenomenon of phase percolation in bainite structures. SEM microscopic tests were carried out on bainitized iron alloy samples, in the FEM tests austenitic SS316 steel was used as the filled phase. Physical models, which were produced in the form of cubes and tensile samples, were made in FDM technology on the Original Prusa Mini+ printer from ASA filament (modified ABS copolymer). The static tensile test was performed on a LabTest 5.20 SP1 testing machine at a tensile speed of 10mm/min. Complex states of stress in the analyzed systems were identified, which prove the complexity of the phenomenon in multiphase materials. The obtained results were correlated, which allowed to indicate that the phenomenon of percolation indeed affects the mechanical properties of multiphase materials and incremental techniques can be used to analyze the level of this impact.

PL

Celem pracy było rozpoznanie i zbadanie zjawiska perkolacji fazowej w strukturach bainitu. Badania mikroskopowe SEM przeprowadzono na bainityzowanych próbkach stopu żelaza, w badaniach MES jako fazę wypełnioną zastosowano stal austenityczną SS316. Modele fizyczne, które wykonano w postaci kostek i próbek rozciągliwych, wykonano w technologii FDM na drukarce Original Prusa Mini+ z filamentu ASA (modyfikowany kopolimer ABS). Statyczną próbę rozciągania przeprowadzono na maszynie wytrzymałościowej LabTest 5.20 SP1 przy prędkości rozciągania 10 mm/min. Zidentyfikowano złożone stany naprężeń w analizowanych układach, które świadczą o złożoności zjawiska w materiałach wielofazowych. Uzyskane wyniki skorelowano, co pozwoliło wskazać, że zjawisko perkolacji rzeczywiście wpływa na właściwości mechaniczne materiałów wielofazowych, a techniki przyrostowe mogą być wykorzystane do analizy poziomu tego oddziaływania.

4

Experimental Determination of Material Boundary Conditions for Computer Simulation of Sheet Metal Deep Drawing Processes

Miłek Tomasz

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 5

360--373

EN

In solving technological problems related to sheet metal deep drawing with the use of computer tools, the key issue is still the correct determination and entering of boundary conditions to FEM-based software. The procedure for preparing input data for modelling such processes includes geometric data (drawing of tools and material), technological parameters along with the contact conditions between the workpiece and the tools (friction model and type of lubricant) and material properties, in which work-hardening curves are of particular importance. In typical material databases of FEM-based software and designed for computer modelling of deep drawing processes, the properties of only a small number of material grades are available, and commercial software producers charge additional fees for each additional quantity. Those properties that are already in the database are usually devoid of basic information, e.g. related to the state of the material (material after recrystallization, annealing, cold working has different properties). In paper, experimental tests were carried out to determine flow curves based on cold tensile curves for flat samples made of EN-AW 1050A aluminium, Cu-ETP copper, CuZn37 brass and S235JRG2 steel. The investigation used a universal testing machine with a 20kN pressing force, equipped with specialized TestMotion software for measuring forces and displacements. It was calibrated and satisfies the metrological requirements for class 0.5. A comparative analysis of the curves determined by the analytical method was carried out. The material models obtained in the experimental tests were used in the computer simulation of the deep drawing processes of cylindrical drawpieces in the ABAQUS software. The results were experimentally verified in terms of comparing the changes in the pressing forces as a function of the displacement of the punch. The results obtained in the research can be used in industrial practice for computer-aided design of cold-deep drawing processes for drawpieces of various shapes from the discussed materials.