Wyniki wyszukiwania - Biblioteka Nauki

1

Experimental and numerical investigations and optimisation of grain-oriented silicon steel mechanical cutting process

100%

Patyk R. , Bohdal Ł. , Gontarz S.

Acta Mechanica et Automatica

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2022

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tom Vol. 16, no. 3

292--300

EN

The process of mechanical cutting of magnetic materials has many advantages in the form of high efficiency with reduced process costs in relation to other cutting technologies; no thermal stresses in the material, which significantly deteriorate the magnetic properties; or the possibility of shaping materials taking into account long cutting lines. In industrial practice, it is very difficult to ensure appropriate conditions for the cutting process and its proper control. Currently, there are no data on the selection of technological parameters of the mechanical shear slitting process of grain-oriented silicon steel in terms of the obtained cutting surface quality and the obtained magnetic properties of the workpiece. The article presents the possibilities of forecasting the characteristic features of the cut edge and selected magnetic properties of grain-oriented silicon steel. For this purpose, proprietary numerical models using FEA (Finite Element Analysis) were used. Then, experimental studies were carried out, and the optimisation task was developed. The developed results enable the correct selection of technological parameters of the process, ensuring the appropriate quality of the cut edge of steel and minimal interference with the magnetic properties.

2

Modeling and numerical analysis of the process of punching aluminum sheets taking into account punch wear

88%

Bohdal Ł. , Kośka K. , Miksza M. , Patyk R. , Kalata F.

Journal of Mechanical and Energy Engineering

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2022

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tom Vol. 6, No 1

13--20

EN

The paper presents a modeling and analysis algorithm as well as the results of simulation tests with the use of FEM of a process of punching aluminum sheets used for casings. In industrial practice, the difficulty lies in the correct selection of punching clearance. In order to predict the effect of clearance on the quality of the edge cut, a numerical model was developed taking into account the geometric and physical nonlinearity with damage. The model makes it possible to simulate all the phases of the cutting process, including the fracture phase, which is of key importance to the formation of the workpiece edge. A new approach of creating a real geometry of the punch edge was presented. The geometries developed take into account the most common defects of the punch cut edges. Owing to this, it is possible to predict the course of the proces depending on the type and degree of the wear of the cutting edges of the punch. The results obtained showed that for clearances below the value of a = 0.16 mm, the crack has the shape of a straight line. Clearance values a = 0.16 mm and below allow one to obtain a perpendicular shear area and a considerable width of the smooth cutting zone. As the clearance increases, the width of the cutting zone decreases. Punch wear significantly reduces the smooth zone and it increases perpendicular deviation of cut surface.

3

Problem with determining the vehicle impact velocity for car bodies breaking apart

88%

Aleksandrowicz P. , Aleksandrowicz I. , Kukiełka K. , Patyk R. , Stanowski P.

Transport Problems

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2022

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tom T. 17, z. 3

75--86

EN

This article investigates the impact of a passenger car on a tree, which resulted in the car body breaking apart. A side impact of the car on a tree at high driving speeds is not a standard test in the provisions of the applicable Directives of the European Economic Community, even though the impact poses a serious threat to the driver and the passengers. The threat comes from a deep impaction of the barrier into the body which damages the safety cage. For such impacts, it is very difficult for the vehicle speed to be reconstructed. In practice, expert witnesses and appraisers usually disregard the bodybreaking-apart-related energy due to a difficulty in establishing the data for such calculations, which leads to simplifications and speed underestimates. Performing the right simulation of such impacts with accident reconstruction programs without determining the adequate input data for calculations is also impossible to calculate. This paper presents a range of studies and calculations for such incidents and for identifying the input parameters for collision simulations. The approach presented in this article should be used by expert witnesses and researchers. Therefore, this paper provides insights into theory and practice.

4

Investigations of polypropylene foil cutting process using fiber Nb: YAG and Diode Nd:YVO4 lasers

75%

Kukiełka L. , Patyk R. , Bohdal Ł. , Napadłek W. , Gryglicki R. , Kasprzak P.

Acta Mechanica et Automatica

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2019

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tom Vol. 13, no. 2

107--112

EN

Lasers are widely used in a variety of manufacturing processes including: depaneling, drilling, cutting, repair, trimming, micromachining. Polypropylene foils are intensively investigated as materials with great number of potential applications. Laser cutting is a major operation used in forming these materials and preparing the final workpieces. At the moment, the main challenge when cutting polypropylene is to obtain high quality products characterized by optimum sheared edge condition, minimum surface damage, freedom from burrs, slivers, edge wave, distortion, residual stresses and to obtain minimum width of HAZ zone. The amount of adjusTab. process parameters and the fact that the influence of these parameters on the process is not fully understood makes it difficult to control the cutting process. In practice, the right setup for the lasers is mostly found by trial and error combined with experience. Therefore, the final product frequently has serious defects. The paper presents the possibility of using fiber and diode lasers for forming of workpieces from polypropylene multilayer foil using cutting technology. The effect of selected process parameters and conditions on quality of sheared edge and material degradation is discussed.

5

Badania symulacyjne i eksperymentalne procesu wykrawania części z blach aluminiowych o zmiennej grubości

75%

Bohdal Ł. , Kalata F. , Kałduński P. , Kukiełka L. , Patyk R. , Kukiełka K.

Autobusy : technika, eksploatacja, systemy transportowe

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2019

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tom R. 20, nr 9

52--56

PL

W artykule przedstawiono algorytm modelowania i analizy oraz wyniki badań symulacyjnych z zastosowaniem MES oraz eksperymentalnych procesu wykrawania części z blach aluminiowych stosowanych w przemyśle motoryzacyjnym do budowy pojazdów. Uzyskuje się zarówno oszczędność energii oraz obniżenie masy samochodów. Analiza dotyczy wpływu warunków procesu wykrawania na jakość ciętej krawędzi wyrobu. Symulacje komputerowe przeprowadzono dla przestrzennych stanów naprężeń i płaskich stanów odkształceń z wykorzystaniem Solvera LS-DYNA oraz aplikacji LS-PrePost. Otrzymano mapy intensywności naprężeń i odkształceń dla dowolnej chwili czasowej z uwzględnieniem nieliniowości występujących w procesie wykrawania. Badania symulacyjne przeprowadzono dla różnych grubości blach oraz zmiennych wartości luzu miedzy stemplem a matrycą. Wyniki symulacji zweryfikowano eksperymentalnie. Opracowane aplikacje numeryczne oraz otrzymane wyniki badań mogą być wykorzystane do projektowania i optymalizacji procesu wykrawania.

EN

The paper presents the modeling and experimental researches of the blanking process of parts from aluminum sheets used in automotive industry to building vehicles. Analysis concerns influence of process conditions on quality of cut edge. Numerical analysis was performed for the spatial states of stresses and flat states of strains in LS-DYNA solver and LS-PrePost application regarding blanking process nonlinearities. Researches were realized for different sheet’s thickness and punch-die clearances. Results were verified experimentally. Obtained maps of stresses, strains, displacement at any moment of time can be used for design of the blanking process and it’s optimization.