Wyniki wyszukiwania - Biblioteka Nauki

1

The Complex Computer System Based on Cellular Automata Method Designed to Support Modelling of Laminar Cooling Processes

100%

Gołąb R. , Madej Ł. , Pietrzyk M.

|

tom Vol. 14, No. 1

63--73

EN

The user friendly computer system that have the capability of modelling material behaviour both at the macro and micro scales was developed in this work. The system was designed to predict microstructure evolution during phase transformation in laminar cooling conditions with the use of the multi scale cellular automata finite element (CAFE) model. The finite element (FE) part is based on the conventional Fourier type equation and is used to predict macroscopic temperature distribution. This is an input for the micro scale cellular automata (CA) model of austenite-ferrite phase transformation. To facilitate the research, proposed micro scale CA model was implemented within developed universal object-oriented programming framework CAF. Description of major assumptions and functionality of the developed numerical system including efficient Graphical User Interface (GUI) is presented in the paper. The intuitive visualization of data obtained in different length scales facilitates work with the software.

2

Numerical model of heat treatment using the generalized fdm. Part II

100%

Pawlak E. , Mendakiewicz J.

|

tom z. 59

19-22

EN

In the paper the example of numerical simulation of heat transfer proceeding during the cooling process in domain of infinite plate is presented. The model is constructed on the basis of generalized finite differences method - GFDM [1 , 2]. On the outer surfaces of the plate the Robin conditions are assumed, at the same time the heat transfer coefficient is the sum of radial and convective components.

3

Numerical model of heat treatment using the generalized fdm. Part I

100%

Majchrzak E. , Mochnacki B. , Pawlak E.

|

tom z. 59

15-18

EN

In the paper the numerical model of heat transfer proceeding during the heating and cooling processes in domain of solid is presented. The model is constructed on the basis of generalized finite differences method - GFDM [1, 2]. In order to simplify the considerations, a 1D task is discussed (the infinite plate). More complex (from the geometrical point of view) problems are in details described in [2].

4

Numerical modelling of cooling process using fuzzy boundary element method with alpha-cuts

75%

Piasecka-Belkhayat A.

Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej

|

2011

|

tom Vol. 10, nr 1

199-204

EN

In the paper, the description of an unsteady heat transfer for a two-dimensional problem is presented. It is assumed that all the thermophysical parameters appearing in the mathematical model of the problem analyzed are given as fuzzy numbers. The problem discussed has been solved by means of the 1st scheme of the fuzzy boundary element method using α-cuts. The application of α-cuts allows one to avoid complicated arithmetical operations in the fuzzy numbers set. The interval Gauss elimination method with the decomposition procedure has been applied to solve the obtained fuzzy system of equations. In the final part of the paper, the results of numerical computations are shown.

5

Metoda elementów brzegowych w modelowaniu stygnięcia odlewów o geometrii walcowej

75%

Szopa R.

|

tom nr 38

31--36

PL

W pracy przedstawiono możliwość wykorzystania tzw. kombinowanej metody elementów brzegowych do obliczeń procesu stygnięcia odlewu o geometrii walcowej. Wykorzystano algorytm dla zadania płaskiego i równania energii ze składnikiem źródłowym. Rozważano procesy bez przemian fazowych (np. obróbka cieplna). Uzupełnienie prezentowanego algorytmu dodatkowymi procedurami uwzględniającymi proces krzepnięcia pozwala również na jego wykorzystanie do analizy bardziej złożonych procesów cieplnych.

EN

The problem of application of the BEM using discretization in time in numerical computations of cooling processes proceeding in domain of cylindrical casting is discussed. The energy equation for 2D problem with additional component called the artificial source function is considered. In the paper only the cooling processes (e.g. the heat treatment) are analyzad, but the supplement of algorithm proposed by the procedures simulating the solidification process allows to solve more complex problems, too.

6

The graphic presentation of building's passive heating and cooling strategy

63%

Biedrońska J. , Figaszewski J.

Architecture Civil Engineering Environment

|

2015

|

tom Vol. 8, no. 1

5--11

EN

The proposed energy diagrams reveal a clear link between development of the spatial design and energy management in buildings. This relationship has an impact on the energy efficiency and microclimate of a given building. The mentioned relationship highlights an importance of incorporating the energy diagrams at the first step of the building design process since they have a very practical value. Showing a graphic representation of the heating and cooling processes can be an advantageous tool in energy efficiency analysis and finally the basis for adopting the optimum spatial as well as the construction and material solutions.

PL

Między kształtowaniem przestrzennym a gospodarowaniem energią w budynku istnieje wyraźny związek, który przekłada się na sprawność energetyczną i mikroklimat wnętrza budynku. Zależność ta uzasadnia potrzebę stosowania schematów energetycznych już na wstępnym etapie projektowania obiektu. Mają one wartość praktyczną. Przedstawiając w graficzny sposób procesy zachodzące w ramach strategii ogrzewania i chłodzenia, mogą być one pomocnym narzędziem analiz efektywności energetycznej i, w końcowym rozrachunku, podstawą przyjęcia optymalnych rozwiązań przestrzennych i konstrukcyjno-materiałowych.

7

Modelowanie przemian fazowych w stygnących odlewach staliwnych

63%

Parkitny R. , Winczek J.

|

tom nr 38

37--42

EN

In the paper the quantitative description of phase changes in flat wall of the casting is presented. TTTc -diagram for steel with chemical composition equivalent for cast steel 50L has been selected. Cooling rate of casting has been obtained by surface film conductance [....] depending on kind of cooling medium. Dilatometric curves, phase change diagrams and distribution of hardness for examples of cooling in casting mould and water have been show.

8

Influence of the Mould Cooling Process on the Quality and Properties of Aluminium Alloy

63%

Weiss V. , Svobodova J.

Production Engineering Archives

|

2014

|

tom Vol. 5, No. 4

36--41

EN

The article deals with the effect on the quality of casting moulds (metal, bentonite mixture) on the structure of the alloy AlZn5,5MgCu and selected mechanical properties of the alloy. The effect of foundry moulds can significantly affect formation and range of crystal segregation and the subsequent thermal process of homogenization which has an influence on the final quality of the alloy. The research focuses on the formation and range of crystal segregation and its removal with homogenization annealing, in which the observed influence of individual factors influencing the diffusion process and quality of the aluminium alloy.

9

Modelling of forced convection using a stabilized meshless method

63%

Kulawik A.

|

tom Vol. 9, nr 2

123-130

EN

Modeling of coolant flow is increasingly important in the problems of heat treatment. Variation of the coolant characteristics is not possible to present, as a boundary condition at the appropriate level of detail. This paper presents a solution of the heat transfer equation with a convective term and a Navier-Stokes equation for forced flow, which is characteristic for a hardening process. These equations are solved by means of a meshless method. The emerging models for solving thermal processes in coolants require a stable numerical method. In this paper a stabilization of the numerical models for the generalized finite difference method for both temperature and fluid flow models are proposed. The results obtained with software implementations of the proposed models are compared with the an analytical solution and with the numerical benchmarks.

10

Opracowanie i weryfikacja numeryczne go modelu chłodzenia pierścieni stosowanych w przemyśle lotniczym

63%

Perzyński K. , Madej Ł. , Pietrzyk M. , Szajding A. , Raga K. , Kubiak K.

|

tom R. 61, nr 5

209--212

PL

Celem niniejszej pracy jest opracowanie modelu numerycznego procesu hartowania wyrobów ze stali z uwzględnieniem wpływu przemian fazowych z wykorzystaniem komercyjnego oprogramowania numerycznego ANSYS. W artykule zaproponowano model numeryczny swobodnego chłodzenia pierścieni stalowych z uwzględnieniem zaimplementowanego modelu przemiany bainitycznej oraz martenzytycznej. Kluczowa w proponowanym rozwiązaniu jest możliwość rozpatrywania niejednorodności w polu temperatury wynikająca z różnych prędkości chłodzenia na przekroju poprzecznym pierścienia, co w rezultacie wpływa na dokładność przewidywania naprężeń szczątkowych. Weryfikacja opracowanego modelu z wykorzystaniem wyników badań laboratoryjnych potwierdza jego duże możliwości określania zmian zachodzących podczas procesu chłodzenia pierścieni.

EN

The main goal of the paper is development of the numerical model for cooling simulations of steel products taking into account phase transformations. The phase transformation model was incorporated via the user subroutines to the commercial finite element software. The cooling process of steel rings used in the aircraft industry was selected as a case study. Particular attention was put on heterogeneities occurring in temperature field, which will influence phase transformations and eventually residual stresses. Developed model was validated with experimental results and its good predictive capabilities have been proved.

11

Wykorzystanie efektu cieplnego przemiany fazowej woda-para w technikach chłodzenia

63%

Pluta Z.

|

2011

|

tom z. 27

225--232

12

Application of evolutionary algorithms to optimize the model parameters of casting cooling process

63%

Kluska-Nawarecka S. , Górny Z. , Smolarek-Grzyb A.

|

tom Vol. 10, iss. 4

89--92

EN

One of the most commonly used methods of numerical simulation is the finite element method (FEM). Its popularity is reflected in the number of tools supporting the preparation of simulation models. However, despite its usefulness, FEM is often very troublesome in use; the problem is the selection of the finite element mesh or shape function. In addition, MES assumes a complete knowledge of the simulated process and of the parameters describing the investigated phenomena, including model geometry, boundary conditions, physical parameters, and mathematical model describing these phenomena. A comparison of the data obtained from physical experiments and simulations indicates an inaccuracy, which may result from the incorrectly chosen shape of element or geometry of the grid. The application of computational intelligence methods, combined with knowledge of the manufacturing technology of metal products, should allow an efficient selection of parameters of the mathematical models and, as a consequence, more precise control of the process of the casting solidification and cooling to ensure the required quality. The designed system has been integrated with the existing simulation environment, which will significantly facilitate the preparation and implementation of calculations of this type. Moreover, the use of a distributed model will significantly reduce the time complexity of calculations, requiring multiple repetition of complex simulations to estimate the quality of the different sets of parameters.

13

Zastosowanie sztucznej sieci neuronowej do wyznaczania parametrów obróbki cieplnej odlewów staliwnych

63%

Wróbel J. , Kulawik A.

|

2014

|

tom T. 21, nr 52

201--206

PL

W pracy zastosowano sztuczne sieci neuronowe do określania wymaganej wartości współczynnika przejmowania ciepła od odlewu staliwnego. Wielowarstwowa sztuczna sieć neuronowa wyznacza wartości współczynnika przejmowania, tak aby uzyskać odpowiednie ułamki faz w wewnętrznych węzłach kontrolnych odlewu. Wartości tego współczynnika wyznaczane są dla kontrolnych węzłów brzegowych i są aproksymowane na pozostałe elementy brzegowe. Dane uczące oraz testowe uzyskano z rozwiązania równania przewodzenia ciepła z wykorzystaniem metody elementów skończonych (zadania 2D). Ułamki faz wyznaczono z zastosowaniem makroskopowego modelu przemian fazowych w stanie stałym (analiza wykresów CTP).Przedstawiono błędy opracowanej metody oraz jej skuteczność w automatyzacji projektowania procesu chłodzenia.

EN

n the paper the artificial neural network to determine value of heat transfer coefficient (α∞) for the steel casting has been used. On the basis of phase fraction in the control nodes which were located in the area of casting the required values of heat transfer coefficient have been determined by the multilayer artificial neural network. The values of α∞coefficient are set down for the boundary control nodes and approximated on the other elements. On the basis of numerical solution of the thermal conductivity equation with finite element method the learning and testing data have been obtained (2D tasks). The macroscopic model of phase transformations in the solid state (analysis of CCT diagrams) has been used to calculate the phase fractions. In this paper the errors of implemented method and the effectiveness of this method in automatization of the optimization for the cooling process are presented.