Wyniki wyszukiwania - BazTech

1

Modelling of impact of temperature gradient on content of polymer ampoule during its forming

Koloskova G. M., Koloskov V. Yu.

Journal of Achievements in Materials and Manufacturing Engineering

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2020

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Vol. 100, nr 1

12--19

EN

Purpose: The aim of the represented study was to model the impact of temperature gradient on content of polymer ampoule during its forming. Design/methodology/approach: The model of polymer ampoules forming is built in SolidWorks software on the basis of finite element method. Using the developed model the study of temperature condition changes is carried out. Numerical modelling was carried out for two types of polymer packaging materials – polypropylene and polyvinylchloride – in similar conditions. Findings: During polymer ampoule forming the highest temperature of liquid is obtained at the bottom of it. The most effective packaging method is to form the ampoule from polypropylene by means of aluminium die. Investigation results have shown that the highest obtained liquid temperature has linear dependence from initial one. Linear coefficients of heating were evaluated for polypropylene (equal to 0.72) and polyvinylchloride (equal to 0.58). Practical implications: Decrease of initial liquid temperature value gives an opportunity to expand the range of products allowed to be packed in polymer ampoules in represented method. Safe conditions for packaging of liquid products in polymer ampoules are formulated, The results of the study may be used to improve the quality of liquid products packaging in polymer ampoules. Originality/value: For the first time the model was developed for determination of liquid heating degree during its packaging in polymer ampoules. The calculations of the temperature distribution are represented for polypropylene and polyvinylchloride ampoules forming by means of aluminium and ceramic dies. The results of the study may be of interest to specialists in the field of polymer packaging manufacturing for food or pharmaceutical industry.

2

Prediction optimization of mechanical properties of ferrite stainless steels after forging treatment with use of genetic algorithms

Honysz R.

Archives of Materials Science and Engineering

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2019

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Vol. 100, nr 1/2

13--20

EN

Purpose: The paper describes the use of artificial neural networks to research and predict the effect of chemical components and thermal treatment conditions on stainless steel's mechanical characteristics optimized by genetic algorithm. Design/methodology/approach: The quantity of input variables of artificial neural networks has been optimized using genetic algorithms to enhance the prediction quality of artificial neural network and to enhance their efficiency. Then a computational model was trained and evaluated with optimized artificial neural networks. Findings: Optimization, with the exception of tensile strength, has enabled the creation of artificial neural networks, which either showed a better or similar performance from base networks, as well as a decreased amount of input variables As a consequence, noise data is decreased in the computational model built with the use of these networks. Research limitations/implications: Data analysis was required to confirm the relevance of obtaining information used for modelling to use in training procedures for artificial neural networks. Practical implications: Using artificial intelligence enables the multi-faceted growth of stainless steel engineering, even though there is only a relatively small amount of descriptors. Built and optimized computational model building using optimized artificial neural networks enables prediction of mechanical characteristics after normalization of forged ferritic stainless steels. Originality/value: In order to decrease production expenses of products, an introduced model can be obtained in manufacturing industry. It can also simplify the selection of materials if the engineer has to correctly choose chemical elements and appropriate plastics and/or heat processing of stainless steels, having the necessary mechanical characteristics.

3

Modelling of stresses and strains in two-layer combined materials at their formation

Koloskova G. M.

Archives of Materials Science and Engineering

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2019

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Vol. 97, nr 1/2

12--19

EN

Purpose: The aim of the represented study was to model the behaviour of two-layer combined material during its manufacturing. Design/methodology/approach: The model of material layers joining by means of calender method is built in LS-DYNA software on the basis of finite element method. Using the developed model the study of stress and strain condition changes is carried out. Numerical modelling was carried out for two types of two-layer combined materials in similar conditions. First combination was of high-density polyethylene top layer and aluminium foil bottom layer. Second combination was of high-density polyethylene top layer and low- density polyethylene bottom layer. Joining materials had equal thicknesses. Findings: During formation of two-layer combined materials the primary strain always occurs at the bottom plate of the bottom layer. However, the maximum plastic strain will be represented for the layer with lower elastic modulus value. At the point of the highest loading applied to the two-layer combined material the elasticity condition is changed to the plasticity one and the yield process is registered. Practical implications: Multi-layer combined materials are some of the most advanced types of materials. The quality of the joining of the layers, the strains and the stresses arising in their manufacturing process are the main causes of low interlayer strength. It leads to easy exfoliation and destruction of the material. The results of the study may be used to improve the quality of multi-layer combined materials. Originality/value: For the first time the model was developed for the determination of strains and stresses arising during the formation of multi-layer combined materials by means of calendering method. The calculations of the stresses and strains distribution dynamics for two-layer combined materials are represented for polymer-metal and polymer-polymer layers combinations. The results of the study may be of interest to specialists in the field of multi-layer combined materials designing and manufacturing.

4

Virtual laboratory methodology in scientific researches and education

Honysz R., Dobrzański L. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2017

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Vol. 84, nr 2

76--84

EN

Purpose: This article is presenting the Material Science Virtual Laboratory. Developed laboratory is an open scientific, investigative, simulating and didactic medium helpful in the realisation of the scientific and didactic tasks in the field of material Science. It is implemented in the Institute of Engineering Materials and Biomaterials of Silesian University of Technology in Gliwice, Poland. Design/methodology/approach: The laboratory is a set of testers and training simulators, set in the Virtuality and created in several languages and the programming techniques, which interprets the properties, functionality and manual rules of actual equipment installed and accessible in the real science labs of scientific universities. Findings: Application of the equipment, that is practically imperishable, cheap in exploitation and ease in the use encourages students and scientific workers to independent audits and experiments in places, where the possibilities of their performance in the real investigative laboratory will be restricted because of the high material costs, difficult access to real equipment or the possible peril of his impairment. Research limitations/implications: The proposed solutions allow the utilisation of the developed virtual environment as a new medium in both, the scientific work performed remotely, as well as in education during classes. Practical implications: The usage possibilities of the virtual laboratory are practically unrestricted; it can be a foundation for any surveys, course or training plan. Originality/value: The project of the virtual laboratory corresponds with the global tendency for expand the investigative and academic centres about the possibilities of training and experiments performance with use of the virtual reality. This enriches investigation and training programmes of the new abilities reserved so far exclusively for effecting only on actual equipment.

5

Numerical analysis of the cavitation effect occurring on the surface of steel constructional elements

Linek T., Tański T., Borek W.

Archives of Materials Science and Engineering

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2017

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Vol. 85, nr 1

24--34

EN

Purpose: The aim of the work is to present the results of own investigations concerning the geometric optimisation of constructional elements working in the environment of cavitation wear together with a computer numerical analysis. The engineering material used for constructional elements working in the environment of cavitation wear is steel, commonly used for pressure devices working at elevated temperatures, P265GH, acc. to PN-EN 10028:2010. Design/methodology/approach: SOLID EDGE ST 7 software, for synchronous designing, was used for the parametrisation of the shape, distribution, configuration and size of openings in constructional elements. Five models, with a different spacing and number of openings, were proposed for the optimisation of internal geometry of the cavitation generator and for the investigations; the models were then subjected to a numerical analysis using specialised software, ANSYS FLUENT v.16, employed for modelling the effects associated with fluid mechanics (Computational Fluid Dynamics - CFD). The data was implemented for this purpose in the software used, such as: density, yield point, tensile strength, heat conductivity coefficient for steel P265GH, material surface roughness, medium (water) flow rate, constant pressure loss of medium, pressure of steam saturation in a medium; and such data was called boundary conditions. Findings: The authors’ principal accomplishment is the optimisation of the shape, the selection of the most appropriate geometry of a constructional element generating the maximum number of cavity implosions in the environment of a flowing medium (water), with the use of computer tools dedicated to engineering design: a 3D and numerical computer analysis of fluid mechanics, CFD. Moreover, an attempt was made in this work to develop a methodology for characterisation of the phenomena accompanying the environment of cavitation wear. Practical implications: A possibility of examining the phenomena and a process of wear of a constructional element made of P265GH grade steel for pressure devices working at elevated temperatures. The demonstration and presentation of potential places, areas and sizes of erosion existing on constructional elements working in the environment of cavitation wear.

6

Neural networks model for prediction of the hardness of steels cooled from the austenitizing temperature

Trzaska J.

Archives of Materials Science and Engineering

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2016

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Vol. 82, nr 2

62--69

EN

Purpose: The paper presents the new neural networks model making it possible to estimate the hardness of continuously-cooled steel from the austenitizing temperature. Design/methodology/approach: The method proposed in the paper employs two applications of the neural networks of: classification and regression. Classification and consists in determining the value of dichotomous variables describing the occurrence of: ferrite, pearlite, bainite and martensite in the microstructure of a steel. The values of dichotomous variables have been used for calculating steel hardness. The other task is regression, which aims at calculating the steel hardness. Findings: The presented neural networks model can be used only in the range of concentrations of alloying elements shown in this paper. Practical implications: The model worked out makes it possible to calculate hardness for the steel with a known chemical composition. This model deliver important information for the rational selection of steel for those parts of the machines that are subjected to the heat treatment. The presented model make it possible the analysis of the interaction of the chemical composition on the hardness curves of the steel cooled from the austenitizing temperature. Originality/value: The paper presents the method for calculating hardness of the structural and engineering steels, depending on their chemical composition, austenitizing temperature and cooling rate.

7

The application of neural networks to analysis of the effects of chemical composition on hardenability of steel

Sitek W., Jabłoński A.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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Vol. 72, nr 1

32--38

EN

Purpose: The goal of the research carried out was evaluation of alloying elements effect on the development of artificial neural network models, allowing the determination of the Jominy hardenability curve based on the chemical composition of constructional and machine steels. Design/methodology/approach: MLP neural network was used to learn rule for modelling the steels properties. Then the neural network used for computer simulation synergistic effect of alloying elements on the hardenability of steel. Research limitations/implications: Results of the research confirmed that neural networks are a useful tool in evaluation the effect of alloying elements on the properties of materials compared to conventional methods. Additionally it confirms idea, that based on data from standards and catalogues is possible to develop the assumed model. Practical implications: It has been demonstrated complete the practical usefulness of the developed models in the selection of materials designed machine parts, which allows the direct relationship during the melting process real time control of the desired hardness of the steel hardenability curve. Originality/value: Based on the results of catalogues and standards with the used of neural networks developed and fully validated experimental model of the relationship between hardenability and chemical composition of the constructional and machine steels.

8

Prediction optimization of mechanical properties of ferrite stainless steels after rolling treatment with use of genetic algorithms

Honysz R.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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Vol. 68, nr 1

17--24

EN

Purpose: The article discusses the use of artificial neural networks for research and prediction of the impact of chemical elements and heat treatment parameters on the mechanical properties of stainless steels optimized by genetic algorithm. Design/methodology/approach: To improve the quality of artificial neural network models and improve their performance the number of input variables of artificial neural networks has been optimized with use of genetic algorithms. Then a computational model build with optimised artificial neural networks were trained and verified. Findings: Optimization, except of tensile strength Rm case, has allowed the development of artificial neural networks, which either showed a better or comparable result from base networks, and also have a reduced number of input variables. As a result, in computational model constructed with use of these networks the noise information is reduced. Research limitations/implications: Data analysis was needed to verify if obtained data used for modelling are relevant to use them in artificial neural networks training processes. Practical implications: The use of artificial intelligence allows the multifaceted development of stainless steels engineering, even if only a small number of descriptors is available. Constructed and optimised computational model build with use of optimised artificial neural networks allows prediction of mechanical properties of rolled ferritic stainless steels after normalization. Originality/value: Introduced model can be obtain in industry to reduce manufacturing costs of materials. It can also simplify material selection, when engineer must properly choose the chemical elements and adequate plastic and/or heat treatment of stainless steels with required mechanical properties.

9

Influence of aging time and temperature on diffusion of alloyed copper

Konieczny J., Rdzawski Z., Bańbura P., Preficz B.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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Vol. 73, nr 1

27--35

EN

Purpose: The aim of this study is to determine the impact of aging time and temperature on the diffusion process of alloying elements inside alloyed copper CuCr0,7, CuFe2 and CuTi4. Design/methodology/approach: It was assumed the activation energy for diffusion of small interstitial atoms is smaller than for large substitute atoms. To determine the influence of aging time and temperature on diffusion of alloying elements in binary copper-based alloys CuCr0,7, CuFe2 and CuTi4 it has been necessary to develop a suitable mathematical model. It has been shown that with the increase of time t, the diffusion pathway L is increased, but the impact of time is not as large as the effect forced by altering temperature. In general, multiple increase of time is equivalent to increasing the temperature by a few degrees. Findings: The model should be used to estimate the average atom pathway of chromium, iron or titanium in copper matrix, caused by diffusion, and the diffusion path into the grain boundary without adsorption as a function of time and temperature aging Research limitations/implications: The model should be used to calculate the influence of temperature and time of aging on the atoms diffusion pathway of the alloying elements in the selected alloyed copper types. Practical implications: The results allow to calculate the average atom pathway L (with reasonable error level) for which the diffused atoms achieve the amount of free energy required to overcome the energetic barrier, on the basis of a combination of heat treatment parameters. Originality/value: This paper presents the impact of the aging temperature on diffusion in the alloyed copper CuCr0.7, CuFe2 and CuTi4.

10

Elastic modules identification by layered composite beams testing

Diveyev B., Konyk S.

Journal of Achievements in Materials and Manufacturing Engineering

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2015

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Vol. 72, nr 1

14--22

EN

Purpose: The study aims to predict elastic properties of composite laminated plates from the measured mechanical properties. Design/methodology/approach: Elastic constants of laminates and damping properties have been determined by using an identification procedure based on experiment design, and multi-level theoretical approach. Findings: The present paper is the first attempt at proposing a novel adaptive procedure to derive stiffness parameters from forced sandwich plate’s vibration experiments. Research limitations/implications: In the future the extension of the present approach to sandwich plates with different core materials will be performed in order to test various experimental conditions. Practical implications: Structures composed of laminated materials are among the most important structures used in modern engineering and especially in the aerospace industry. Such lightweight and highly reinforced structures are also being increasingly used in civil, mechanical and transportation engineering applications. Originality/value: The main advantage of the present method is that it does not rely on strong assumptions on the model of the plate. The key feature is that the raw models can be applied at different vibration conditions of the plate by a suitable analytical ore approximation method

11

Optimization of chemical composition and heat treatment condition of structural steel

Honysz R., Dobrzański L. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2014

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Vol. 64, nr 1

27--33

EN

Purpose: This paper presents the methodology and results of virtual research project involving the optimization of the chemical composition and heat treatment conditions of structural steels. Investigations were performed in virtual environment with use of materials science virtual laboratory. Design/methodology/approach: The first task was to search for such a range of chosen element concentration while keeping the concentration of other elements unchanged in order to satisfy all the conditions for steel mechanical properties defined by a virtual client. Second task of virtual research project consisted in searching for such ranges of temperature and time for hardening and tempering , to ensure that all the conditions for steel properties defined by a virtual client has been met without making changes in the chemical composition of steel. Findings: Virtual investigations results were verified in real investigative laboratory. Results of virtual examinations are presented as raw data and influence charts. Practical implications: The new material design methodology has practical application in the development of materials and modelling of steel descriptors in aim to improve the mechanical properties and specific applications in the production of steel. Presented examples of computer aid in structural steel production shows a potential application possibility of this methodology to support the production of any group of engineering materials. Originality/value: The prediction possibility of the material mechanical properties is valuable for manufacturers and constructors. It ensures the customers quality requirements and brings also measurable financial advantages.

12

Calculation of volume fractions of microstructural components in steels cooled from the austenitizing temperature

Trzaska J.

Journal of Achievements in Materials and Manufacturing Engineering

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2014

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Vol. 65, nr 1

38--44

EN

Purpose: The paper presents method in predicting the volume fractions of ferrite, pearlite, bainite and martensite of steel cooled continuously from the austenitizing temperature, basing on the chemical composition, austenitizing temperature and cooling rate. Design/methodology/approach: In the paper it has been applied a hybrid approach that combined application of various mathematical tools including logistic regression and multiple regression to solve selected tasks from the area of materials science. Findings: Computational methods are an alternative to experimental measurement in providing the material data required for heat treatment process simulation.Research limitations/implications: All equations are limited by range of mass concentrations of elements which is presented in Table 2. Practical implications: The worked out formulae may be used in computer systems of steels’ designing for the heat-treated machine parts. Originality/value: The paper presents the method for calculating the volume fractions of ferrite, pearlite, bainite and martensite of the structural steels, depending on their chemical composition, austenitizing temperature and cooling rate.

13

The influence of fill factor on the phononic crystal eigenfrequencies

Gruszka K., Nabiałek M., Szota M.

Archives of Materials Science and Engineering

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2014

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Vol. 66, nr 2

74--80

EN

Purpose: The aim of this article is to determine the effect of basic cell fill factor change on the eigenfrequencies observed in two-dimensional phononic crystal. Design/methodology/approach: To perform simulation, the FDFD (finite difference frequency domain) algorithm was used. On this basis, the search for eigenfrequencies was carried out starting from lowest possible acoustic frequency range (~20 Hz) and limited to first nine search results found (up to nearly 2.2 kHz) for increasing fill factor while maintaining the shape of a rod inside cell. Findings: The fill factor has a significant influence on the eigenfrequencies of the studied system when the frequency is above 1 kHz. With the increase of this factor at relatively low frequencies (less than 1 kHz in this case) there were no major changes observed. Research limitations/implications: The results were found only for specific system consisting of materials with similar sound velocity. Therefore, more research should be carried out for other cases i.e. taking into account the different topology of primary cells and various materials with other propagation velocity of acoustic waves in these mediums. Practical implications: Simulation of two-dimensional phononic crystal systems allows for designing new specialized multi-component materials with various acoustic properties. These systems can be adapted in a variety of applications, including acoustic filters, slow-wave devices, acoustic autocollimators and many other. Originality/value: Basic research allow to improve the quality of knowledge on more advanced problems. For this reason, it is important to know in detail how simple systems work and to determine the basic properties of these systems.

14

Influence of rod diameter on acoustic band gaps in 2D phononic crystal

Gruszka K., Nabiałek M., Szota M.

Archives of Materials Science and Engineering

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2014

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Vol. 68, nr 1

24--30

EN

Purpose: The purpose of this paper is to investigate influence of changing the fill factor (or rod diameter) on acoustic properties of phononic crystal made of mercury rods inside of water matrix. Change in construction of primary cell without changing the shape of rod may cause shifts in bands leading to widening of forbidden band gaps, which is the basis of modern composite material designing process. Design/methodology/approach: Band structure is determined by using the finite element study known as finite difference frequency domain simulation method. This is achieved by virtual construction and simulation of primary cell of phononic crystal. Phononic crystals are special devices which by periodic arrangement of properties related to the sound can affect the transmission of acoustic waves thru their body. Findings: The fill factor/rod diameter has a significant influence on the acoustic band structure of studied phononic crystal which can be divided in two mainly effects: fission and compression of band structure. Research limitations/implications: In order to better understand basic properties of phononic crystals and to get full control over the band gaps a series of similar calculations should be done for broader range of frequencies covering both infrasound and ultrasound wavelength regions. Also structures of other cut shape of rod and different primary cell structure resulting in diverse phononic crystal structure should be investigated in the future. Practical implications: Phononic crystals are important devices in variety of applications ranging from noise control through acoustic computing, health applications and entertainment up to military applications. Therefore full knowledge about specific working conditions and elementary properties is necessary for complete control in targeted applications. Controlling the fill factor is one of the simplest methods to achieve specific band gap positions and widths. Originality/value: The novelty is in use of different phase materials with similar acoustic characteristics affecting the hole sonic properties of device manifested by their calculated band structure. The target group are scientists interested in practical applications of various acoustic materials.

15

Strain field analysis in nanoindentation test of gradient coatings

Szparaga Ł., Ratajski J., Bartosik B.

Archives of Materials Science and Engineering

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2013

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Vol. 64, nr 2

219--227

EN

Purpose: In the paper strain distributions within TiAlN/TiN gradient coatings in nanoindentation test were analysed. The main goal was to examine the influence of the type of a gradient layer on strain distributions in the area of the indenter/coating. Design/methodology/approach: For physical modelling purposes Cr, TiN and TiAlN layers were treated as a continuous medium. Basing on this simplification for the mathematical description of the strain states in the coating a classical theory of stiffness was used. Gradient layers were modelled using the conception of transition function which describe continuous physico-chemical material parameters changes in each layer in the multilayer coating. The computer analysis of the strain fields in the coating after deposition process was done vie FEM method. Findings: For a chosen types of gradient coatings the strain distributions in the coating under external loads (nanoindentation test) were calculated. Using created examples of transition functions, the influence of the shape of the function on strain isolines in the area of the indenter/coating was examined. Research limitations/implications: The main simplification which was done during creation of the mathematical model was an assumption that the coating and the substrate are continuous media. This assumption causes that some physical effects occurring during experimental nanoindentation test can not be properly described in a computer model. Also there are numerous mathematical models of contact, so obtained numerical results (strain distributions) strongly depend of the postulated contact model. Practical implications: For a practical implications of the obtained results one should include a mathematical description of the strain states in the nanoindentation test of gradient coatings. The stress and strain fields analysis is extremely important in respect of fracture analysis. It should be also emphasis, that proposed mathematical description of gradient layer using transition function conception is an easy way to represent physical and chemical properties of gradient coating in computer models. The advantage of such a description of gradient layers can be used for example in polyoptimization process of multilayer gradient coatings. Originality/value: The main value of the paper is the comparison study of strain distribution in nanoindentation test of three different gradient coatings represented be three types of transition functions: (a) step function, (b) linear function and (c) modified non symmetrical sigmoidal function.

16

Calculation of the steel hardness after continuous cooling

Trzaska J.

Archives of Materials Science and Engineering

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2013

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Vol. 61, nr 2

87--92

EN

Purpose: The paper presents method in predicting hardness of steel cooled continuously from the austenitizing temperature, basing on the chemical composition, austenitizing temperature and cooling rate. Design/methodology/approach: In the paper it has ©been applied a hybrid approach that combined application of various mathematical tools including logistic regression and multiple regression to solve selected tasks from the area of materials science. Findings: Modelling make improvement of engineering materials properties possible, as well as prediction of their properties, even before the materials are fabricated, with the significant reduction of expenditures and time necessary for their investigation and application. Practical implications: The worked out relationships may be used in computer systems of steels’ designing for the heat-treated machine parts. Originality/value: The paper presents the method for calculating hardness of the structural steels, depending on their chemical composition, austenitizing temperature and cooling rate.

17

Informative technologies in the material products designing

Dobrzański L., Honysz R.

Archives of Materials Science and Engineering

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2012

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Vol. 55, nr 1

37-44

EN

Purpose: The purpose of materials products designing is to optimize their functional properties in terms of technological, economic and ecological aspects. Design/methodology/approach: Materials science is an example of a field, in which informative technologies used to understand and anticipate the construction of materials and their properties has a significant success. Findings: Innovation and development of new informative technologies and the widespread use of modern materials will be essential for promoting economic development in the near future by application of entirely new, interdisciplinary field of science: computational materials science. Practical implications: The use of informative technologies allows exploring in a short time and at low expense, many solutions for the design of the mechanical properties of materials and their simulation beyond the standardized range. Originality/value: The most important benefit of material designing is the ability of suitable selection of material (or its manufacturing) for various applications with use of informative technologies.

18

Fractal and multifractal characteristics of the PVD and CVD coatings deposited onto compound tool ceramics

Kwaśny W., Mikuła J.

Archives of Materials Science and Engineering

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2012

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Vol. 56, nr 1

37-44

EN

Purpose: The goal of this work is the fractal and multifractal characteristics of the TiN and TiN+multiTiAlSiN+TiN coatings obtained in the PVD process, and of the TiN+Al2O3 coating obtained in the CVD process on the Al2O3+TiC oxide tool ceramics substrate. Design/methodology/approach: The investigations were carried out of the multi-edge inserts from the Al2O3+TiC oxide tool ceramics uncoated and coated with the TiN and TiN+multiTiAlSiN+TiN coatings deposited in the cathode arc evaporation CAE PVD process, as well as with the TiN+Al2O3 coating obtained in the CVD process. Determining the fractal dimension and the multifractal analysis of the examined coatings were made basing on measurements obtained from the AFM microscope, using the projective covering method. Findings: Investigations carried out confirm that the fractal dimension and parameters describing the multifractal spectrum shape may be used for characterizing and comparing surfaces of coatings obtained in the PVD and CVD processes and of the substrate material from the Al2O3+TiC. Research limitations/implications: Investigation or relationship between parameters describing the multifractal spectrum and physical properties of the examined materials calls for further analyses. Originality/value: Investigations carried out confirm that the fractal dimension and parameters describing the multifractal spectrum shape may be used for characterizing and comparing surfaces of coatings obtained in the PVD and CVD processes.

19

Computer modelling of ductile iron solidification using FDM and CA methods

Kapturkiewicz W., Burbelko A. A., Fraś E., Górny M., Gurgul D.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 43, nr 1

310--323

EN

Purpose: The purpose of the work was the presentation of tool for modelling of solidification process, for prediction of some structure parameters in DI by the given chemical composition of alloy and for given boundary condition of casting. Design/methodology/approach: Two mathematical models and methods developed by authors have been presented: micromodelling with using of finite difference method (FDM) and mesomodelling with using of cellular automaton method (CA). Findings: The FDM was used for solving the DI solidification model, including heat conductivity equation with source function, boundary condition for casting, equations for austenite and eutectic grains nucleation depended on the changing undercooling, the Weibull’s formula for graphite nodule count, Kolmogorov’s equation for calculation of volume fraction of phases (eutectics and austenite). A set of equations, after transformation to a difference form, were solved by the finite difference method, using an iteration procedure. The correctness of the mathematical model has been experimentally verified in the range of most significant factors, which include temperature field, the value of maximum undercooling, and the graphite nodule count interrelated with the casting cross-section. Literature offers practically no data on so confronted process model and simulation program. The CA model was used for the simulation of the grains’ shapes in connection with FD for temperature field and solute redistribution in the grain scale. Practical implications: FDM modeling gives the possibility of statistical description of microstructure but the geometrical shape of grains is assumed a priori. In CA modeling the grain shape is not assumed, but this is the result of modeling. The use of FDM gives results quantitatively comparable to the process in real casting, particularly according to temperature fields and number of graphite spheroids. Originality/value: The CA method gives on the present stage credible qualitative results but this method is more perspective for good reproducing of the real process of solidification.

20

Computer simulation of stresses in coatings obtained in the PVD process

Śliwa A., Kwaśny W., Dobrzański L. A.

Inżynieria Materiałowa

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2010

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Vol. 31, nr 3

732-734

EN

The paper presents application of the Finite Element Method for determining the internal stresses occurring in the Ti+Ti(Al,N) coatings obtained in the magnetron PVD process on the PM HS6-5-3-8 type sintered high-speed steel. The model was developed using FEM, relevant for the investigated test pieces, for the computer simulation of the internal stresses in coatings, which was verified experimentally by comparing the calculation results with the experimental results.

PL

W pracy przedstawiono zastosowanie metody elementów skończonych do wyznaczania naprężeń własnych występujących w powłokach Ti + Ti- (Al, N), uzyskanych w magnetronowym procesie PVD na spiekanej stali szybkotnącej PM HS6-5-3-8. Dla celów symulacji komputerowej naprężeń własnych w powłokach z wykorzystaniem MES opracowano odpowiedni dla analizowanych próbek model, który poddano weryfikacji doświadczalnej, dokonując porównania wyników obliczeń z wynikami badań eksperymentalnych.