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1

Methodology of high-speed steels design using the artificial intelligence tools

Sitek W.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 39, nr 2

115-160

EN

Purpose: The main goal of the research carried out was developing the design methodology for the new high-speed steels with the required properties, including hardness and fracture toughness, as the main properties guaranteeing the high durability and quality of tools made from them. It was decided that hardness and fracture toughness KIc are the criteria used during the high-speed steels design. Design/methodology/approach: In case of hardness, the statistical and neural network models were developed making computation possible of the high-speed steel hardness based solely on the steel chemical composition and its heat treatment parameters, i.e., austenitizing- and tempering temperatures. In this case results of own work on the effect of alloy elements on the secondary hardness effect were used, as well as data contained in catalogues and pertinent standards regarding the high-speed steels. In the second case - high-speed steels fracture toughness, the neural network model was developed, making it possible to compute the KIc factor based on the steel chemical composition and its heat treatment parameters. The developed material models were used for designing the chemical compositions if the new high-speed steel, demonstrating the desired properties, i.e., hardness and fracture toughness. Methodology was developed to this end, employing the evolutionary algorithms, multicriteria optimisation of the high-speed steels chemical composition. Findings: Results of the research carried out confirmed the assumption that using the data from catalogues and from standards is possible, which - would supplement the set of data indispensable to develop the assumed model - improving in this way its adequacy and versatility. Practical implications: Solutions presented in the work, based on using the adequate material models may feature an interesting alternative in designing of the new materials with the required properties. The practical aspect has to be noted, resulting form the developed models, which may successfully replace the above mentioned technological investigations, consisting in one time selection of the chemical composition and heat treatment parameters and experimental verification of the newly developed materials to check of its properties meet the requirements. Originality/value: The presented approach to new materials design, being the new materials design philosophy, assumes the maximum possible limitation of carrying out the indispensable experiments, to take advantage of the existing experimental knowledge resources in the form of databases and most effective computer science tools, including neural networks and evolutionary algorithms. It should be indicated that the materials science knowledge, pertaining oftentimes to the multi-aspect classic problems and described, or - rather - saved in the existing, broadly speaking, databases, features the invaluable source of information which may be used for discovery of the unknown so far relationships describing the material structure - properties relations.

2

FEM application for modelling of PVD coatings properties

Śliwa A., Mikuła J., Dobrzański L. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 41, nr 1-2

164-171

EN

Purpose: The general topic of this paper is problem of determining the internal stresses of composite tool materials with the use of finite element method (FEM). The chemical composition of the investigated materials’ core is corresponding to the M2 high-speed steel and was reinforced with the WC and TiC type hard carbide phases with the growing portions of these phases in the outward direction from the core to the surface. Such composed material was sintered, heat treated and deposited appropriately with (Ti,Al)N or Ti(C,N) coatings. Design/methodology/approach: Modelling of stresses was performed with the help of finite element method in ANSYS environment, and the experimental values of stresses were determined basing on the X-ray diffraction patterns. The computer simulation results were compared with the experimental results. Findings: Computer aided numerical analysis gives the possibility to select the optimal parameters for coatings covering in PVD process determining the stresses in coatings, employing the finite element method using the ANSYS software. Research limitations/implications: It was confirmed that using of finite element method in stresses modelling occurring in advanced composite materials can be a way for reducing the investigation costs. In order to reach this purpose, it was used in the paper a simplified model of composite materials with division on zones with established physical and mechanical properties. Results reached in this way are satisfying and in slight degree differ from results reached by experimental method. Originality/value: Nowadays the computer simulation is very popular and it is based on the finite element method, which allows to better understand the interdependence between parameters of process and choosing optimal solution. The possibility of application faster and faster calculation machines and coming into being many software make possible the creation of more precise models and more adequate ones to reality.

3

Experimental and numerical studies of MR damper with prototype magnetorheological fluid

Kciuk S., Turczyn R., Kciuk M.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 39, nr 1

52-59

EN

Purpose: Results of experimental studies of a prototype magnetorheological damper at various magnitudes of control current as well as the manner of modelling electromagnetic phenomena occurring in the damper are presented in this paper. Design/methodology/approach: Model MR fluid was prepared using silicone oil OKS 1050 mixed with carbonyl iron powder CI. Furthermore, to reduce sedimentation, as stabilizers was added Aerosil 200. The observations of the surface morphology of carbonyl iron and fumed silica were carried out using Digital Scanning Electron Microscope SUPRATM25 ZEISS. The effect of magnetic field on magnetorheological fluid is modelled by the finite element method. Findings: The presented model meets the initial criteria, which gives ground to the assumption about its usability for determining the dynamics properties of mechanical systems, employing the finite element method using ANSYS software. Research limitations/implications: The elaborated model can be use for modelling the semi active car suspension dynamics. Originality/value: The actual-non-linear characteristics of magnetisation identified experimentally were used as the values of relative magnetic permeability of the piston housing material. The possibility of application, e.g. real characteristics of material magnetisation and faster and faster calculation machines make possibility the creation of more precise models and more adequate ones to reality.

4

Computer models of steam pipeline components in the evaluation of their local strength

Okrajni J., Essler W.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 39, nr 1

71-78

EN

Purpose: The paper discusses the issue of modelling the heating and cooling processes of T-pipes in a power plant pipeline in the start-up conditions of a boiler. The main purpose of this work is the description of the mechanical behaviour of power plant components working under mechanical and thermal loading and validation of the computer modelling methods. Design/methodology/approach: The FEM modelling has been used to describe the local stress-strain behaviour of the chosen component. Findings: The reasons for the presence of high and variable in time temperature gradients in the components of the main steam pipeline include, among other things, variable values of the coefficient of heat transfer between the pipeline material and the medium flowing inside it, which, at this stage of boiler operation, may change its state. Unsteady operation of a pipeline, especially in case of subsequent boiler start-ups, may induce thermal stresses which exceed the values of allowable stress in components of complex shapes. Research limitations/implications: The possibility of applying the durability criteria currently assumed in standards still requires justification and confirmation in laboratory and industrial conditions to be closer to the real components behaviour. In such situation the presented analysis is the part of the complex investigation method which main purpose is increasing accuracy of the TMF process description and thermo-mechanical life assessment. Practical implications: The calculations carried out may constitute a basis for developing a material test parameters which would bring closer the fatigue conditions appearing locally in the analysed components. The method of stress-strain behaviour analysis used in the paper could be useful in the practical cases when the real components mechanical behaviour would be analysed. Originality/value: The main value of this paper is the own method of the mechanical behaviour analysis of the power plant component. This method includes the temperature fields analysis taking into account the boundary conditions based on the operation parameter data and the thermoplastic material model. The material stress-strain behaviour has been treated as the local phenomenon, that could be modelled by FEM.

5

Application of FEM for solving various issues in material engineering

Dobrzański L. A., Pusz A., Nowak A. J., Górniak M.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 42, nr 1-2

134-141

EN

Purpose: The aim of this work is to present selected problems concerning the application of Finite Element Method in materials engineering on the example of chosen program which makes the most of this method to simulation. Design/methodology/approach: Application of Finite Element Method was discussed and essential advantages resulting from application of it are pointed. Findings: Description of the importance and the utility of FEM during solving of problems dealing with very complicated geometry complex state of loadings, various boundary conditions and/or various materials. Research limitations/implications: The method must be applied very carefully because its results do not refer to real system but only to the model one. The obtained results of FEM calculations can be used to solve many problems at the early step of designing with success. Originality/value: The application of FEM method during working out the internal prosthesis of oesophagus which will enable help people suffering from oesophageal cancer.

6

Application of artificial neural networks in modelling of quenched and tempered structural steels mechanical properties

Dobrzański L. A., Honysz R.

Journal of Achievements in Materials and Manufacturing Engineering

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2010

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Vol. 40, nr 1

50-57

EN

Purpose: This paper presents the application of artificial neural networks for mechanical properties prediction of structuralal steels after quenching and tempering processes. Design/methodology/approach: On the basis of input parameters, which are chemical composition, parameters of mechanical and heat treatment and dimensions of elements, steels’ mechanical properties : yield stress, tensile strength stress, elongation, area reduction, impact strength and hardness are predicted. Findings: Results obtained in the given ranges of input parameters indicates on very good ability of artificial neural networks to values prediction of described mechanical properties for steels after quenching and tempering processes. The uniform distribution of descriptive vectors in all, training, validation and testing sets, indicates on good ability of the networks to results generalisation. Practical implications: Artificial neural networks, created during modelling, allows easy prediction of steels properties and allows the better selection of both chemical composition and the processing parameters of investigated materials. It’s possible to obtain steels, which are qualitatively better, cheaper and more optimised under customers needs. Originality/value: The prediction possibility of the material mechanical properties is valuable for manufacturers and constructors. It allows the preservation of customers quality requirements and brings also measurable financial advantages

7

Thermo-mechanical fatigue conditions of power plant components

Okrajni J.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 33, nr 1

53-61

EN

Purpose: The main purpose of this work is the description of the mechanical behaviour of power plant components working under mechanical and thermal loading that cause the thermo-mechanical fatigue fracture in selected areas of the component surfaces. Design/methodology/approach: The computer modelling has been used to describe the local stress-strain behaviour of the chosen component. Findings: The values of variable in time temperature strains and stresses in selected points of the power plant header were determined. The points were located at the edges of holes through which water steam is supplied and carried away, where under use conditions the presence of cracks can be observed. That stresses and mechanical strains caused by the influence of a non-uniform temperature field may be significantly higher in comparison with the stresses and strains caused by the pressure inside the analysed component. Tensile thermal stresses of high values are created especially under conditions of sudden cooling during unsteady work of a power unit. Research limitations/implications: The possibility of applying the durability criteria currently assumed in standards still requires justification and confirmation in laboratory and industrial conditions to be closer to the real components behaviour. In such situation the presented analysis is the part of the complex investigation method which main purpose is increasing accuracy of the TMF process description and thermo-mechanical life assessment. Practical implications: The calculations carried out may constitute a basis for developing a material test parameters which would bring closer the fatigue conditions appearing locally in the analysed components. The method of stress-strain behaviour analysis used in the paper could be useful in the practical cases when the real components mechanical behaviour would be analysed. Originality/value: The main value of this paper is the own method of the mechanical behaviour analysis of the power plant component. This method includes the temperature fields analysis taking into account the boundary conditions based on the operation parameter data and the thermoplastic material model. The material stress-strain behaviour has been treated as the local phenomenon, that could be modelled by FEM.

8

Finite Element Method application during powder injection moulding

Śliwa A., Matula M., Dobrzański L. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 37, nr 2

584-591

EN

Purpose: The general topic of this paper is problem of model ling of a polymer-powder mix flow during filling, in which the high-speed steel was used along with paraffin and polypropylene as a binding agent. Design/methodology/approach: Modelling of the polymer-powder mix flow process during filling was performed using the finite element method in Cadmould environment; polymer-powder mix was injection moulded using Arburg injection moulder. Computer simulation results were compared with experimental results. Findings: The presented model meets the initial criteria, which gives ground to the assumption about its usability for injection moulding of polymer-powder slurry process, employing the finite element method using the Cadmould software. The computer simulation results correlate with the experimental results. Research limitations/implications: It was confirmed that using of finite element method in powder injection moulding process can be a way for reducing the investigation costs Results reached in this way are satisfying and in slight degree differ from results reached by experimental method. However for achieving better calculation accuracy in further researches it should be developed given model which was presented in this paper. Originality/value: Nowadays the computer simulation is very popular and it is based on the finite element method, which allows to better understand the interdependence between parameters of process and choosing optimal solution. The possibility of application faster and faster calculation machines and coming into being many software make possible the creation of more precise models and more adequate ones to reality

9

FEM modelling of internal stresses in PVD coated FGM

Śliwa A., Mikuła J., Gołombek K., Dobrzański L. A.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 36, nr 1

71-78

EN

Purpose: The general topic of this paper is problem of determining the internal stresses of composite gradient tool materials with the use of finite element method (FEM). The chemical composition of the investigated materials’ core is corresponding to the M2 high-speed steel and was reinforced with the WC and TiC type hard carbide phases with the growing portions of these phases in the outward direction from the core to the surface. Such composed material was sintered, heat treated and deposited appropriately with (Ti,Al)N or Ti(C,N) gradient coatings. Design/methodology/approach: Modelling of stresses was performed with the help of finite element method in PATRAN environment, and the experimental values of stresses were determined basing on the X-ray diffraction patterns. The computer simulation results were compared with the experimental results. Findings: The presented model meets the initial criteria, which gives ground to the assumption about its usability for determining the stresses in coatings, employing the finite element method using the PATRAN software. The computer simulation results correlate with the experimental results. Research limitations/implications: It was confirmed that using of finite element method in stresses modelling occurring in gradient- structured materials can be a way for reducing the investigation costs. In order to reach this purpose, it was used in the paper a simplified model of gradient- structured materials with division on zones with established physical and mechanical properties. Results reached in this way are satisfying and in slight degree differ from results reached by experimental method. However for achieving better calculation accuracy in further researches it should be developed given model which was presented in this paper. Originality/value: Nowadays the computer simulation is very popular and it is based on the finite element method, which allows to better understand the interdependence between parameters of process and choosing optimal solution. The possibility of application faster and faster calculation machines and coming into being many software make possible the creation of more precise models and more adequate ones to reality.

10

Computer modelling system of the chemical composition and treatment parameters influence on mechanical properties of structural steels

Dobrzański L. A., Honysz R.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 35, nr 2

138-145

EN

Purpose: This paper presents Neuro-Lab. It is an authorship programme, which use algorithms of artificial intelligence for structural steels mechanical properties estimation. Design/methodology/approach: On the basis of chemical composition, parameters of heat and mechanical treatment and elements of geometrical shape and size this programme has the ability to calculate the mechanical properties of examined steel and introduce them as raw numeric data or in graphic as influence charts. Possible is also to examine the dependence among the selected steel property and chosen input parameters, which describes this property. Findings: There is no necessity of carrying out any additional material tests. The results correlations between calculated and measured values are very good and achieve even the level of 98%. Practical implications: Presented programme can be an effective replace of the real experimental methods of properties determination in laboratory examinations. It can be applied as the enlargement of experimental work. Possible is also the investigation of models coming from new steel species, that wasn’t produced yet. Originality/value: The ability of the mechanical properties estimation of the ready, or foreseen to the use, material is unusually valuable for manufacturers and constructors. This signifies the fulfilment of customer’s quality requirements as well as measurable financial advantages for material manufacturers.

11

Application of artificial neural networks in modelling of normalised structural steels mechanical properties

Dobrzański L. A., Honysz R.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 32, nr 1

37-45

EN

Purpose: This paper presents the application of artificial neural networks for mechanical properties prediction of structural steels after heat treatment. Design/methodology/approach: On the basis of such input parameteres, which are the chemical composition, the kind of mechanical and heat treatment and dimensions of elements, mechanical properties, such as strength, impact resistance or hardness are predicted. Findings: Results obtained in the given ranges of input parameters show very good ability of constructed neural networks to predict described mechanical properties for steels after heat treatment. The uniform distribution of descriptive vectors in all, training, validation and testing sets, indicate about the good ability of the networks to results generalisation. Practical implications: Created tool makes possible the easy modelling of described properties and allows the better selection of both chemical composition and the processing parameters of investigated materials. At the same time the obtainment of steels, which are qualitatively better, cheaper and more optimised under customers needs is made possible. Originality/value: The prediction possibility of the material mechanical properties is valuable for manufacturers and constructors. It allows preserving the customers quality requirements and brings also measurable financial advantages.