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of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

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Author: Tontchev N.

  • MATERIALS

    APPLICATION OF CAD DESIGN OF TECHNOLOGICAL PROCESSES IN THE FIELD OF MATERIAL SCIENCE

    • Yankov E. Hr.
    • Tontchev N.
    • Yonchev S.
    Machines. Technologies. Materials., Vol. 11 (2017), Issue 12, pg(s) 595-598
    • Abstract
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    •  Article PDF

    A review of the existing methods applied to multi-criteria decision aiding has been made as well as the multi-criteria approach to a class of problems in the field of material science has been defined. The multi-criteria decision aiding has been successfully applied to determine appropriate compromise decisions about the examined parameters of a number of technological processes of welding, chemical thermal processing, iron covering, etc. The approach presented determines the values of technological factors satisfying the requirements of users simultaneously to a number of values examined and proposes a solution for the relatively highest thresholds at one and the same time

  • MATHEMATICAL MODELLING OF TECHNOLOGICAL PROCESSES AND SYSTEMS

    ROBUST BI-CRITERIA APPROACH TO OPTIMIZE THE COMPOSITION AND PROPERTIES OF MAGNESIUM ALLOY

    • Kalev Yo.
    • Hai Hao
    • Tontchev N.
    Mathematical Modeling, Vol. 2 (2018), Issue 1, pg(s) 28-32
    • Abstract
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    •  Article PDF

    The paper presents standard statistical robust bi-criteria procedure for determining expert assessments for the influence of magnesium alloy components on the controlled mechanical properties: tensile strength and relative elongation. There are obtained regression models describing mechanical characteristics from the amount of aluminum, manganese, nickel and silicon directly related to the exploitation properties of the product. The applied bi-criteria approach makes it possible to determine of compositions ensuring relatively optimal values of the explored quality indicators.

  • MATHEMATICAL MODELLING OF TECHNOLOGICAL PROCESSES AND SYSTEMS

    THE PECULIARITIES OF THE METALLURGICAL DESIGN DEVELOPED THROUGH PROJECT MANAGEMENT PRINCIPLES

    • Tontchev N.
    • Dimitrov D.
    • Hai Hao
    Mathematical Modeling, Vol. 1 (2017), Issue 3, pg(s) 148-151
    • Abstract
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    •  Article PDF

    The tools for statistical expert evaluation of the influence of alloy composition elements on pre-selected quality indicators are described in order to improve the mechanical properties of the products through the prism of project management. Through the defined approach, it is possible to define a composition providing relatively best meanings of the values of the selected mechanical indices.

  • TECHNOLOGICAL BASIS OF “INDUSTRY 4.0”

    APPLICATION OF CAD DESIGN OF TECHNOLOGICAL PROCESSES IN THE FIELD OF MATERIAL SCIENCE

    • Yankov E. Hr.
    • Tontchev N.
    • Yonchev S.
    Industry 4.0, Vol. 2 (2017), Issue 6, pg(s) 249-252
    • Abstract
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    •  Article PDF

    A review of the existing methods applied to multi-criteria decision aiding has been made as well as the multi-criteria approach to a class of problems in the field of material science has been defined. The multi-criteria decision aiding has been successfully applied to determine appropriate compromise decisions about the examined parameters of a number of technological processes of welding, chemical thermal processing, iron covering, etc. The approach presented determines the values of technological factors satisfying the requirements of users simultaneously to a number of values examined and proposes a solution for the relatively highest thresholds at one and the same time

  • TECHNOLOGIES

    SELECTING THE OPTIMUM VARIANT OF THE SHEAR DRAWING PROCESS FOR LOW-CARBON STEEL

    • Tontchev N.
    • Semenov V. I.
    • Raab A. G.
    • Kamburov V.
    Machines. Technologies. Materials., Vol. 11 (2017), Issue 3, pg(s) 121-122
    • Abstract
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    •  Article PDF

    With the help of computer simulation in the DEFORM-3D software, there was performed a virtual full factorial experiment of the process of shear drawing. In the course of the experiment, the effect of independent parameters (drawing speed, die rotation rate, die angle and friction factor) on the strain intensity was evaluated. As a result of the experiment, a regression equation was derived and the most significant individual factors and their combinations, influencing the response parameters, were determined. Also, comparative results were presented for the processes of regular drawing and shear drawing. It was demonstrated that the process of shear drawing has a higher efficiency from the point of view of strain intensity.

  • COMPARATIVE ANALYSIS OF MODELS DSAT-16 AND MOTP_VTU TO CALCULATE THE PROPERTIES OF THE LAYER IN THE WELDING AREA

    • Hristova M.
    • Yankov E.
    • Tontchev N.
    Machines. Technologies. Materials., Vol. 10 (2016), Issue 6, pg(s) 21-24
    • Abstract
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    •  Article PDF

    The paper presents the characteristics of a modern software system for modeling and optimization of technological processes MOTP_VTU. It outlines the possibilities also to use the system at the design stage. A comparative analysis is performed of three characteristics to apply the new software system MOTP_VTU related to a similar existing one – DSAT-16. via similar systems it is possible to expand the basis of constructions and of functional materials in low technological level during exploration of the set of properties of these materials. This process of realization of scientific and technical ideas is a process to search via multi criteria support of decision making between the project task and the actual possibility, determined by the chemical composition and the processing-mode parameters.

  • COMPARATIVE ANALYSIS OF MODELS DSAT-16 AND MOTP_VTU TO CALCULATE THE PROPERTIES OF THE LAYER IN THE WELDING AREA

    • Hristova M.
    • Yankov E.
    • Tontchev N.
    Machines. Technologies. Materials., Vol. 10 (2016), Issue 4, pg(s) 10-13
    • Abstract
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    •  Article PDF

    The paper presents the characteristics of a modern software system for modeling and optimization of technological processes MOTP_VTU. It outlines the possibilities also to use the system at the design stage. A comparative analysis is performed of three characteristics to apply the new software system MOTP_VTU related to a similar existing one – DSAT-16. via similar systems it is possible to expand the basis of constructions and of functional materials in low technological level during exploration of the set of properties of these materials. This process of realization of scientific and technical ideas is a process to search via multi criteria support of decision making between the project task and the actual possibility, determined by the chemical composition and the processing-mode parameters.

  • MODELING AND OPTIMIZATION OF THE COMPOSITION OF TITANIUM -BASED ALLOYS BY APPROXIMATION WITH REGRESSION MODELS

    • Tontchev N.
    • Ivanov M.
    • Yankov E.
    Machines. Technologies. Materials., Vol. 10 (2016), Issue 1, pg(s) 23-25
    • Abstract
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    •  Article PDF

    The article is dedicated to an approach optimizing a task of statistical modeling of the mechanical properties of products in real production metallurgy design. The approach is designed for the benefit of producers-metallurgists aimed at providing panels of Ti – alloys of a specific set of eventual industrial properties. This is accomplished by a procedure of composition optimizing based on existing certificates of brands Ti – alloys. The article presents an approach using mathematical models of optimization problem following the implementation of approach the classical methodology capable of decision-making in the production practice.

  • ROBUST BI-CRITERIA APPROACH TO OPTIMIZE THE COMPOSITION AND PROPERTIES OF TITANIUM ALLOY

    • Tontchev N.
    • Kalev Y.
    Machines. Technologies. Materials., Vol. 8 (2014), Issue 12, pg(s) 26-30
    • Abstract
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    •  Article PDF

    The numerical experiment has proved the ability to improve the quality of titanium alloys. Mathematical models suitable for forecasting and optimization have been derived. The approach of Taguchi applied has lead to a desired result, to separate variables Xi for the examined parameters that do not influence significantly on the final result. With this limit, the numerical optimization for maximum search has been conducted with each chemical composition. That allows improving it.

  • SOFWARE MODEL FOR SELECTION OF THE APPROPRIATE CHEMICAL COMPOSITION OF TITANIUM ALLOYS UNDER DEFINES REQUIREMENTS FOR MECHANICAL CHARACTERISTICS

    • Ivanov M.
    • Tontchev N.
    Machines. Technologies. Materials., Vol. 8 (2014), Issue 11, pg(s) 27-30
    • Abstract
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    •  Article PDF

    The paper presents the application of modern computational approaches in determining the appropriate chemical composition of titanium alloys . Discusses three types of problems for the selection of the chemical composition of alloy at set requirements for mechanical properties . Tasks are solved in a different formulation of the target criteria . The proposed solutions are based on software model using approximation with artificial neural networks and genetic optimization algorithm.

  • INVESTIGATION OF MECHANICAL PROPERTIES OF TITANIUM ALLOYS BASED ON GENETIC OPTIMIZATION AND PARETO FRONT

    • Ivanov M.
    • Tontchev N.
    Machines. Technologies. Materials., Vol. 8 (2014), Issue 11, pg(s) 24-0
    • Abstract
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    •  Article PDF

    An approach to the study of the relationship between the extreme values of the mechanical properties of titanium alloys . The approach is based on the approximated dependence of the mechanical properties of the chemical composition of the alloy of the ANN model . Approximating dependencies are included in the genetic optimization model based on optimization algorithm NSGA II, which was built by Pareto – fronts , modeling the relationship between the studied mechanical parameters.

  • MODELING AND OPTIMIZATION OF THE PROPERTIES AND COMPOSITION OF TITANIUM-BASED ALLOYS

    • Tontchev N.
    • Kalev Y.
    • Lazarova R.
    Machines. Technologies. Materials., Vol. 8 (2014), Issue 11, pg(s) 16-19
    • Abstract
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    •  Article PDF

    The possibilities of regression analysis to model the properties and the related to it multicriteria optimization of the composition of titanium alloys are introduced in the presented research. This is done after performing characteristics of established applications of various titanium alloys. To predict elongation in this paper there have been obtained nonlinear regression models that allow to estimate the strength properties and the plasticity depending on the equivalents for aluminum and molybdenum for titanium alloys.

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