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Methodology of Optimum Selection of Material and Semi-Folded Products for Rotors of Open-End Spinning Machine

Płonka Stanisław, Postrożny Jacek, Drobina Robert

Autex Research Journal

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2021

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Vol. 21, no. 4

393--402

EN

The article presents the methodology of optimal selection of material and the form of semi-product for the rotors of the spindle-less spinning machine. The multicriteria approach was utilized taking into account versatile criteria. The applied procedure consists of two stages: the optimum method in the Pareto sense and the method of distance function. Based on the analysis of the spinning head work, rotor and availability function, six different materials and three forms of semifinished products (extruded bar, forged element, and cast element) were considered. In consequence, the admissible set consisting of nine elements was obtained. For the evaluation of technological quality of the rotor, the following criteria were proposed: index of functionality of the material σf/ρ, maximum height of the surface peaks, Sp, and maximal hardness on surface of oxide layer μHV0,1. Finally, taking into account the economical criterion (unit cost), the Pareto-optimal set of solutions was determined based on four criteria. Due to the fact that this set contained five variants, the distance function was utilized for choosing the best final variant. The optimal material and the semi-product (because of the assumed criteria) chosen were as follows: alloy AlSi1MgMn and the forged element - because in this case the value of distance function was minimal.

2

Multicriteria optimization of sandwich cylindrical panels under axial compressive loads

Kasperska R., Ostwald M.

Journal of Theoretical and Applied Mechanics

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2002

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Vol. 40 nr 2

371-388

EN

The aim of this paper is to present the bicriteria optimization model of a sandwich cylindrical panel under axial compression. The objective functions are the weight and panel deformability. The deformability is defined as the panel bending rigidity reciprocal, and it represents some qualitative measure of the panel deflections. the design variables are the thicknesses of the layers. The constrains include a stability condition, stress conditions, the validation of theoretical models, and finally, technological and constructional requirements. The problem was solved with the help of Pareto's concept of optimality, with continuous and discrete sets of the design variables. Results of numerical calculations are presented in the form of tables and diagrams. A comparison of the optimal parameters for the unilayer and the sandwich panels is presented.

PL

W pracy sformułowano model dwukryterialnej optymalizacji cienkościennej trójwarstwowej paneli walcowej obciążonej osiowymi siłami ściskającymi. Kryteriami optymalizacyjnymi są masa paneli i jej podatność na odkształcenia. Podatność paneli, zdefiniowana jako odwrotność sztywności na zginanie, jest jakościową miarą odkszałcalności konstrukcji. Zmiennymi decyzyjnymi są grubości warstw paneli. Warunkami ograniczającymi są warunek stateczności, warunki wytrzymałościowe, warunek ważności stosowanych modeli teoretycznych oraz warunki technologiczno-konstrukcyjne. Zadanie rozwiązano w oparciu o koncepcję optimum Pareto, uwzględniając dyskretne i ciągłe zbiory zmiennych decyzyjnych. Wyniki obliczeń numerycznych przedstawione są w postaci tabel i wykresów. Porównano optymalne parametry paneli jedno- i trójwarstwowych.

3

Critical points for vector-valued functions

Lucchetti R., Revalski J., Thera M.

Control and Cybernetics

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2002

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Vol. 31, no 3

545-555

EN

This paper contains a mountain pass theorem for continuous mappings, defined on a complete metric space and taking values in a real Banach space, ordered by a closed convex cone. We use the concept of critical point introduced by Degiovanni, Lucchetti and Ribarska, and we furnish a variant of their result, allowing for a localization both of the critical point and of the critical value.