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Wyszukujesz frazę "Sokołowski, M.M." wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
Topological sensitivity analysis for a coupled nonlinear problem with an obstacle
Autorzy:
Abdelbari, M.
Nachi, K.
Sokolowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/205653.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
topological derivative
shape optimization
SteklovPoincaroperator
Signorini problem
variational inequality
Helmholtz equation
coupled partial differential equations
conical differential
asymptotic expansions
singular perturbations of geometrical Romains
truncated domain
Opis:
The Topological Derivative has been recognized as a powerful tool in obtaining the optimal topology for several kinds of engineering problems. This derivative provides the sensitivity of the cost functional for a boundary value problem for nucleation of a small hole or a small inclusion at a given point of the domain of integration. In this paper, we present a topological asymptotic analysis with respect to the size of singular domain perturbation for a coupled nonlinear PDEs system with an obstacle on the boundary. The domain decomposition method, referring to the SteklovPoincar´epseudo-differential operator, is employed for the asymptotic study of boundary value problem with respect to the size of singular domain perturbation. The method is based on the observation that the known expansion of the energy functional in the ring coincides with the expansion of the Steklov-Poincar´e operator on the boundary of the truncated domain with respekt to the small parameter, which measures the size of perturbation. In this way, the singular perturbation of the domain is reduced to the regular perturbation of the Steklov-Poincar´e map ping for the ring. The topological derivative for a tracking type shape functional is evaluated so as to obtain the useful formula for application in the numerical methods of shape and topology optimization.
Źródło:
Control and Cybernetics; 2017, 46, 1; 5-25
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On stability analysis in shape optimisation : critical shapes for Neumann problem
Autorzy:
Dambrine, M.
Sokolowski, J.
Żochowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/970525.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
optymalizacja kształtu
analiza stabilności
gradient kształtu
shape optimisation
stability analysis
shape gradient
shape Hessian
Opis:
The stability issue of critical shapes for shape optimization problems with the state function given by a solution to the Neumann problem for the Laplace equation is considered. To this end, the properties of the shape Hessian evaluated at critical shapes are analysed. First, it is proved that the stability cannot be expected for the model problem. Then, the new estimates for the shape Hessian are derived in order to overcome the classical two norms-discrepancy well know in control problems, Malanowski (2001). In the context of shape optimization, the situation is similar compared to control problems, actually, the shape Hessian can be coercive only in the norm strictly weaker with respect to the norm of the second order differentiability of the shape functional. In addition, it is shown that an appropriate regularization makes possible the stability of critical shapes.
Źródło:
Control and Cybernetics; 2003, 32, 3; 503-528
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Topological derivatives for semilinear elliptic equations
Autorzy:
Iguernane, M.
Nazarov, S. A.
Roche, J. R.
Sokolowski, J.
Szulc, K.
Powiązania:
https://bibliotekanauki.pl/articles/907655.pdf
Data publikacji:
2009
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
optymalizacja kształtu
pochodna topologiczna
nierówność wariacyjna
analiza asymptotyczna
shape optimization
topological derivative
level set method
variational inequality
asymptotic analysis
Opis:
The form of topological derivatives for an integral shape functional is derived for a class of semilinear elliptic equations. The convergence of finite element approximation for the topological derivatives is shown and the error estimates in the L [...] norm are obtained. The results of numerical experiments which confirm the theoretical convergence rate are presented.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2009, 19, 2; 191-205
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impact of modification with cetylpyridinium chloride – a potential cariogenic microflora inhibitor, on selected physical-mechanical properties of the water-activated glass-ionomer
Autorzy:
Kupka, T.
Nowak, J.
Szczesio, A.
Kopacz, K.
Fronczek-Wojciechowska, M.
Sokolowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/307009.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
twardość
wytrzymałość na rozciąganie
szkło
hardness
diametral tensile strength
glass-ionomer
Opis:
Teeth caries is one of predominant civilization diseases. Dental fillings with antimicrobial addition might allow prevention of secondary caries. The purpose of this study was to evaluate hardness and tensile strength of cetylpyridinium chloride modified water activated glass-ionomer cement. Methods: Samples with diameter of 6 mm and height of 3 mm made of water-activated glass-ionomer cement were control group (0.0%). Test groups were series of samples of the same dimensions, with addition of cetylpyridinium chloride antibacterial in concentrations of 0.5, 1.0, 1.5 and 2.0%. Two subgroups were prepared in each group to determine Vickers Hardness and Diametral Tensile Strength after 1 and 24 hours of sample storage in distilled water. Results: During hardness studies, no strong effect of antibacterial concentration on hardness of samples was observed. Higher hardness values after 24 hours were demonstrated for all groups, compared to the samples tested after 1 hour. The exception was the group with the addition of 1% cetylpyridinium chloride, in which no statistically significant differences were observed. Diametral Tensile Strength values for samples tested after 1 hour decreased with increasing antibacterial concentration. A similar relationship was noticed for samples tested after 24 hours. No statistically significant differences were found between test samples after 1 or 24 hours. Conclusions: There was no significant effect of cetylpyridinium chloride concentration on the hardness of the samples that significantly increased during the study. With the increase in antibacterial concentration a decrease in diametral tensile strength value was observed, but these values did not change over time.
Źródło:
Acta of Bioengineering and Biomechanics; 2018, 20, 3; 19-24
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
In-situ formed, ultrafine Al-Si composite materials: ductility
Autorzy:
Guba, P.
Gesing, A.
Sokolowski, J.
Conle, A.
Sobiesiak, A.
Das, S.
Kasprzak, M.
Powiązania:
https://bibliotekanauki.pl/articles/366887.pdf
Data publikacji:
2019
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
ultrafine Al-Si composite
Al metal matrix
hypereutectic Al alloys
mechanical properties
high ductility
osnowa metalowa
stop nadeutektyczny
właściwości mechaniczne
ciągliwość
Opis:
Purpose: The work objective includes optimization of the casting production and heat treatment processes that will simultaneously maximize the combination of strength, hardness, and ductility for hypereutectic Al-Si compositions with Si volume fractions of as much as 25 vol.%. In addition, such an in-situ formed composite alloy will attain a unique combination of low production cost, high potential recycled content, and functional characteristics suitable for mission critical aerospace and vehicular applications. Design/methodology/approach: The unique High Pressure Die Casting Universal Metallurgical Simulator and Analyser (HPDC UMSA) was used for melting, cyclic melt treatment, and solidification of the hypereutectic Al-Si-X (A390). The produced as-cast structures contained colonies of nano-diameter Si whiskers and other morphologies, and absence of primary silicon particles. Heat treated structures rendered nano and ultrafine metal matrix composites. Findings: New developed as-cast Al-Si materials containing nano-diameter Si whiskers, without primary silicon particles required ultra short time heat treatment to result in nano and ultrafine metal matrix composite, rendering their hardness, strength and wear resistance, and the same time retaining toughness and ductility. Research limitations/implications: The cast samples were produced in laboratory conditions and potential tensile strength was estimated from empirical correlation with micro-hardness measurements. In the future, the comprehensive mechanical properties need to be tested. Practical implications: These ultrafine Si, Al-MMCs can be net-shape formed by modified HPDC technology or consolidated from spray-atomized alloy powder. Originality/value: Optimization of the entire production process for the hypereutectic Al-Si alloy compositions achieved a uniform distribution of ~ 25 vol.% of ultrafine Si particles in ductile FCC-Al matrix further reinforced by age hardening with nano-scale spinodal GP-zones. The associated mechanical property and ductility improvements will open a wide range of critical lightweighting components in transportation: aerospace, terrestrial vehicle and marine to the optimized hypereutectic Al-Si alloys. Presently, these components do not use the commercial HPDC A390 alloys due to their limited ductility and strength. Proposed new technology will allow conversion of various cast airspace alloys with ultrahigh mechanical properties to the automotive applications.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2019, 92, 1-2; 5-12
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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