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Statistical optimization of stress relieving parameters on closed cell aluminium foam using central composite design

Puspitasari D., Ginta T. L., Mustapha M., Sallih A., Puspitasari P.

Archives of Materials Science and Engineering

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2018

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Vol. 89, nr 2

55--63

EN

Purpose: This study concerns about the influence of stress relieving parameters on the hardness of closed cell aluminium foam using central composite design. Design/methodology/approach: The responses of three stress relieving parameters: heating temperature, holding time and stabilization temperature are studied and analysed through 20 experimental runs designed according to central composite design. The results of microhardness test corresponded to the microstructural evaluation of closed-cell aluminium foam using optical microscope. Analysis of Variance (ANOVA) technique is employed to study the significance of each parameter on the microhardness property. In this process the design has five levels for each parameter. The stress relieving process of the samples were performed using a vacuum furnace. The hardness test was conducted using a micro hardness tester LM247AT and the microstructure of the samples were obtained using optical microscopy technique. Findings: It was found that the highest value of hardness of 192.78 HV was obtained when the stress relieving process is set with the following parameters: heating (500°C); holding time (120 min) and stabilization temperature (450°C). Since higher heating temperature and longer holding time produce sample with larger grain size and has an adverse effect on the hardness value. Research limitations/implications: Liquid metal and powder metallurgical processing still produces a non-uniform and poorly reproducible cellular structure. This cellular structure demonstrates poor quality difference on decomposition and melting temperature, called anisotropic early expansion. Originality/value: To improve the poor cellular structure quality, stress relieving method is proposed in this study. Stress relieving method can improve the microstructure of the material.

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Betony wysokowartościowe - kryteria optymalizacji składu

Prokopski G., Franczyk M.

Budownictwo Ogólne i Konstrukcje Drewniane : zeszyt naukowy

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2008

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Nr 9

61--71

PL

W pracy przedstawiono zasady projektowania składu, a także efekty zastosowania wielokryterialnej optymalizacji statystycznej w analizie wyników badań betonów wysokowartościowych (BWW). Analizę i ocenę badań przeprowadzono w obszarze przyjętego planu doświadczeń. Efektem działań było uzyskanie rozwiązań preferowanych w zakresie składu betonów z uwagi na przyjęte kryteria optymalizacji.

EN

This paper presents the effect of use the mathematics methods optimization to design High Performance Concretes. The analyses and valuation of concretes property have realized in the plan experiences on the basis of 6 criteria optimization. The results of analyses have presented as the preferred solutions of concretes composition.

3

Komputerowe wspomaganie zarządzania eksploatacją systemów technicznych przy zastosowaniu symulacji cyfrowej. Cz. III.

Kołodziński E.

Zagadnienia Eksploatacji Maszyn

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2002

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Vol. 37, nr 4

123-137

PL

W części pierwszej artykułu scharakteryzowano symulacyjną metodę badania systemów, zwracając uwagę na to, że praktyczne jej stosowanie uwarunkowane jest adekwatnością modelu. Rozpatrywano adekwatność modelu symulacyjnego. W niniejszej części rozpatrzono zagadnienie wyznaczania charakterystyk działania systemu jako najczęściej spotykane w praktycznym zastosowaniu symulacyjnej metody badania systemów. Zadanie wyznaczania charakterystyk tą metodą sprowadzono do określenia modelu matematycznego regresji pierwszego rodzaju. Podano i pokrótce scharakteryzowano etapy wyznaczania regresji jako charakterystyki działania systemu przy zastosowaniu symulacji cyfrowej. Zasygnalizowano również możliwości optymalizacji statystycznej na podstawie modelu regresji wyznaczonego symulacyjnie.

EN

The aim of the simulation research described in the first part of paper is to calculate the characteristics, the degree of influence on their course of determined factors or to solve optimisation tasks: the calculation of optimum control, optimum structure and so forth. The characteristics of the system functioning are interpreted as expected conditional values of certain quantities of relative factors - independent variables. The characteristics and the solution of optimisation tasks are calculated on the ground of the observation of the simulation model of the system being examined i.e. on the ground of its mathematical model. The consistency of the solution or the characteristics with their real values depends, among other things (sometimes, first of all), one the adequacy of the simulation model of the system being under observation to the processes occured in it. In the most general way, the adequacy valuation consists in the finding of the decision rule which, on the ground of the results, of the experiments carried out in the examined system and the realisation of the simulation model, allows to state that: - There is no ground to reject the hypothesis concerning the process carried out in the examined system or; - The obtained results deny the truthfulness of the hypothesis concerning the simulation model adequacy. The methods of the construction of such decision rules, mathematical apparatus and the methods of the settlement of the problems of the simulation model adequacy are the subject of the consideration of the present paper. In the paper the problem of the statistical valuation of the simulation model adequacy has been formulated, the procedure of the adequacy valuation on the ground of the retrospective predication of the processes occurred in the examined system has been presented and the tests particularly useful for application have been shown.

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Wielokryterialna optymalizacja statystyczna betonów wysokowartościowych

Franczyk M., Konkol J.

Przegląd Budowlany

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2001

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R. 72, nr 11

9-14