Browsing by Subject "parametry efektywne"

Now showing 1 - 2 of 2

Access status: Open Access ,
Numeryczne określanie parametrów efektywnych transportu na podstawie cyfrowych obrazów mikrostruktury
(Wydawnictwa AGH, 2010) Różański, Adrian; Łydżba, Dariusz; Sobótka, Maciej
In this work computationally efficient method of effective transport properties determination is proposed. The methodology is applied to digital images of random microstructures. It is shown that effective properties can be evaluated as mean values averaged over sufficient number of samples. The sample is assumed to be a finite-sized region which is a part of digital image. The condition regarding sample size, based on the variance of local volume fraction, is proposed. The variance is shown to be calculated on the basis of two-point probability function. Sample size criterion is verified for two different digital images of random microstructures.
Access status: Open Access ,
Uwagi o wielkości reprezentatywnej elementarnej objętości dla losowych mikrostruktur komórkowych
(Wydawnictwa AGH, 2009) Różański, Adrian; Łydżba, Dariusz
The aim of this work is to propose a more quantitative definition of representative volume element (RVE), i.e. by defining both the size of the sample and the sufficient number of realizations. The methodology is applied to a specific random microstructure, namely two-phase two-dimensional square lattice model. It is shown that the geometrical property, namely volume fraction, can be determined either for large samples and a small number of realizations a smaller volumes can be utilised providing that a sufficient number of realizations are considered. It is proved analytically that in case of transport properties there exist some threshold value of the size of RVE below which the results do not converge towards effective properties. This size of the sample is determined by making use of the properties of the two-point probability function.