To calculate the effective moduli of periodic composites and porous media for the case when the ratio of the inhomogeneity scale and the global length scale of the process is small, there is a well-known algorithm which is based on the method of two- scale asymptotic expansions. In this paper media and processes are considered which are characterized by additional small parameters, namely materials with a stretched structure as well as materials with pores or inclusions having shapes of parallelepipeds or rectangular channels at certain conditions on the values of matrix and inclusions moduli and volume concentration of inclusions. Generalization of the classic algorithm for such structures is proposed and calculations are performed. The dependencies of the values of the effective moduli on the degree of the structure stretching, geometrical shape of the inclusions, the ratio of the inclusion and the matrix moduli and on the inclusions (pores) volume concentration are studied. Comparison of the calculated effective coefficients values with the values obtained by explicit approximate formulae derived earlier is given.
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