Unified microporomechanical approach for mechanical behavior and permeability of misaligned unidirectional fiber reinforcement

The microporomechanical approach (via homogenization schemes) has been used and combined with triaxial tests to verify the Biot theory for the perfectly straight unidirectional fiber assembly in a previous paper [Tran T, Binetruy C, Comas-Cardona S, Abriak NE. Microporomechanical behaviour of perfectly straight unidirectional fiber material: theoretical and experimental. Compos Sci Technol 2009;69:199–206.]. The comparison of theoretical and experimental results is in good agreement, i.e. the Biot coefficients are clearly lower than one for densely packed fiber array. This result will be developed in this article in the case where the fibers are not perfectly straight but in misalignment (unidirectional fiber assembly in localized contact). Furthermore, within the same theoretical framework, the transverse compression modulus and the hydraulic permeability will be also estimated for the fiber reinforcement of double-scale porosity. The homogenization schemes used in this article are the self-consistent and the one proposed by Mori–Tanaka. The estimated and, when possible, bibliographical results for different types of fibrous materials (carbon, kevlar and glass fibers) are compared and show good agreement.