Effective transverse elastic moduli of a composite reinforced with multilayered hollow-cored fibers

The transverse elastic moduli of a unidirectional composite material reinforced with identical multilayered hollow-cored fibers are evaluated by the use of a multiphase generalized self-consistent model, on the basis of a previously established plane-elasticity solution to the problem of a multilayered hollow-cored circular inclusion under uniform remote stresses. The analysis leads to a pair of algebraic equations, which can easily be numerically inverted. Numerical examples for composites reinforced with thinly-coated hollow-cored fibers, and with osteon-like fibers (modelling cortical bone tissue), are presented. In particular, it is found that the effective transverse Poisson ratio becomes negative beyond certain porosity levels, and that the parity of the number of fiber layers is a significant parameter.