The inverse problem in the reinforcement theory of fibre-reinforced composites

The inverse problem in Wilczyńskiʹs reinforcement theory of fibre-reinforced composites (Wilczyński AP. A basic theory of reinforcement for unidirectional fibrous composites. Comp Sci Technol, 1990;38:327–337; Wilczyński AP, Lewiński J. Predicting the properties of unidirectional fibrous composites with monotropic reinforcement. Comp Sci Technol, 1995;55:139–143) has been solved fully analytically. This problem is understood as determination of the elastic constants of monotropic fibres, having the elastic constants of the isotropic matrix and the elastic constants of the homogenised monotropic composite material, measured experimentally. The analytical solution of the inverse problem has been computerised and positively tested, for both theoretical and experimental data related to the selected polyethylene/epoxy composite.