ELASTIC BEHAVIOR OF MULTIPLY COATED FIBER-REINFORCED COMPOSITES

This work is devoted to the derivation of the elastic strain and stres s fields in an infinite medium constituted of an n-layered transversel y isotropic cylindrical inclusion, surrounded by a transversely isotro pic cylindrical matrix subjected to uniform conditions at infinity. Fr om these results, the average strain and stress are calculated in each phase and in the n-layered inclusion. These averages are used in orde r to estimate the overall elastic moduli of heterogeneous fibre-reinfo rced materials. Christensen and Lo's energy condition for the three-ph ase model is extended to this case and shown to be equivalent to a str ain (or a stress) condition. Whereas the method yields a new estimate for the transverse shear modulus, the four other moduli are proved to be given by the coincident Hashin-Rosen bounds for the n-C.C.A. and ca n be derived by a recursive algorithm.