Radial matrix cracking and interphase failure in transversely loaded fiber composites

Radial matrix cracking and interphase failure for transverse loading of a hexagonal array fiber composite are investigated by: (1) modeling the interphase by a layer of radial and circumferential spring elements, (2) adopting a tensile stress criterion for initiation of matrix cracking, and (3) employing a strain-energy density criterion for interphase failure. The mechanical behavior of the composite is defined in terms of geometrical, stiffness and strength parameters. Stresses on the microlevel have been calculated. Under the assumption that the failure mechanisms follow the periodicity of the composite, two scenarios related to different values of the strength parameters have been investigated. In the first scenario matrix cracking occurs first, followed by interphase failure. In the second scenario interphase failure is followed by matrix cracking. Typical results are displayed graphically.