Fibrous composite with threshold strengths in multiple directions: Design and fabrication

This work reports the design of a composite consisting of square fibers separated by thin compressive layers. Fracture mechanics analysis indicated that this composite showed radial and axial threshold strengths corresponding to applied stresses in the direction perpendicular to the fiber side face and parallel to the fiber central axis, respectively. In accordance with the above designing concept, Si3N4/TiN fibrous composites with distinctive threshold strengths were prepared through a simple double-laminating procedure. The measured radial threshold strength of the Si3N4/TiN composite agreed quite well with the theoretical prediction, while a substantial discrepancy existed between the measured and predicted axial threshold strength due to the difference in the configuration of the cracks used in testing and theoretical modeling of the axial threshold strength.