ASSESSMENT OF THE INTERFACIAL PROPERTIES OF CERAMIC-MATRIX COMPOSITESUSING STRAIN PARTITION UNDER LOAD

The interfacial sliding stress is a key parameter in the global behavi or of ceramic-matrix composites. An ultrasonic characterization, throu gh the complete determination of the stiffness tensor along a tensile test, detects all the damage mechanisms: transverse matrix microcracki ng and the existence of longitudinal cracks at the fiber/matrix interf ace. It also allows a strain partition under load. A micromechanical m odel is established and gives access to the value of the interfacial s liding stress during the entire tensile test, whether the damage occur s at the mesostructural or at the microstructural level of the composi te.