Discrete failure mode detection in a woven SiC cloth reinforced glass composite

Abstract

Single layer silicon carbide cloth reinforced glass composites were fabricated and subjected to three-point bending in order to develop better models of failure mechanisms. Acoustic emission (AE) monitoring was also performed during the bend tests to help isolate these mechanisms. During the basic flexural tests, discrete failure modes, which were often not visible from specimen surfaces, displayed their existence through characteristic load-deflection curve unloading regions and abrupt changes in acoustic activity. Microscopic three-point bend tests were then performed to elaborate on the results of the conventional bend tests. Observations made during the microscopic bend tests provided a one-to-one correlation with load-deflection curve anomalies and acoustic emission activity. As a result of the different mechanical, optical and acoustical techniques used, discrete failure mechanisms for the cloth reinforced ceramic matrix composite (CMC) were conclusively established.