Acoustic emission and damage evolution in an SiC fiber reinforced Ti alloy composite : 58998 Takashima, K.; Tonda, H.; Bowen, P. Journal of Acoustic Emission, Vol. 13, No. 1–2, pp. S8–S13 (Jan.–Jun. 1995)

Abstract

Damage evolution in an SiC fiber reinforced Ti alloy composite (SCS-6/Ti-6Al-4V) has been assessed by acoustic emission (AE), stiffness loss and internal friction (mechanical damping). Damage in the composite was introduced by four point bending through both a series of stepwise monotonic loading and unloading sequences, and cyclic loading. AE signals were monitored during the tests, and Young's modulus and internal friction were measured by a flexural resonant method. In both stepwise loading and cyclic loading, the Young's modulus decreased by only 1% before failure of the specimen. However, the internal friction began to increase gradually after loading, and increased rapidly prior to failure in both types of tests. Cumulative AE energy increased with increasing internal friction in both types of tests. These results suggest that the evolution of damage in such composites can be assessed by a combination of AE monitoring and internal friction measurements.