Lw. Anson et al., ON THE FEASIBILITY OF DETECTING PRE-CRACKING FATIGUE DAMAGE IN METAL-MATRIX COMPOSITES BY ULTRASONIC TECHNIQUES, Composites science and technology, 55(1), 1995, pp. 63-73
The feasibility of using ultrasonic techniques to defect fatigue damag
e in metal-matrix composites at an early stage has been investigated t
heoretically. The lack of direct independent experimental evidence for
such damage required damage mechanisms and levels to be postulated in
a somewhat arbitrary fashion. Estimates have been made of the effect
of matrix porosity, microcrack formation, particle debonding and dislo
cation generation on ultrasonic velocity, attenuation and backscatteri
ng. It would seem that velocity measurements provide the best opportun
ity for detecting low levels of damage. Initial calculations suggest t
hat surface wave velocity measurements and acoustoelastic constant mea
surements may also prove useful.