Real-time monitoring of fatigue damage and dynamic strain in a continuous unidirectional carbon fiber polymer-matrix composite by longitudinal electrical resistance measurement was achieved. The resistance R decreased reversibly upon tensile loading in every cycle, thus providing dynamic strain monitoring. The peak R in a cycle irreversibly increased as fatigue damage occurred, due to fiber breakage. At 55% of the fatigue life, the peak R started to increase in spurts. At 89% of the fatigue life, the peak R started to increase continuously from cycle to cycle, but gradually. At 99.9% of the fatigue life, the peak R started to increase rapidly, both continuously and in spurts. The last spurt occurred at 99.997% of the fatigue life.

Date Published: 9 February 1996
PDF: 8 pages
Proc. SPIE 2716, Smart Structures and Materials 1996: Smart Materials Technologies and Biomimetics, (9 February 1996); doi: 10.1117/12.232147

Published in SPIE Proceedings Vol. 2716:
Smart Structures and Materials 1996: Smart Materials Technologies and Biomimetics
Andrew Crowson, Editor(s)