Early fatigue damage detecting sensors—A review and prospects

• Eight types of fatigue damage sensors are introduced and discussed.
• A novel concept of fatigue monitoring sensor utilizing carbon films is proposed.
• Me-DLC films are good candidate materials for fatigue monitoring sensors.

Fatigue damage detection and fatigue life prediction are important technological issues in both academic and industrial fields. Numerous techniques have been proposed and developed for the detection of early fatigue damage in structural members. This paper provides a brief review of the current state-of-the-art on fatigue damage sensors. Eight types of existing fatigue damage sensors based on different detecting principles are introduced and discussed, with the emphasize on the two commercially available fatigue damage sensors, the fatigue fuse with a slit and the electrical resistance fatigue gauge. Moreover, a novel concept of utilizing carbon films as a fatigue monitoring sensor is proposed. The preliminary experimental results suggest that metal-containing diamond-like carbon (Me-DLC) films with optimum composition and micro-structure will be good candidate materials for fatigue monitoring sensors.