Self-Sensing Health of Carbon Composite Pultrusion Strength Members

Abstract

In applications such as race boat rigging, offshore umbilicals and energy kite tethers which require light weight and high stiffness strength members, there is no better material choice than carbon composite pultrusion. However, designing an optimized termination profile for fatigue driven applications is time consuming and generating stress versus cycle to failure (S-N) curves is expensive. Fortunately, owing to electrical properties inherent in carbon pultrusions, self-sensing techniques can be correlated to microscopic damage to provide useful new metrics on which to base design specifications. This paper presents a new technique for self-sensing health via 4-wire method of carbon composite pultrusion materials in gauge and termination region of a full-scale system. This self-sensing method sheds light into system stress state and permits measurement of damage from crack propagation due to fatigue using robust and widely available tools. These self-sensing signals have clear potential utility for speeding design tasks, defining lifetime ratings and providing real-time system diagnostics of high performance strength members