Novel process for monitoring stress in carbon fiber reinforced polymer composites using magnetostrictive wires from cryogenic to high temperatures

Abstract

Carbon-fiber-reinforced polymer (CFRP) is widely used in aerospace owing to its high strength, high elasticity, and low density. Recently, CFRP has been used at different temperatures, such as severe temperature environments near aircraft engines and cryogenic fuel tanks. Structural health monitoring (SHM) is needed to ensure the safe use of such structural components. Magnetostrictive materials are desirable candidates for SHM sensors owing to their ability to interconvert mechanical and magnetic energies and their excellent features, such as wide operating temperature range, long life, and low cost. In this study, iron–cobalt (Fe–Co) wires were embedded in CFRP composites (Fe-Co wire/CFRP composites), and their magnetic and magnetostrictive properties were evaluated. The magnetostriction was also analyzed using the nonlinear constitutive equation for magnetostrictive materials. Further, microstructural analysis was conducted, and the effect of microstructure on the magnetostriction of the specimens was analyzed. Finally, a four-point bending test was performed on the Fe–Co wire/CFRP composites at different temperatures, and the change in magnetic flux density with stress was measured. The obtained results serve as a reference for developing high-performance Fe–Co wire/CFRP composites for SHM sensors operating at high and cryogenic temperatures.