Investigation of Terfenol-D for Magnetostrictive Tagging of Fiber-Reinforced Polymer Composites

The U.S. Army maintains an aging inventory of over 143,000 buildings representing 54.6 billion in high priority, unfinanced maintenance and repair. Many of these structures fail to meet modern building codes and require structural upgrades. The objective of this research was to develop a cost-effective magnetostrictive fiber-reinforced polymer (FRP) composite material that can be fabricated into structural elements capable of generating data about their own structural condition, and which can be monitored and assessed by measuring its electromagnetic flux over time. The magnetrostrictive material selected for these tagging experiments was terfenol-D. The studies documented in this report address theoretical and applied aspects of tagging FRP composites with magnetostrictive particles to enable the monitoring of loads, strains, and damage in structural members using portable, readily available nondestructive monitoring equipment. After theoretical models were developed, various types of magnetostrictive-tagged resin matrices - both unreinforced and glass-fiber reinforced were designed, fabricated, tested, and analyzed in laboratory experiments. Taken collectively, the results of these studies indicate that magnetostrictive-tagged composites have great potential for application in self-monitoring structural technologies in the field.