Development of Smart High Strength Bolt Systems with Health Monitoring Capability

Our ultimate goal is to develop, manufacture and verify a smart high strength bolt system which offers health monitoring capability and eliminates the need for periodic removal and nondestructive evaluation of bolts. Phase I research will identify a system design for smart high strength bolts, and will select the structural and health monitoring components as well as the inspection scheme for this system in order to satisfy the structural, health monitoring and processing requirements compatible with the existing MS 21250 specification. The alternative system design to be considered include: (1) a monolithic smart/structural system; (2) tagging smart particles dispersed into a structural host matrix; (3) smart fibers inserted into a structural host matrix; and (4) structural material with a smart coating. Some key smart materials to be investigated for incorporation into these system designs include: shape memory, electrostrictive, piezoelectric, magnetostrictive, electroresistive, and fiber optic materials. Steel as well as metal matrix composites are examples of structural materials for the smart bolt system. Both passive and active health monitoring schemes will be considered. Phase I research comprises the following tasks: (1) survey the available smart technologies and assess their applicability to different system designs for active or passive health monitoring; (2) select the best system design and its structural and health monitoring components; (3) identify signal detection and interpretations schemes for health monitoring; (4) determine the economic viability of the selected smart bolt systems; and (5) prepare the final report. Phase II research would physically manufacture and verify the smart bolt system, would refine and finalize the design and deliver a level III drawing package.