SMART STRUCTURES APPROACH: ACHIEVING GLOBAL STRUCTURAL HEALTH MONITORING THROUGH THE APPLICATION OF DISTRIBUTED, EMBEDDED MICRO-SENSOR SYSTEMS

Multi-site fatigue damage, hidden cracks in hard-to-reach locations, disbonded joints, erosion, impact, and corrosion are among the major flaws encountered in today's extensive array of aerospace vehicles and civil structures. These damage scenarios, coupled with new and unexpected phenomena, have placed greater demands on the application of advanced nondestructive inspection (NDI) and health monitoring techniques. Reliable, structural health monitoring systems can automatically process real-time data, assess structural condition, and signal the need for human intervention. Prevention of unexpected flaw growth and structural failure could be improved if on-board health monitoring systems are used to continuously assess structural integrity. Such systems would be able to detect incipient damage before catastrophic failures occurs. Condition-based maintenance practices could be substituted for the current time-based maintenance approach. Other advantages of on-board distributed sensor systems are that they can eliminate costly, and potentially damaging, disassembly, improve sensitivity by producing optimum placement of sensors with minimized human factors concerns in deployment, and decrease maintenance costs by eliminating more time-consuming manual inspections. This chapter focuses on developments in mountable sensors and how they can be integrated into such a Structural Health Monitoring (SHM) system to guide condition-based maintenance activities.