Smart-Materials-Based Struct ural Health Monitoring Systems Development for Aerospace Applications

摘要

A description of a recently develoepd structural health monitoring technology is provided. The approach is based on a strain-dependent, solid-state, martensitic phase transformation that occurs in some metastable iron-base alloys. Sensor elements are positioned within a structure to provide an indication of mechanical straining which would accompany engineering component degradation. The sensors then provide local compliance information about critical, highly-stressed structural locations. The increase in structural compliance associated with component degradation can be detected and monitored during the gradual accumulation of damage during service. Since the methodology is based on an irreversible martensitic phase transformation, the sensors can operate passively to provide peak strain information when interrogated or actively to provide peak strain history and/or to trigger alarms or other secondary safety systems in the event that the local straining reachjes a predetermined level of concern. A crack detection and monitoring system developed for the tang region of the C-130 cargo aircraft wing truss assembly is discussed. Also, the development of smart aircraft bolts for critical structural locations is discussed. Test data and a discussion of the application of these systems are presented.