Reliability assessment of different SHM and load monitoring systems under load and environmental conditions

摘要

As part of an experimental program to assess and validate different Structural Health Monitoring (SHM) systems, the National Research Council Canada (NRC) has been developing several SHM test platforms ranging from a simple cantilever beam to a full-scale CF-18 fighter aircraft wing. In this ongoing study, a wingbox structure similar to the complexity of the inner structures found in the CF-18 outer wing, with fastened ribs, spars and skins was used to create representative in-service hidden fatigue crack of specific size and location. The hidden crack was grown using bending loads under room, hot/wet, and cold/dry environments to evaluate different SHM systems' abilities to detect such damage and to monitor its growth under simulated service conditions. Four different SHM techniques were evaluated, which include: Acoustic Emission, Acouto-Ultrasonics, fiber optic strain sensor, and a NRC developed Crack Indication Sensor (KIS). The ability of each sensor technology to survive in realistic environmental conditions and the effect of these environmental conditions on the sensor signal were assessed.