Structural health monitoring (SHM) technologies

Uses a wing box with aluminum spars and ribs that is manufactured with interchangeable metallic spars, and metallic and composite skins. Specific procedures are developed by the NRC SHM team to grow hidden cracks emanating from holes, or sections of the skins, spars and ribs. The structure can be fatigue-loaded using a realistic aerospace spectrum. The test facility in Ottawa enables collaborators to place their SHM systems on NRC SHM testing platforms to determine the system's capabilities and reliability for identifying and quantifying damage locations in increasingly complex aerospace structures. The test facility in Boucherville has developed Integrated Ultrasonic Transducers (IUT) for SHM or predictive maintenance. The advantages of the IUT include: no coupling material is needed for ultrasounds, they can be performed at high temperatures, they are self-damping, offer a broadband and center frequency range of 2 – 20+ MHz and can perform conformal mapping on complex geometries and mechanical flexibility.

Evaluates load-monitoring system capabilities using an eighteen foot simple cantilever aluminum beam to measure bending, torsion and shear loads. The load-monitoring platforms are well characterized and documented, providing realistic test conditions encountered during the service life of aerospace structures.

Uses instrumented research aircraft and actual aircraft structures, such as a wing of a CF188 fighter aircraft or a tail boom of a helicopter. This platform contains the most challenging realistic case scenario and requires the SHM and load monitoring systems to be of a higher technology readiness level (TRL) to identify the realistic loads and damages that can occur in this aerospace structure.

Developed by NRC, the Surface Mountable Crack Detection System (SMCDS), uses a paint-on sensor to detect damage on small- and large-scale airframe structures. The conductive nature of the SMCDS allows for the system to be interrogated using low voltage signals and minimal power either during or after completion of the flight. An installation kit has been manufactured that contains the instructions and the materials required for the installation and operation of this sensor suite.

NRC has access to Acellent Inc.'s Ultrasound SHM system, which consists of a network of piezoelectric actuators and sensors and uses multiple diagnostic wave types that can be generated for real-time visualization of structural changes.

NRC has been integrating SHM sensors with wireless transmitters, while developing custom software and algorithms to monitor damage and loads. Sensors include strain gauges, displacement transducers, piezoelectrics, MEMS, fibre optic sensors, temperature sensors and others.