Real-Time Inspection of Fasteners in Aerospace Structures

As military aircraft limits are continuously extended, there is an equivalent need to develop improved and more effective non-destructive evaluation (NDE) techniques for detection of flaws. This especially applies to the development of NDE techniques,which are capable of rapidly detect and visualize flaws, defects and discontinuities in aircraft fasteners.TPL has been developing a new NDE technology based on giant magnetoresistive (GMR) sensors. Such sensors are ultrasensitive to magnetic fields and are highly effective in locating defects and quantifying their magnitude. Sensor arrays can be established onhandheld devices for a rapid and accurate detection and visualization of hidden flaws in fasteners.In Phase I a prototype GMR based NDE imaging system will be developed. To prove the feasibility of the system, it will be used to scan a sample surface with irregularities (steps), mimicking the aircraft fastener-skin interface. The resolution and thescanning time will be assessed and compared with the ones prescribed by the Navy.TPL is a leader in the development of GMR-NDE technology. The principal investigator has extensive experience in magnetic field sensors. The major commercial benefit of the GMR based NDE imaging system proposed will be the development of a technology for rapid detection of flaws in conductive materials with non-uniform surfaces. This applies especially to commercial aircraft NDEtechniques for non-destructive detection and imaging of flaws, defects and discontinuities in fasteners and similar parts and surfaces.This technology could also be successfully used for flaws detection and imaging of various industrial equipment containing flanges. Such an example would be industrial reaction vessels under pressure.