Fastener Hole ET, Including Holes with Nut Plates

Phase I will develop prototypes for two bolt hole probes, using innovative linear drive eddy current array formats (similar to the JENTEK MWM-Array). The first probe will be designed to operate with the NEW moderately priced GridStation (the GS-Durable a soon-to-be-introduced JENTEK instrument provided in 7-, 15- or 37-channel versions) for bolt-hole C-Scan imaging, providing inspection of the entire internal hole surface for holes with and without nut plates. The second probe will include two pairs of channels that can operate in differential or absolute mode and work with either the NEW low cost GS-Hand-Held (a soon-to-be-introduced two-channel JENTEK instrument) or conventional ET instruments currently used by the Air Force. This SBIR will not only deliver a new practical probe for bolt-hole inspections with nut plates that can be used with either JENTEK or competitive Nondestructive Testing instruments; but also deliver enhanced C-Scan imaging capability for bolt holes that will provide substantial advantages over current practice at an affordable price. This will include POD curve generation in Phase II for cracks at edges at the nut plate end and for cracks in other locations for direct performance comparisons. BENEFIT: If this program is successful, the Air Force will have two advanced bolt hole inspection probes: one that will deliver superior inspection performance in all areas of bolt holes, including at the end of the hole near a nut plate, using JENTEK GridStation instruments; and a second probe that will work with competitive instruments to support inspection of bolt holes with nut plates. This will provide the Air Force with a clear choice for nondestructive testing solutions for bolt holes.