UH-60 BIM Blanket Tap Test Evaluation
Abstract
Corpus Christi Army Depot (CCAD), Corpus Christi, Texas, inspects the outer mold layer (OML) of the UH-60 Black Hawk helicopter rotor blades for voids and delaminations. This process requires inspection of the blade from fore to aft and from rotor to blade tip. The current inspection process requires a technician to perform a manual "Tap" test of the blade using a small, specialized hammer. During the tapping of the blade, the technician listens for discontinuities in audible sounds produced as the hammer strikes the blade. This discontinuity normally represents a void or delamination. On average, only 4 to 6 blades can be inspected daily. This method may cause unnecessary repairs and/or missed needed repairs. CCAD requested the National Center for Defense Manufacturing and Machining (NCDMM) to review the current process and propose a nondestructive test (NDT) method of detecting voids and delaminations utilizing available state-of-the-market equipment. Several methods of inspection were evaluated at the NCDMM during the course of the project. The full UH-60 Black Hawk blade used for evaluation contained numerous voids and delaminations mapped out by CCAD technicians utilizing the manual "Tap" test method. The evaluated methods were two digital tapping hammers, two ultrasonic testing systems, two Laser Shearography systems, and a hand-held ultrasonic tester. The NCDMM recommended the implementation of the Laser Shearography technology developed by Laser Technology, Inc. (LTI). Laser Shearography systems use a common path interferometer to image the out-of-plane deformations of the test part surface.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 22, 2007
- Accession Number
- ADA481923
Entities
Organizations
- National Center for Defense Manufacturing and Machining