Fractographic Inspection of the Cracking FT488/2 Removed at Program 79
Abstract
During the inspection of the FT488/2 Bare Bulkhead Fatigue Test specimen after 79 blocks of applied loading, the starboard upper wing-attachment hole aft edge, port lower wing-attachment hole aft edge and the port upper wing-attachment hole aft edge, were found to have crack indications. This cracking was confirmed by dye penetrant inspection of the regions under load. Each of the cracked holes had multiple corner cracks, with crack depths estimated to be no more than 1 mm. With the bushes removed from the holes, the cracking appeared to be confined to the aft edges of the holes. To assess the true extent of the cracking, the crack growth rate and nature and influence of the initiating flaws, the areas containing the cracks were cut from the bulkhead. Sixteen of the cracks were broken open for analysis and several sections were cut adjacent to the cracked regions to assess the microstructure. Apart from the wing-attachment hole cracks, one of the four-inch radii (starboard forward) also had a crack indication. This area was removed. No cracking could be found although a defect in the ion vapour deposited aluminium coating in the region of the suspected crack was noted and was probably responsible for the indication.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1998
- Accession Number
- ADA355953
Entities
People
- S. A. Barter
Organizations
- Defence Science and Technology Group