Boron/Aluminum Landing Gear for Navy Aircraft.
Abstract
The program objective was to evaluate the application of boron/aluminum composite material to a typical Navy landing gear component, with primary emphasis upon evaluation of component reliability. A replacement composite drag link was designed using boron/aluminum tube construction to the required envelope, ultimate loads, fatigue spectrum, and carrier environment for the A-7 nose gear lower drag link. The resulting composite link design was a 28-ply boron/aluminum tube diffusion bonded to titanium end fittings. A test specimen was designed identical to the replacement composite drag link, except that simplified test end fittings replaced the complex flight fittings. A comprehensive stress analysis was conducted for both the replacement drag link and the test specimen. A finite-element computer analysis of the critical tube/fitting scarf joint was performed. Boron/aluminum links that had been damaged by pebble impact then subjected to a corrosive environment and notched, showed no reduction in static strength over an as-fabricated specimen and survived two lifetimes at 80% design fatigue load levels. This compared favorably with a notched 300M steel production link which failed in fatigue after 1.1 lifetimes at 70% design fatigue load levels. Both the boron/aluminum links and the 300M steel production link were notched and tested in the same sequence.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1978
- Accession Number
- ADA058888
Entities
Organizations
- General Dynamics