Boron/Aluminum Landing Gear for Navy Aircraft.
Final rept. Jun 74-Aug 77.
GENERAL DYNAMICS SAN DIEGO CA CONVAIR DIV
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The program objective was to evaluate the application of boronaluminum 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 boronaluminum 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 boronaluminum 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 tubefitting scarf joint was performed. Boronaluminum 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 boronaluminum links and the 300M steel production link were notched and tested in the same sequence.
- Attack and Fighter Aircraft
- Laminates and Composite Materials