Cast Aluminum Primary Aircraft Structure
Abstract
A A357 cast aluminum alloy forward fuselage pressure bulkhead has been developed and manufactured for the AMST-YC-14 aircraft. This work was performed by The Boeing Company under the direction of the AFFDL/AFML-AMS/ADP office as part of the Cast Aluminum Structures Technology (CAST) contract. The purpose of the program is to demonstrate that aluminum castings can be used for primary aircraft structural components with no weight penalty and a minimum of 30% cost savings. To assist in the development of the design and in the demonstration of the structural integrity of the cast bulkhead, an extensive test program was undertaken to study the static strength, and fatigue and fracture characteristics of A357-T6 cast aluminum alloy. Static mechanical properties, S-N data, and crack growth and fracture toughness data were generated. The integrity of the design was demonstrated by analysis. The concepts of linear fracture mechanics were applied in the damage tolerance analysis. No casting factors were used in the design and analysis. Data were collected on the effects of defects commonly occurring in castings. Test coupons were removed from castings containing defects and subjected to repeated loads. The shift of the S-N curve for A357 aluminum alloy was determined for a number of typical defects. The effects of defects were also expressed as equivalent initial flaws assumed to be located at the defect site. Repair/no repair decisions for the production castings were based on an evaluation of the load environment and the effect of the defect on fatigue and fracture properties.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1979
- Accession Number
- ADA108145
Entities
People
- C. K. Gunther
Organizations
- Boeing Military Aircraft