Castings on airliners
Castings on airliners
Keywords Aircraft,Alloys, Castings
A panel of experts convened to examine why castings are not in wider use on airliners has concluded that the major barriers are lack of design data, designer ignorance of the benefits of the casting process, and long lead times. The panel, made up of foundry suppliers, airframe engineers, and academic researchers, met recently. The meeting was sponsored by the Institute for Mechanics and Materials at the University of California at San Diego, which published a report on the panel's findings entitled "Engineering issues in the use of premium quality airframe castings in commercial aviation".
Several different casting alloys are currently used on the Boeing 777. For example access doors, engine equipment supports, and door hinges are currently cast of aluminium alloys. An auxiliary power unit exhaust duct is cast of titanium.
A new structural application has also been developed: the electrical equipment access door on the Boeing 757. The panel concluded that to increase the number of applications, a comprehensive study of damage tolerance in cast alloys is needed. Airframe designers have 60 years of experience in the design of built-up structures (ribs with aluminium skin fastened with rivets). However, if they are to expand their use of castings they need to know how cracks would grow in a monolithic casting,and how this damage tolerance compares with that of the built-up structure.
The panel also called for reduction of hard tooling lead times by 50 per cent, development of non-destructive inspection techniques to minimize error, and correlation of non-destructive evaluation indications with actual service performance.
For further information contact Institute for Mechanics and Materials, University of California at San Diego, 9500 Gilman Drive, Department 0404, La Jolla, California, 92093-0404. Tel: +44 (1) 619/534 7503.
