Grant: Applied Research and Development Grants - Level 1

The primary function of helicopter skid landing gears is to absorb all the impact energies during an event of hard landing or a crash and provide utmost safety to the occupants. Skid landing gears are made of two skids that are linked together and to the fuselage by two cross-tubes of circular cross-sections. Cross-tubes are the primary crash attenuating components in the landing gear. In an effort to replace chemical milling by another process for the manufacturing of cross-tubes, a novel variable stiffness design based on non-circular cross-sections has been developed for a cross-tube that could be produced by hydroforming or other plastic deformation processes. However, the high strength aluminum alloys used for cross-tubes pose forming challenges due to their high mechanical properties and relatively low ductility. Therefore, the aluminum alloy must be well characterized, including the effect of natural ageing on the properties and formability of the tubes, as well as the effect of the plastic deformation on subsequent artificially aged parts, in terms of mechanical properties. All this information is required to correctly model the behavior of the material during forming and in-service life, and to tailor the ageing heat treatment to the parts and process. This project will help the industrial partner to assess the feasibility of forming the tubes by hydroforming or other plastic deformation process and provide them information about the final properties of the cross-tubes.