SIGNIFICANT PROPERTIES OF ALUMINIUM LIGHT ALLOYS IN THE DESIGN OF ENERGY ABSORBING AIRCRAFT STRUCTURES

摘要

The paper summarises the fundamental aspects of the design of structures and structural parts in aluminium light alloys in cases when energy absorption performances are required. Particularly, the design of crashworthy helicopter structures and the development of leading edges, for wings or tail empennages, in bird impact conditions are considered. In both cases the structural performance turns out to be strongly influenced by the material properties beyond the elastic range, such as the ultimate strength, the overall toughness, the elongation at failure and the strain rate sensitivity of the plastic response. The design conditions of crashworthy helicopter structures are referred to potentially survivable crash scenarios where the absorption of the impact energy by means of absorbers located in the landing gears, in the subfloor and in the seats can significantly reduce the occupant injuries (Figure 1).