Design and Performance of energy Absorbing Subfloor Structures in Aerospace Applications

Kurzfassung

Composite elements such as glass or carbon fibre reinforced tubes in axial crush exhibit high specific energy absorption and a challenge for the engineer is to utilise these properties in structural applications. The paper considers the application of composites in the design of helicopter and aircraft subfloors with a dual function of beeing structural elements under flight loads, which may be triggered to absorb energy by folding and crushing under crash loads. Examples discussed are an energy absorbing (EA) floor beam concept for a general aviation aircraft based on sandwich webs with glass and aramid fabric/epoxy face plates and box element core, and a modular helicopter subfloor concept with hybrid carbon/aramid/epoxy beams and cruciform elements. Progress on the development of design tools for these crashworthy structures based on FE simulation is also discussed and simulation results compared with crash test data.