MECHANICAL PROPERTIES OF THE SUPPORT STRUCTURE WITH RECOVERABLE STIFFNESS

The Fan Blade-Off event can have a significant impact on the rotor, and fuse structures are commonly employed to absorb the resulting energy. However, fused structures often lead to excessive loads on other bearings. In this paper, we propose a support structure with recoverable stiffness, integrating a chiral structure using shape memory alloy and a folding squirrel cage. The mechanical properties of chiral unit-cells with various configurations are analyzed. An analytical model of the support structure is established to examine mechanical properties, and the findings are validated through experiments. The support structure can effectively absorb impact energy through the phase transition of materials. The support stiffness rapidly decreases, reaching negative stiffness, and can be restored through heating. Experimental results indicate that the support stiffness aligns with the analytical model, with a stiffness reduction ratio of up to 61.81%. The support stiffness can be fully restored, and the loss factor of the support structure is 0.32. The proposed support structure proves to be effective in absorbing impact energy and achieving stiffness recovery. This, in turn, reduces rotor amplitude and enhances rotor working stability. It stands as a secure and efficient support structure capable of handling impact loads.