支撑刚度对飞翼模型固有模态和体自由度颤振特性的影响

The influence of the support stiffness on the natural modes and body freedom flutter characteristics of a flying wing model were investigated. Firstly, the semi-span structural dynamical FEM model and flutter model were built for a typical flying wing, and the free-free symmetric modes and body freedom flutter characteristics were calculated. Next, in order to model the typical support conditions in wind tunnel test, vertical spring and torsional spring were attached to the mass center of the model. The natural frequencies and flutter characteristics were calculated with respect to different combination of support stiffness. The results show that the rigid body mode frequencies of the flying wing model increase with the support stiffness. The impact of torsional spring on the first bending mode frequency of the wing is greater than that of the vertical spring. Pitching/plunging coupled flutter will occur at very low airspeed with vertical support only. However, the pitching/wing first bending mode coupled flutter will arise with torsional support only. It is indicated that one may obtain similar body freedom flutter result to the free-free case by carefully adjusting the combination of the support stiffness of the vertical spring and torsional spring to ensure the pitching mode frequency exceeding the plunging mode frequency by a certain extent. This research is relevant to the suspension design of the wind tunnel test model of the flying wing body freedom flutter.