复杂三维外形旋翼气弹稳定性分析

Aeroelastic stability analysis of rotor blade with complex three-dimensional design

针对带有后掠、下反构型的复杂三维外形旋翼气弹稳定性问题进行分析。基于中等变形梁理论以及Hamilton原理,在桨叶运动学描述中引入节点转换矩阵在有限元总体阵组集中引入变形相容原则,建立面向复杂三维外形旋翼的结构动力学模型,并在算例验证的基础上针对复杂三维外形旋翼气弹稳定性问题展开参数影响分析。研究表明:桨尖后掠引起挥舞-扭转结构负耦合效应,造成一阶扭转模态频率和模态阻尼比降低,一阶扭转模态阻尼最大降低90%;桨尖下反引起摆振-扭转结构正耦合效应,造成二阶摆振模态频率降低,一阶扭转模态阻尼比最大降低62%,采用后掠带下反设计会大大降低扭转稳定性。

A rotor dynamic analysis method for the complex three-dimensional design blade was developed and applied to analyzing its aeroelastic stability.Based on the medium-size deformation beam theory and Hamilton principle,the joint transfer matrix was used in the blade kinematic and the deformation compatibility principle was used in the assembled finite element matrix to develop the complex three-dimensional rotor structural dynamics model.The BO105 rotor was used to validate this method and the aeroelastic characteristic of the complex three-dimensional rotor was analyzed in detail.The results showed that the negative structural coupling of flap-torsion was appeared with tip sweep,and the 1/rev torsion modal frequency was decreased,and the 1/rev torsion modal damping ratio was maximally decreased about 90%.The positive structural coupling of lag-torsion was appeared with tip droop,the 2/rev lag modal frequency was decreased,the 1/rev torsion modal damping ratio was maximally decreased about 62%.The torsion stability was sharply decreased with tip sweep and droop design.