直升机桨叶刚柔耦合特性及计算方法分析

为了研究桨叶刚柔耦合特性,采用中等变形梁模型处理桨叶弹性变形,分别采用小转角和有限转角两种方法处理桨叶绕铰的刚性运动.以桨叶扬起下坠碰撞问题为研究对象.计算分析表明:(1)弹性桨叶存在较明显的刚性运动和弹性变形耦合;(2)挥舞角较小时,两种处理方法计算结果一致,均与试验数据吻合较好;(3)挥舞角较大时,刚柔耦合增强,两种处理方法的计算值差别较为明显;(4)桨叶弯曲刚度对桨叶刚柔耦合特性有较明显影响,刚度越小,耦合越强;(5)桨叶如果比较柔软,小转角处理方法计算值相对有限转角处理方法,相位滞后、幅值增加均较为明显,计算桨叶动响应时需引起注意.

Analysis of the Computational Method and the Helicopter Blade Characteristics with Coupled Rigid and Elastic Motions

In order to investigate the coupling characteristics between elastic deflections and rigid motions of the blades,the moderate deflection beam model was adopted to treat elastic deflections and two methods were adopted to treat rigid motions based on infinitesimal rotation and finite rotation.The impact problem of the blade droop stop was analyzed.Results show:(1) coupling of elastic deflections with rigid motions is distinctive;(2) computations of two methods are in good agreement with test data,when rotation angle is small;(3) when rotation angle is large,couplings increase distinctly and the differences between the results of the two computational methods increase;(4) the bending stiffness has evident effect on the coupling,and the coupling will increase with the decrease of bending stiffness;(5) in case of the blade is relatively soft,the calculated values of phase lag and amplitude augment based on infinitesimal rotation will exist.This phenomenon should be paid attention to,when blade dynamic response is calculated.