Equivalent Modelling and Modal Analysis of Bearingless Tail Rotor based on Beam Model
During the modal test of the bearingless tail rotor,there is a great difference between the same order symmetric and antisymmetric shimmy frequency.In order to reveal the reason of the fre-quency difference,the finite element analysis and experimental study of the bearingless tail rotor were carried out.When establishing the finite element model of the bearingless tail rotor,consider-ing the characteristics of the multi-channel force transmission and the complex root boundary con-straints of the bearingless tail rotor,the step-by-step modeling method was adopted.In the first step,the equivalent beam in the clamping zone of the flexible beam root was calculated based on the static condensation method,and the equivalent stiffness of the root section was obtained.The second step was based on the three-dimensional equivalent beam model calculation method,the finite ele-ment beam model of the bearingless tail rotor was established by using ABAQUS software.The dy-namic characteristics of the bearingless tail rotor under different root boundary constraints were ana-lyzed and studied,and the static dynamic characteristic tests under different root boundary condi-tions were carried out.The calculated results were in good agreement with the experimental results.The results showed that the root boundary condition of the flexible beam had a great influence on the blade shimmy mode frequency,which was the reason for the great difference between the blade shimmy frequency of the same order symmetric type and anti-symmetric type.The step-by-step modeling method could take into account the accuracy and efficiency of the calculation of dynamic characteristics of bearingless tail rotor,and met the requirements of engineering design.
helicopterbearingless tail rotorfinite element modelingmodal analysis
万方数据
维普
