Dynamic response of coupled shaft torsion and blade bending in rotor blade system

This study develops a computational model for the dynamic characteristics of a rotor-blade system. The rotor-blade coupled model with pre-twisted blade attached to a rigid disk driven by a shaft is developed using the Lagrange equation in conjunction with the assumed mode method to discretize the blade deformation. The effects of axial shortening due to blade lagging deformation, centripetal force caused by the rotating blade, and gravity are included in the model. The coupled equation of motion is formulated based on the small deformation theory for the blade and shaft torsional deformation to obtain the dynamic characteristics of the system for various system parameters. Numerical simulations show that the pre-twist angle of the blade and the shaft torsional flexibility strongly influence the dynamic behavior of the rotor-blade system.