Free Vibration Analysis of Spinning Composite Shaft-Disk-Blade Coupled Systems

摘要

A finite element model for analyzing the vibration characteristics of composite shaft-disk-blade systems is presented here. The system consists of a composite blade attached to the rim of a rigid disk and a composite shaft to which the disk is fixed. This model is an extension of the composite blade and composite shaft models developed earlier by authors by further taking also the coupling kinetic energy of the shaft and the blade into account. The extended Hamilton's principle in conjunction with the finite element method is employed in deriving the equations of motion of the system. The dynamic characteristics such as natural frequencies, whirling speeds and mode shapes of the composite shaft-disk-blade system are studied for various material and geometry properties of the blade and shaft, as well as for various rotating speeds. The numerical results indicate that the existence of the coupling flexible motion between blade and shaft could have significant influences on the dynamic characteristics of the system. For the purpose of verification, the results obtained using the current finite element model are compared with those obtained using the available commercial software for the case of a free non-rotating shaft-disk-blade system made of an isotropic material. They are found in good agreement.