Free Vibration of Spinning Fiber Reinforced Composite Shaft-Disk-Blade Systems

• Main Authors: Chang Chih Yung, 張智勇
• Other Authors: Chang Min Yung
• Format: Others
• Language: en_US
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/20861312978076516384

博士 === 國立中興大學 === 機械工程學系 === 92 === 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 Chang et. al. 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 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. The dynamic behaviors of the rotating composite shafts containing randomly oriented reinforcements are furthering investigated in this study. Incorporating the Mori-Tanaka mean-field theory to account for interaction at finite concentrations of reinforcements with the equivalent inclusion method, the effective elastic moduli are expressed as a function of phase properties, volume fraction, orientation angles, and reinforcements’ shape. Based on shaft’s model and taking these effective elastic moduli into account, the natural frequencies of the stationary shafts, and the whirling speeds as well as the critical speeds of the rotating shafts are presented.