Stability of Pretwisted Tapered Beams with Randomly Varying Rotating Speeds

• Main Authors: Tien-Ming Lin, 林天明
• Other Authors: Tiau-Her Yang
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/39147301287257184883

碩士 === 國立臺灣科技大學 === 機械工程研究所 === 83 === In this study, the blade is modeled as a pretwisted,tapered beam, and the rotating speed of the blade is assumed as a constant speed superimposed by a Gaussian white noise process. First, the equation of motion is derived by Hamilton's principle, then a one-term Galerkin method is utilized to discretize the continuous system into a two degree of freedom system. Next, by assuming the disturbance of rotating speed is of small intensity, the Ito equations are obtained by the method of stochastic averaging. Finally, the stability boundaries of the system are decided by using the second moment stability criteria and almost sure stability criteria, respectively. The effects of system parameters on the stability boundaries are studied numerically, and the relationship between these two stability criteria is also investigated.