Use of moving four-degree-of-freedom spring-damper-mass element for the vibration analyses of a beam subjected to moving loads

• Main Authors: Chung-Chin Liu, 柳忠勤
• Other Authors: Jia-Jang Wu
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/90787455801797219154

碩士 === 國立高雄海洋科技大學 === 輪機工程研究所 === 101 === In order to take the rotational inertia effects, translational inertia effects, spring effects and damping effects of the moving load into account, this paper presents the theory of moving four-degree-of-freedom spring-damper-mass element which consists of a lumped mass , two roller masses ( ), two springs ( ) and two dampers ( ). The element property matrices of the last element are derived based on the dynamic equilibrium equations of the moving spring-damper-mass (SDM) system. Since the interactions between the moving SDM system and the supported structure is considered, by means of shape functions, in the last matrices, the latter are time-dependent, so are the overall property matrices of the entire vibrating system. Newmark direct integration method is used to solve the equations of motion and determine the dynamic responses of the whole structure. Some factors, such as moving speed, spring constants and the position for centre of gravity of lumped mass of the SDM system, closely relating to the title problem are investigated. Numerical results show that the influences of the foregoing parameters on the dynamic responses of either the moving subsystem or the supported structure are considerable.