Response Analysis Of Flexible Risers Subjeted To Vortex-Induced Vibration In Sheared Flow

Vortex-induced Vibration(VIV) is a common phenomenon in engineering situations. It draws a lot of attention in Ocean Engineering, Wind Engineering and Bridge Engineering due to the fact that in some case it takes most of the responsiblies for the damage of structures from fatigue and intensity failure. Therefore, it is of great importace to acurrately predict the response subject to Vortex-induced Vibration and explore the effective ways to supress it.This thesis first reviews the relative studies on the phenomenon of Vortex-induced Vibration and summarizes the descriptions of its enssence in current literature. A computer program to predict the response of VIV is generated on that basis. Specific topics are listed as below:(1) For flexible risers and marine cables, a program to predict the response of VIV is generated using MATLAB. In it a analytical method to sovle the linear models of flexible structures is proposed, taking into account the effect of axial forces. The response of flexible risers both in time domain and frequency domain is prediced through this program.(2) A parameter analysis is performed using the self-written program. Those parameters of concern are the density of risers'material, tension applied on the top, the bondary conditions and so on.(3) Vibration coefficients of fractal participation for the non-resonant models in the global response of VIV are solvedThe computer program referred to in this thesis is based on all kinds of empirical models established through expriments but on finite element method. For this reason, it can perform the computation more quickly. Obviously, to achieve more acurrate empirical models will make the program more effective in predicting the response, which means a lot to its application to the engineering design.