有限元方法计算桥梁涡激振动响应

Calculation of Vortex-Induced Vibration of Bridges by Finite Element Methods

本文研究用有限元法计算桥梁涡激振动的时程响应。应用条带假设和半经验半解析的Scanlan第二涡激作用力模型实现涡激作用力在时间和空间上的离散化;针对Scanlan模型中Van der Pol性质的时间频率混合项,引入时频混合格式的AFT方法来计算涡振时程响应,并通过算例验证了该方法的可行性。与传统的连续模型和随机振动理论计算桥梁涡激响应方法相比,时程计算可以考虑多振型的组合作用,结构非线性等多种影响,具有更大的灵活性。

This paper studies the calculation of vortex-induced responses of bridges by finite element models. The strip theory in conjunction with the half empirical and half analytical second Scanlan's vortex shedding model is employed to discretize the vortex-excitation force in both time and space.An Alternating Frequency Time (AFT) domain method is introduced to solve the assembled equations accounting for the mixed time-frequency terms of the Van der Pol type in Scanlan model. Numerical results are presented to demonstrate the accuracy and effectiveness of this new method.This proposed approach is verified to be a more flexible means to analyze vortex-induced vibrations than those traditional continuous model and stochastic approaches. Time history response calculation is more flexible than the conventional continual model and random vibration theory in that it may take into account of the multi-mode effects and structure nonlin-earity.