深水桥墩流固耦合下的自振特性研究

首先探讨了深水桥墩流固耦合下动力特性研究的有限元理论和建立计算模型的方法。研究了桥墩墩水耦合分析中流体单元网格尺寸、流体范围对深水桥墩动力特性数值解精度的影响,得出了工程中常见的墩水耦合分析较优水体单元尺寸和理想水体范围图。计算分析了矩形、圆形和圆端型截面深水桥墩的自振特性,实心墩在水中的自振频率降低10%～20%之间。空心墩频率降低幅度大于实心墩,与截面尺寸和壁厚密切相关。水体对空心墩的振型也有一定影响。进一步研究了淹没深度、桥墩截面尺寸以及空心墩壁厚对深水桥墩频率降低幅度的影响,得到有益的结论。该研究方法以及相关结论可以对墩水耦合问题的进一步研究以及工程应用提供参考。

Natural vibration properties analysis of deep-water piers based on fluid structure interaction

The finite element theory of fluid structure interaction has been studied and a new method to modeling pier-water coupling has been introduced firstly. Then the fluid element mesh size and fluid scope, which are influencing factors of calculation precision, have been discussed, so as to achieve better fluid element mesh size and appropriate fluid scope for commonly used piers in engineering. Natural vibration properties of rectangular piers ,circular piers and round-ended piers have been calculated ,which shows that vibration frequency of solid deep-water piers descend 10% ~ 20% than that in air, and hollow deep-water piers descend more than solid ones the vibration frequency of hollow deep-water pier is mainly affected by section dimension and wall thickness, and vibration mode is to be affected also. Further,the influence parameters of frequency decreased degree such as water depth, pier section dimension and wall thickness of hollow pier have been researched,and useful results have been achieved.