地震作用下矩形柱体动水压力的简化模型

Simplified Model for the Earthquake Induced Hydrodynamic Pressure on Rectangular Cylinder

为了解决地震作用下矩形柱体在水中的振动问题,提出一种水-结构动力相互作用的简化模型.首先,建立地震作用下矩形柱体与周围水体动力相互作用的动力方程,方程中矩形柱体与周围水体的相互作用是通过附加质量矩阵实现的,需要指出的是该附加质量矩阵的满阵特性导致其难以在商业有限元软件中实现;其次,提出集中附加质量矩阵模型,包括刚性运动和柔性运动引起的附加质量,其中柔性变形与水体的相互作用为刚性运动引起的附加质量乘以修正系数,并通过曲线拟合建立不同长宽比时该修正系数随宽深比变化的计算公式;最后,通过对刚性矩形桥墩动水力数值解的曲线拟合,建立了矩形柱体分布动水力的简化计算公式.

A model for the flexible rectangular cylinder vibrating in water was presented to simulate the fluid-structure dynamic interaction.First,the dynamic equation for the water-cylinder dynamic interaction under earthquake action was developed by finite element method.The water-cylinder interaction was represented by an added mass matrix,which was fully populated.However,the fully populated added mass matrix was difficult to be implemented in the commercial software.Then,a simplified model that used the lumped added mass matrix corresponding to the rigid motion and flexible motion to replace the fully added mass matrix was presented.It should be noted that the added mass caused by flexible motion was the product of the lumped added mass matrix and a correction factor.Based on the curve fitting method,the simplified formulas of the correction factor under different length-width ratio relevant to width-depth ratios were eproposed.Finally,the simplified formulas for the earthquake induced hydrodynamic forces on rigid rectangular cylinder were proposed by curve fitting method.