分体式主梁桥梁颤振稳定性流固耦合数值计算研究

Flutter Stability Studies on Long Span Bridge with Central Slotted Box Girder by FSI Numerical Simulation

通过对计算流体力学商用软件FLUENT二次开发,建立了二维弯曲和扭转流固耦合数值仿真计算模型,研究6种钢箱梁桥梁方案的颤振稳定性:①整体钢箱梁;②~④不同中央开槽率的钢箱梁(开槽率分别为20%,40%和100%);⑤中央开槽与中央稳定板组合钢箱梁;⑥中央开槽与中央稳定板和水平稳定板组合钢箱梁。数值计算结果表明,对于颤振稳定性,中央开槽钢箱梁优于整体式钢箱梁;在假定主梁截面特性及桥梁自振频率不变的条件下,适当的开槽率可以使钢箱梁颤振临界风速达到最高;中央开槽与中央稳定板和水平稳定板组合钢箱梁可进一步提高桥梁颤振临界风速。数值仿真计算结果和风洞试验结果基本吻合。

By secondary development of commercial computational fluid dynamic software Fluent,the two-dimensional bending and torsional fluid-structural interaction numerical model is established to calculate flutter critical wind speed of long span bridge with central slotted box girder. There are six main girder schemes:1.Close box girder;2~4. Central slotted girder with 20%,40% and 100% slotted rate.5. Central slotted girder with 40% slotted rate and stabilizer.6. Central slotted girder with 40% slotted rate and central stabilizer and horizontal stabilizer. Numerical calculation results indicate that for streamlined box girder,the central slotted girder with appropriate width can improve the flutter critical wind speed. Assuming that the cross-section characteristics of the main girder and the natural frequencies of the bridge remain unchanged, when the slotted width reaches a certain value, the critical flutter wind speed will reach the maximum value. When the slotted width continues to increase,the flutter stability of bridge decreases. Numerical simulation results are consistent with the wind tunneltest.