颤振临界风速计算值与试验值的一致性

为了准确把握扁平箱梁的颤振性能，采用节段模型风洞试验和颤振计算相结合的方法，研究了扁平箱梁断面在不同风攻角下颤振临界风速计算值与试验值的一致性.首先通过强迫振动风洞试验获得了某箱梁断面模型颤振导数；然后通过耦合颤振闭合解法获得了不同动力参数条件下的颤振临界风速；最后通过弹簧悬挂节段模型风洞试验测试获得了相同参数条件下的颤振临界风速.计算值和试验值对比结果表明:在0°攻角下扁平箱梁模型颤振临界风速的计算值与试验值保持一致，6种工况下两者差异分别为0.12%、0.50%、4.90%、4.10%、4.84%和1.43%；当风攻角为3°和5°时，颤振临界风速的计算值与试验值较难保持一致，最大差异值可到10.4%；通过对比颤振因子在计算和试验条件下的离散性，在排除非线性气动力和结构阻尼的影响后，推测造成此差异的原因是耦合颤振运动中相位角的变化引起了颤振导数的变化. 

Consistency between Calculated and Tested Values of Critical Flutter Speed of Flat Box Girder

To obtain the precise flutter performance of a flat box girder, concordances between calculated values and tested values of critical flutter speed were studied, using sectional model wind tunnel testing combined with the calculation method of critical flutter speed. The flutter derivatives under different wind attacks of the box girder were obtained using forced vibration tests. The critical flutter speeds were then calculated using the bimodal coupled flutter analysis method. Finally, the critical flutter velocities were obtained via the sectional model tests under the same conditions. The results indicate that the differences between calculated and tested critical speeds in all cases are minor, and the percent errors are less than 5% when the attack angle is 0°. The differences between calculated and tested critical speeds are substantial when the attack angles are 3° and 5°, and the percent error can reach 10.4%. Based on a comparison of flutter factors derived from the calculation and the test, excluding the effect of nonlinear aerodynamic force and structural damping, it is conjectured that the differences may have been induced by variation in flutter derivatives caused by different coupled motions.