确定桥梁模型颤振临界风速的实用方法

PRACTICAL TECHNIQUE FOR DETERMINING CRITICAL FLUTTER WIND SPEED OF BRIDGE MODEL

建立了根据18个颤振导数求解三自由度颤振方程,搜索颤振临界风速的双参数优化模型;将苏通大桥、荆沙大桥和苏拉马都大桥主梁颤振导数代入该优化模型,搜索得到了各自颤振临界风速,并与风洞试验实测及复模态颤振分析结果进行对比,分析了引起差异的主要原因。分析了系统质量、质量惯矩和阻尼对荆沙大桥颤振临界风速的影响;分析了18个颤振导数对苏拉马都大桥颤振临界风速的影响。分析结果表明:双参数优化模型为评价颤振导数的识别精度和定性分析颤振临界风速对颤振导数的敏感性提供了一种有效途径,颤振导数H3*,A1*,A2*对苏拉马都大桥颤振风速影响较为显著,P1*(i=1～6)对颤振风速影响不明显。

An optimization model involving twin undetermined parameters was presented,by which 3-DOF flutter equation concerning eighteen flutter derivatives can be solved and the critical flutter wind speed be searched.By introducing the flutter derivatives of the decks of Sutong bridge,Jingsha bridge and Suramadu bridge into the optimization model,their critical flutter wind speeds were obtained,and compared with the experimental and the analytical modal flutter results.The major reasons incurring the difference were analyzed.The influences of system mass,mass moment of inertia and damping on the critical flutter wind speed of Jingsha bridge were investigated.The influence of 18 flutter derivatives on the critical flutter wind speed of Suramadu bridge was studied.The analytical results indicate that the optimization model involving twin parameters is an effective approach for evaluating identification precision of flutter derivatives,and for analysing qualitatively the sensitivities of the critical flutter wind speed to flutter derivatives.The flutter derivatives H2,A1,A2 play the most important role on the flutter wind speed of Suramadu.The influence of Pi(i=1~6)on the flutter wind speed is minor.