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非对称П型梁和流线型箱梁气动性能风洞试验研究 预览

A study on the aerodynamic characteristics of an asymmetric П shaped girder and an asymmetric streamlined box girder via a wind tunnel test
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摘要 为了研究非对称人行道对主梁气动性能的影响,利用节段模型风洞试验,分别研究了非对称П型梁和流线型箱梁在不同来流风向下的三分力系数、涡振以及颤振特性。试验结果表明:在正攻角范围内,0°来流风向下(人行道板一侧的来流方向)两种类型主梁的三分力系数均大于180°来流风向值,且非对称人行道对П型梁三分力系数的影响比流线型箱梁显著;断面的非对称性会严重影响不同来流风向下П型梁的涡振性能,包括出现涡振的风攻角、涡振响应振幅、起振风速以及锁定区间等。从空气动力学角度分析,人行道板的存在使0°风向来流提前发生分离,再附点发生改变,涡激力减弱,进而改善了主梁在该来流风向的涡振性能。0°来流风向下两种类型非对称主梁的颤振临界风速均高于180°来流风向值。颤振导数结果显示非对称人行道板和栏杆可提供一定的扭转气动正阻尼,因此0°来流风向主梁的颤振临界风速较高。 To study the effects of the asymmetric foot-rslabs on the aerodynamic characteristics of main girders, the aerostatic coefficients, the performance of vortex-rinduced vibration (VIV) and flutter of both an asymmetric П shaped girder and an asymmetric streamlined box girder were investigated via a section model a wind tunnel test in different flow directions. The test results show that the aerostatic coefficients in the 0° flow direction (the flow comes from the foot-slab direction) are larger than that in the 180° flow direction for two types of asymmetric girders under positive attack angles. The impact induced by asymmetric foot-slabs on the aerostatic coefficients of the П shaped girder is more significant than the streamlined box girder. The asymmetric property has a significant effect on the VIV performance of the П shaped girder, including the attack angle, the amplitude of VIV response, the vibration critical wind speed and the lock-in regime et al. From the perspective of bridge aerodynamics, the flow separates in advance, the reattachment positions change and the VIV forces decrease, which may be attributed to the existence of the foot-slab in the 0° flow direction. The VIV performance of main girder is thus improved in the 0° flow direction. The critical flutter wind speeds of two types of asymmetric girders in the 0° flow direction are higher than that in the 180° flow direction. The results of flutter derivatives show that the asymmetric foot-slabs and railings can provide a positive torsional aerodynamic damping. A high critical flutter wind speeds of main girder can thus be achieved in the 0° flow direction.
作者 李明 孙延国 李明水 周强 LI Ming;SUN Yanguo;LI Mingshui;ZHOU Qiang(Department of Bridge Engineering,Southwest Jiaotong University,Chengdu 610031,China;Wind Engineering Key Laboratory of Sichuan Province,Southwest Jiaotong University,Chengdu 610031,China)
出处 《振动与冲击》 EI CSCD 北大核心 2019年第8期54-60,共7页 Journal of Vibration and Shock
基金 国家自然科学基金(51408505 51478402).
关键词 非对称主梁 气动性能 风洞试验 涡激振动(VIV) 颤振 asymmetric girder aerodynamic characteristic wind tunnel test vortex-induced vibration(VIV) flutter
作者简介 第一作者:李明,男,博士生,1990年生;通信作者:孙延国,男,博士,讲师,1981年生.
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