半刚性模型风洞试验荷载谱的处理方法

高频测力天平试验模型要求质量尽量小,频率足够高.然而,对于一些特殊的结构,由于结构本身的特殊性,很难制作出满足频率要求的刚性模型.对于频率不够高的半刚性模型,其一阶振型频率处于结构荷载谱频带以内,因而共振作用比较明显,对结构动力荷载的影响不可忽视.通过半刚性格构式塔架模型的高频测力天平风洞试验,得到了模型在风荷载作用下的基底弯矩和扭矩.进而根据结构动力学和随机振动理论,推导了一种实用计算公式,消除了模型共振对基底力谱的影响,得到了格构式塔架的一阶广义荷载谱.

A method to evaluate wind force spectra of semi-rigid model in wind tunnel tests

The model of high-frequency-force-balance must be light and rigid enough.However,it is very difficult to make this kind of light and rigid models for some special structures such as lattice towers because of the complexity of the structures themselves.For semi-rigid models of the special structures,the fundamental frequencies in the directions of the principal axes of the models are still in or near the frequency range of wind load spectra.In order to clear contaminations to the wind load spectra induced by model resonance,special formulae were deduced to treat the data obtained from high-frequency-force-balance tests of semi-rigid lattice tower models in light of structure dynamics and random vibration theory,and the generalized force spectra of the first mode of lattice towers in along-wind,across-wind and torsional directions are obtained.