预张力膜片风振反应的试验研究

Wind-Induced Dynamic Response Tests of Tensile Membrane Sheets

针对张拉膜片在确定的预应力水平下的风振反应来考察它的模态和风振特性,采用膜面预应力检测仪测量了试验中膜片的预应力水平。膜结构的振动形式经常是以高阶振型为主,基频随预应力水平的增大而增大。预应力水平越高,各阶模态对应的阻尼比相差越小;反之,气动阻尼越集中在低阶模态。与风速和预应力水平相比,膜面倾角对膜面位移风振系数的影响更为显著,并对不同倾角的膜面位移风振系数提出了建议值。部分工况下膜片出现颤振,膜面倾角和较低的预应力水平是诱发颤振的主要因素。

In this paper,the modal performance and wind-induced dynamic performance of tensile membrane sheets under assured prestress level were investigated with wind tunnel tests.Membrane prestress measuring instrument was used to measure the prestress.High vibration modes were always observed.Fundamental frequency increased with the prestress.Difference of damping ratio for different modes decreased with the prestress.Whereas,the aerodynamic damping concentrated on low modes with low prestress.Compared with the wind velocity and the prestress,the membrane angle had a marked influence on the wind-induced dynamic factor of the membrane displacement. The factors for different membrane angle are proposed.In some cases,flutter phenomena were observed.The low prestress and certain membrane angle were main reason.