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目的:明确张拉膜结构风致气弹响应特征及气弹失稳机理。,创新点:1.采用无接触测量技术设计鞍形张拉膜结构气弹模型风洞试验;2.研究鞍形张拉膜结构的气弹响应特征;3.给出鞍形张拉膜结构的失稳机理。方法:1.在风洞中测量两个形状相同但预张力不同的封闭式鞍形张拉膜结构气弹模型在不同风速下的均匀流中的位移响应及膜面上方不同高度的风速时程;2.通过对位移响应及风速时程进行,分析,明确结构的响应随风速变化特征及气弹失稳原因。.结论:1.膜结构在风荷载作用下变形到平衡位置,并.围绕该平衡位置以特定振幅进行振动;2.大部分风向角下,多个模态被激发,结构振幅及各阶模态阻尼比随风速增大而逐渐增大;3.特定风向角下,只有单阶模态被激发;低风速下,结构振幅和模态阻尼比随风速增大而缓慢增大;超过一定风速后,结构发生涡激共振引起的气弹失稳,振幅随风速增大开始迅速增大,达到不发生涡激共振时的2–4倍,结构阻尼比随风速增大发生迅速衰减;随着风速的继续增大,结构振动中可能出现其他模态的气弹失稳;4.结构前两阶模态的无量纲气弹失稳临界风速约为0.8–1.0。
Objective: To clarify the wind-induced aeroelastic response of tensioned membrane structure and the instability mechanism of aeroelasticity. , Innovations: 1. Design of saddle-shaped tensioned membrane aeroelastic model wind tunnel test using non-contact measurement technology; 2. Study the aeroelastic response characteristics of the saddle-shaped tensioned membrane structure; 3. Give the saddle tensioned membrane structure The instability mechanism. In the wind tunnel, the displacement response of two kinds of closed-type saddle-shaped tensioned membrane-structure aeroelastic model with the same shape but different pre-tension in uniform flow under different wind speeds and the wind speed time-series with different height above the membrane surface ; 2. Through the displacement response and wind speed time history, analysis, a clear structural response characteristics with changes in wind speed and gas instability reasons. .Conclusions: 1.The membrane structure deforms to the equilibrium position under the wind load and vibrates with a certain amplitude around the equilibrium position. 2.Most modes are excited in most of the wind direction angles, State damping ratio increases with the increase of wind speed. (3) Only single-mode mode is excited under specific wind direction angle; at low wind speed, the amplitude and mode damping ratio of structure increase slowly with the increase of wind speed; After a certain wind speed, the aeroelastic instability caused by vortex-induced resonance occurs in the structure. The amplitude increases rapidly with the increase of wind speed and reaches 2-4 times of that without vortex-induced resonance. The structural damping ratio increases rapidly with the wind speed Attenuation; As the wind speed continues to increase, structural vibration may appear in other modal aeroelastic instability; 4. The first two modes of the structure of non-dimensional critical aeroelastic instability wind speed is about 0.8-1.0.