弦支穹顶结构动力稳定性分析方法

系统阐述了弦支穹顶结构动力稳定性分析方法,论证了基于严格数学定义的Lyapunov运动稳定性理论和方法不能对地震作用下的非线性、多自由度系统的稳定性提供有效判别准则.提出了基于B-R运动准则的改进判别方法,以此为基础结合结构的时程响应曲线判定弦支穹顶结构的动力稳定性,分别研究了水平、竖向和三向地震作用对不同矢跨比弦支穹顶结构动力稳定性、稳定形态及拉索形态的影响.研究表明,不同地震作用下结构的失稳形态不同,矢跨比对结构动力稳定性能的影响不同;矢跨比不同,对结构稳定性起控制作用的地震作用分量不同;地震加速度接近临界值时,一些拉索开始逐步退出工作状态,但在振动过程中可能重新产生张拉力.

Analysis Method of Dynamic Stability of Suspended-Dome Structures

Analysis methods of the dynamic stability of suspended-dome structures were discussed.A theoretical investigation was conducted based on the Lypumov dynamic stability theory.The investigation shows that it is difficult to obtain the dynamic instability criterion of a suspended-dome structure under an earthquake with the current methods and the Lypumov theory.Based on the B-R(Budiansky-Roth) criterion,a practical method to judge the dynamic stability was proposed.With this method and time history response curves,the dynamic stability of a suspended-dome structure was judged.Under horizontal,vertical and three-dimensional seismic excitations,the dynamic stability characteristics,stability configuration and cable behavior of suspended-dome structures with different rise-span ratios were analyzed respectively.The results show that under different seismic excitations,the critical dynamic instability configuration is different,and the effects of the rise-span ratio on the dynamic stability are different.The dominant earthquake components of the dynamic instability of the structures with different rise-span ratios are different.When the exciting acceleration approaches the critical point,some cables will relax,but they will be tensioned again during later vibration.