以单层凯威特球面网壳连续倒塌全过程非线性仿真计算为例,通过对地震过程中结构构件变形、受力、损伤等参量发展特征的研究分析,提出单层球面网壳连续倒塌过程可分为3个阶段,阐述了结构连续倒塌全过程的机理.分析不同地震峰值加速度条件下这3个阶段中结构重心竖向位移的变化特征,在此基础上,提出了适用于单层球面网壳结构的性态水平描述,并建立基于结构重心竖向相对位移的损伤评估指数.这些工作对于空间结构强震下灾变机理的进一步研究有较好的参考意义.
Based on nonlinear simulation of progressive collapse of single-layer Kiewitt spherical shell, this paper studies the characteristics of deformation, load-bearing, and damage development of members, and presents a theory called three-phase that explains the progressive collapse mechanism very well in detail. Then, the development of deformation during the three phases is analyzed under different peak ground accelonations (PGA) and thus a new description of behavior level of spherical shell is set up with a damage assessment index based on relative displacement of gravity. All the work is useful for further study on the catastrophic mechanism of space structure under severe earthquake.