单层网壳结构初始几何缺陷场模拟方法研究进展

Research Progress on Simulation Methods of Initial Geometric Imperfection Fields of Single-Layer Gridshells

单层网壳结构的安全性很大程度上取决于其稳定承载力,而其制作及安装过程中产生的节点几何偏差初始缺陷对其稳定承载力具有重大影响。对单层网壳结构初始几何缺陷场模拟方法的研究进展和现行规范的规定进行了系统综述和分析,结果表明既有的随机性模拟法、确定性模拟法和半随机性模拟法均存在一定问题,规范所推荐的初始缺陷模拟方法脱离实际,因而无法准确确定单层网壳结构稳定承载力的真实概率模型。因此,亟待提出一种考虑结构拓扑约束、基本假定合理、计算成本可控的初始几何缺陷场模拟方法,为完善单层网壳结构整体稳定分析方法提供科学依据,并为分析其稳定可靠度提供理论基础。

The safety of single-layer gridshells depends largely on their buckling capacity,on which the initial geometric imperfections of joint deviations generated during the installation of the structure have a significant impact.This paper reviews the existing simulation methods on the initial geometric imperfection field of single-layer gridshells and specifications in current codes.The results show that existing stochastic,deterministic,and semi-stochastic simulation methods are all with deficiencies,and it is impossible to determine the real probability model of the buckling capacity of single-layer gridshells;besides,the initial imperfection simulated by current codes is unrealistic.Therefore,it is urgent to propose a simulation method for the initial geometric imperfection field that considers the structural topological constraints,with reasonable basic assumptions and controllable computational costs,providing a scientific basis for the improvement of the global stability analysis method for single-layer gridshells and a theoretical foundation for the analysis of their stability reliability.