带腐蚀损伤的螺栓球网壳结构极限承载性能研究

The durability of the reticulated shells is poor in a highly corrosive environment. With the increase in service time, the aggravation of corrosion at joints will lead to the decrease of the ultimate bearing capacity of the reticulated shells, and finally the overall failure of the structures. It has already been recorded that a certain large dome collapsed due to heavy corrosion and caused a huge loss. However, at present, the studies on the corrosion failure of reticulated shells are limited both at home and abroad. Therefore a pioneering study of the ultimate bearing capacity of reticulated shells with corrosion damage is of great significance. Based on our previous research, the bearing capacity tests of bolted ball joints with corrosion damage are performed in a further study. Combining these experiments with the refined numerical simulations, the decrease of bearing capacity and the degradation of the stiffness of the corroded bolted ball joints are clarified, and a model describing the rules of structural performance of bolted ball joints with corrosion damage is developed and justified. With the incorporation of the corrosion damage model of bolted ball joints, the bearing capacity analysis and simulation study of the whole structure are conducted to reveal the time-dependent rule of the ultimate bearing capacity, failure mode and failure propagation path of the in-service reticulated shells. As the implication of proposed research, reasonable and effective early warning methods for the progressive failure can be provided to avoid the sudden collapse of the reticulated shells in the corrosive environment.

在高腐蚀环境下，网壳结构的耐久性较差，随着服役时间增长和腐蚀加剧，节点的腐蚀将导致网壳结构极限承载力下降，最终导致结构的整体破坏。已有大型网壳结构因腐蚀而倒塌造成巨大损失的实例。目前国内外的相关研究较少，因此，对带腐蚀损伤的网壳结构极限承载性能开展研究具有重要意义。本课题在以往研究的基础上，进一步开展带腐蚀损伤的螺栓球节点的承载性能试验研究，结合精细数值模拟，阐明腐蚀后螺栓球节点的承载力下降和刚度退化的规律，建立合理的螺栓球节点的腐蚀损伤分析模型，基于该腐蚀损伤模型进行整体结构承载力分析和模拟研究，揭示在役网壳极限承载力、破坏模式和破坏传播路径的时变规律，为腐蚀环境下网壳破坏提供合理、有效的预警方法，避免结构突然倒塌的灾难性事故发生。

在高腐蚀环境下，网壳结构的耐久性较差，随着结构服役时间增长和腐蚀加剧，节点的的腐蚀将导致网壳极限承载力下降，最终导致结构的整体破坏。本课题以螺栓球节点的承载性能为对象，以极限承力降低和刚度退化作为描述节点腐蚀后性能劣化的载体，首次对带腐蚀损伤的螺栓球节点进行静力抗拉试验，并提出节点刚度退化规律和承载力退化规律，结合精细化数值模型，综合提出合理的、时变的螺栓球节点腐蚀损伤模型。本课题从试验、数值模拟和理论方法三个角度进行研究，首先开展带腐蚀损伤的螺栓球节点的承载性能试验研究，结合精细数值模拟，综合建立螺栓球节点的腐蚀损伤分析模型，将该模型导入到结构数值模型并进行整体结构承载力分析。由于该思路第一次用在研究带腐蚀损伤的网壳结构承载性能分析上，故本领域具有思路上的创新性。.另外，从学科上看，钢材的腐蚀损伤属于化学和材料科学，而网壳结构极限承载性能则是属于结构力学的范畴，故本课题是通过多学科交叉尝试建立一种新的科研途径。