铝合金单层网壳中新型装配式节点承载性能及结构倒塌破坏机理研究

Aluminum single-layer latticed shells have the advantages of light weight, good corrosion resistance and excellent mechanical properties, which could well satisfy the requirements of complex architectural form. At present the number of existing aluminum shells is relatively few. The main reason lies in lack of knowledge of material properties, design methods and mechanical properties, as well as shortage of joint types and high construction costs, which restrict the further application of aluminum single-layer latticed shells. This project proposes an assembly-type hollow hub joint used in aluminum single-layer latticed shells. Based on the joint bearing performance test, hysteretic test, as well as theoretical and numerical analysis, the force transmission mechanism and failure mode of the new assembly-type joint under axial force, bending moment and complex stress state will be revealed. The formulas of bearing capacity, initial axial stiffness and initial rotation stiffness will be proposed. Based on the mechanical model considering the stiffness characteristics of the new assembly-type joint, the refined analysis on the overall structure and stability test on the scale model will be carried out. The reduction factor of stability bearing capacity and the redundancy evaluation index based on the stiffness of joints will be presented to analyze the stability performance and collapse mechanism of aluminum single-layer latticed shells. The purpose of this project is to provide theoretical and technical guidance for the popularization and application of the new assembly-type joint and the aluminum single-layer latticed shells.

铝合金单层网壳结构具有自重轻、耐腐蚀性好、机械加工性能优良等优点，可以很好地满足复杂建筑造型的要求。目前已建成的铝合金网壳数量较少，设计施工人员对铝合金结构的材料特性、设计方法和力学特性等认识不足，同时节点形式单一、工程造价相对较高，使其进一步推广应用受到制约。本项目提出一种适用于铝合金单层网壳的装配式空心毂节点，结合节点承载性能试验、滞回试验、理论及数值分析等，揭示新型装配式节点在轴力、弯矩及复杂受力状态下的传力机理和破坏模式；提出节点承载力、初始轴向刚度、初始转动刚度计算公式；建立考虑新型装配式节点刚度特性的机械模型进行整体结构精细化分析，并结合缩尺模型稳定性试验，提出铝合金单层网壳稳定承载力折减系数和基于节点刚度的冗余度评价指标，分析铝合金单层网壳稳定性及倒塌破坏机理。通过以上研究，为新型装配式节点及铝合金单层网壳的进一步推广应用提供理论及技术指导。

提出了一种适用于铝合金单层网壳的装配式空心毂节点。结合理论分析、数值模拟及足尺试验，揭示了新型铝合金节点在轴力、弯矩、偏心荷载及平面外往复荷载作用下的传力机理和破坏模式。基于组件法，推导了新型装配式空心毂节点轴向承载力、抗弯承载力、初始轴向刚度及初始转动刚度的理论计算公式，通过足尺试验和参数化数值模拟对上述公式进行了验证，并拟合得到了新型节点承载力实用计算公式。同时，基于节点承载性能分析结果，通过等效短梁模型模拟节点的各向刚度及承载力，考察了节点刚度特性对铝合金单层网壳稳定承载力影响。通过参数化数值分析，研究了跨度、矢跨比、网格形式等对铝合金单层网壳稳定承载力的影响规律，确定了装配式空心毂节点铝合金网壳稳定承载力折减系数的取值范围。考虑了流-固耦合效应、节点刚度变化等因素的影响，基于CFD数值模拟方法对铝合金单层网壳进行了风振响应分析。基于连续倒塌临界荷载、临界位移及应变能等指标，评估了常见网格形式铝合金网壳的抗连续倒塌性能。