Damage and Instability Detection of Civil Large-scale Space Structures Under Operational and Multi-hazard Environments based on Change in Macro-geometrical Patterns/Shapes

体育场馆、竞技场和礼堂等土木建筑通常是为数百甚至数千人聚集的场所而建造的。这种结构的屋顶圆顶可能倒塌，可能危及许多人的生命。本研究的重点是大型圆顶结构健康自动监测系统，该系统可以为结构失稳或结构构件损坏导致的倒塌提供早期预警。预警有助作出维修或拆卸楼宇的决定，令公众及业主都能无忧无忧。该系统可用于保护历史建筑（如大教堂），验证圆顶结构修复的适当性，以及在地震或强风事件后评估这些结构的健康状况。这项研究的目的是开发创新而实用的方法来检测在操作或多灾害环境下空间结构的损坏和不稳定性。本文将通过三个方面的研究工作来实现研究目标：1)利用分形几何理论建立基于构件形态分形状态的损伤检测方法；2)开发不同的方法来检测不稳定，包括单个构件屈曲，节点断裂不稳定或动态不稳定；3)通过无线传感器网络与多度量测量（倾角、应变和/或加速度）集成这些方法，形成结构健康监测系统。目标是实现损坏、不稳定和潜在崩溃的自动预警。虽然投影方法对结构的形状/图案变化有效，但不需要直接测量位移。形状/图案的变化战略性地反映在倾斜角度，应变和加速度，这可以很容易地测量。这些方法也不需要基线反应数据。所开发的结构健康监测系统能够检测失稳，并能在多种危险环境下工作。

Civil structures such as sports stadiums, arenas and auditoriums are usually built for venues where hundreds or even thousands of people assemble. A possible collapse of roof dome of this type of structure may risk many lives. This research focuses on an automatic structural health monitoring system for large domes that can provide early warning of structural problems from instability or damage to structural members resulting in collapse. Early warning can facilitate decision-making on repair or demolition, leading to worry-free structures for both the general public and the owners. The system has potential use to protect historical structures (e.g., cathedrals), to verify the appropriateness of repairs of dome structures, and to evaluate the health condition of these structures after an earthquake or a strong wind event. The objective of this research is to develop innovative yet practical approaches to detect damage and instability in space structures under operational or multi-hazard environments. This research objective will be achieved through three research tasks: 1) develop an approach to detect damage based on the status of fractal patterns of structural member configuration using fractal geometry; 2) develop different approaches to detect instabilities, including individual members buckling, nodal snap-through instability or dynamic instability; and 3) integrate these approaches through a wireless sensor network with multi-metric measurements (tilt angles, strains and/or accelerations) to form a structural health monitoring system. The goal is to achieve automatic early-warning of damage, instability and potential collapse. Although projected approaches work on the shape/pattern changes of the structure, no direct displacement measurements will be required. The shape/pattern changes are strategically reflected in tilt angles, strains and accelerations, which can be measured easily. These approaches also do not require baseline response data. The developed structural health monitoring system can detect instability and can work under multi-hazard environments.