Collaborative Research: Downburst Fragility Characterization of Transmission Line Systems Using Experimental and Validated Stochastic Numerical Simulations

合作研究：使用实验和验证的随机数值模拟来表征传输线系统的下击暴脆性

• 批准号: 1762968
• 负责人: Amal Elawady
• 金额: $ 30.78万
• 依托单位: Florida International University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1762968&HistoricalAwards=false
• 关键词: Collaborative; Research; Downburst; Fragility; Characterization

Downbursts, referring to downward high intensity winds associated with thunderstorms, pose a major threat to power transmission grids in many parts of the United States. Considering the distributed size of the power transmission infrastructure, significant investments will be needed in order to upgrade the existing systems and properly design new infrastructure to resist downburst wind forces. The goal of this research is to develop an integrative experimental and numerical framework that is capable of characterizing the extent of vulnerability of the power transmission infrastructure against downbursts, and identify the most critical components. The framework will provide knowledge that can help reduce outage-induced societal disruptions caused by downbursts, and thus enable continued national prosperity and welfare following a downburst event. Using this framework, various significant factors for the downburst performance of transmission systems and potential causes of past failures will be investigated. Moreover, this research will develop the first generation of downburst fragility models for transmission tower-line systems (TLSs) using experimentally validated numerical models. These fragility models are crucial for risk-informed decision making for design and management of the transmission grid in order to mitigate future failures and enhance the resiliency of the grid against extreme weather events. The numerical and experimental studies will provide the knowledge needed to enhance design methodologies to include downburst wind loads for transmission line systems. The research findings will be integrated into undergraduate and graduate courses at Florida International University (FIU) and The Ohio State University to better prepare the future generation of infrastructure engineers. Project data will be archived and publicly shared in the NSF-supported Natural Hazards Engineering Research Infrastructure (NHERI) Data Depot (https://www.DesignSafe-ci.org/). This research will develop an integrative experimental and numerical framework to characterize the fragility of transmission line systems against downbursts. The experimental research will involve developing a versatile downburst simulator at the NSF-supported NHERI Wall of Wind (WOW) Experimental Facility (EF) at FIU. Using this simulator, a scaled, aeroelastic multi-span TLS will be tested; the results will be used to experimentally validate high-fidelity finite element models of coupled transmission tower-insulator-conductor-foundation systems. Through these experimental and numerical investigations, new knowledge will be gained with regard to the aerodynamic behavior of conductors and drag and shielding effects on lattice tower sections under non-synoptic downburst wind fields. Moreover, these investigations will reveal extreme nonlinear behaviors of transmission line systems in post-elastic regimes when towers are damaged or conductors fail. The research also will provide new physics-based insights into the role of uncertainties in the downburst performance of TLSs. Failure modes that are unique to or are more likely to occur under non-synoptic downburst loadings, as compared to those under synoptic hurricane loadings, will be identified and characterized. The produced data and models will be integrated to develop the first generation of multi-dimensional demand and fragility surfaces for TLSs under downbursts at component- and system-levels using highly efficient and accurate machine learning techniques. In addition, the experimental downburst simulator at the NHERI WOW EF at FIU will provide the natural hazards community with a unique testbed with dual simulation capabilities to generate both non-synoptic and synoptic winds and analyze the impacts on buildings and other structural systems.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

下击暴流是指与雷暴相关的向下高强度风，对美国许多地区的输电网构成重大威胁。 考虑到输电基础设施的分布式规模，需要大量投资来升级现有系统并正确设计新的基础设施以抵御下击暴流风力。这项研究的目标是开发一个综合实验和数值框架，能够表征输电基础设施对抗下击暴流的脆弱程度，并确定最关键的组件。该框架将提供有助于减少下击暴流造成的停电引起的社会破坏的知识，从而在下击暴流事件后实现国家的持续繁荣和福利。使用该框架，将研究传输系统下击暴流性能的各种重要因素以及过去故障的潜在原因。此外，这项研究将使用经过实验验证的数值模型开发第一代输电塔线系统（TLS）的下击暴流脆弱性模型。这些脆弱性模型对于输电网设计和管理的风险知情决策至关重要，以减轻未来的故障并增强电网应对极端天气事件的弹性。数值和实验研究将提供增强设计方法所需的知识，包括输电线路系统的下击暴流风荷载。 研究结果将被纳入佛罗里达国际大学 (FIU) 和俄亥俄州立大学的本科生和研究生课程中，以更好地培养下一代基础设施工程师。项目数据将在 NSF 支持的自然灾害工程研究基础设施 (NHERI) 数据仓库 (https://www.DesignSafe-ci.org/) 中存档并公开共享。这项研究将开发一个综合实验和数值框架来表征输电线路系统对抗下击暴流的脆弱性。实验研究将涉及在 NSF 支持的 FIU 的 NHERI 风墙 (WOW) 实验设施 (EF) 中开发多功能下击暴流模拟器。使用该模拟器，将测试按比例缩放的气动弹性多跨距 TLS；结果将用于实验验证耦合输电塔-绝缘体-导体-基础系统的高保真有限元模型。通过这些实验和数值研究，将获得关于非天气下击暴流风场下导体的空气动力学行为以及格构塔截面的阻力和屏蔽效应的新知识。此外，这些研究将揭示当塔损坏或导体失效时，后弹性状态下输电线路系统的极端非线性行为。该研究还将提供基于物理的新见解，以了解不确定性在 TLS 下击暴性能中的作用。与天气飓风载荷下相比，非天气下击暴载荷下特有的或更有可能发生的失效模式将被识别和表征。生成的数据和模型将被集成，以使用高效和准确的机器学习技术，在组件和系统级别开发第一代 TLS 多维需求和脆弱性表面。此外，佛罗里达国际大学 NHERI WOW EF 的实验性下击暴流模拟器将为自然灾害社区提供具有双重模拟功能的独特测试台，以生成非天气风和天气风，并分析对建筑物和其他结构系统的影响。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Aeroelastic testing to examine the dynamic behaviour of a single self-supported electrical transmission tower subjected to downburst wind loads

气动弹性测试，用于检查单个自承式输电塔在下击暴流风载荷作用下的动态行为

• 发表时间: 2022-07
• 期刊: Fourteenth Americas Conference on Wind Engineering
• 作者: Alawode; K. J
• 通讯作者: K. J

Use of Optimization Technique for Design of Scaled Aeroelastic Model for Wind Tunnel Testing

利用优化技术设计风洞试验缩放气动弹性模型

• 发表时间: 2023-08
• 期刊: 16th International Conference on Wind Engineering (ICWE
• 作者: Metwally; O.
• 通讯作者: O.

Dynamic properties of an aeroelastic transmission tower subjected to synoptic and downburst-like outflows

受天气和下击暴流影响的气动弹性输电塔的动态特性

• DOI: 10.1016/j.jweia.2023.105557
• 发表时间: 2023-11-01
• 期刊: Journal of Wind Engineering and Industrial Aerodynamics
• 影响因子: 4.8
• 作者: Kehinde J. Alawode;Ziad Azzi;A. Elawady;A. Chowdhury
• 通讯作者: A. Chowdhury

Aerodynamics of low-rise buildings subjected to downburst wind loads

下击暴流风荷载作用下低层建筑的空气动力学

• 发表时间: 2022-07
• 期刊: Fourteenth Americas Conference on Wind Engineering
• 作者: Mejia; A.
• 通讯作者: A.

Examination of different wall jet and impinging jet concepts to produce large-scale downburst outflow

检查不同的壁射流和冲击射流概念以产生大规模的下击暴流

• DOI: 10.3389/fbuil.2022.980617
• 发表时间: 2022-09-27
• 期刊: Journal of Wind Engineering and Industrial Aerodynamics
• 影响因子: 4.8
• 作者: Alvaro Danilo Mejia;A. Elawady;Krishna Sai Vutukuru;Dejiang Chen;A. Chowdhury
• 通讯作者: A. Chowdhury