Analytical Method to Assess Dynamic Response of Tall Buildings to Downburst Windstorm

高层建筑和水平轴风力机等竖向结构容易受到风致振动和复杂风-结构相互作用的潜在破坏。近年来，由于美国和世界其他地区倾向于建造更高的建筑和更大直径的叶片风力涡轮机，这个问题的相关性吸引了工程研究人员。高层结构的设计通常基于恒定和平稳的风荷载条件。然而，风通常是暂时的，例如下击暴风，这是一种气象现象，会在地面附近引发破坏性的风荷载爆发。对瞬时风荷载的研究也是相关的，因为越来越多的结构被这类事件破坏。该项目致力于开发一种可行的计算方法，用于评估高层结构对下暴型风暴的动态响应。本项目将寻求一种新的分析方法来评估高层结构在瞬时风荷载作用下的随机动力响应。该方法将考虑系统的非线性和气动耦合效应。该方法将基于紧支撑小波和小波-Galerkin变换的概念，该变换能够通过在建模中保留时频特征来将微分方程组简化为代数形式。该研究将促进小波-伽辽金方法在求解风致耦合非线性随机动力问题中的应用。此外，该项目将在一系列高层结构的降阶模型上研究由瞬时下击暴流类风引起的动力学。例子包括两座基准高层建筑和一台大直径水平轴风力涡轮机。研究将通过对基准建筑的缩尺模型进行风洞实验来验证分析方法。计划开展综合外联活动，通过教育工具传播研究结果。

Vertical structures such as tall buildings and horizontal-axis wind turbines are prone to wind-induced vibrations and potential damage originating from complex wind-structure interaction. The relevance of this issue has attracted engineering researchers in recent years because of the tendency to erect taller buildings and larger-diameter-blade wind turbines in the United States and other parts of the World. The design of tall structures is usually based on steady and stationary wind load conditions. However, winds are often transient, such as in the case of a downburst storm, a meteorological phenomenon which induces an outburst of damaging wind loads near the ground. The study of transient wind loads is also relevant since increasing number of structures is damaged by this type of events. This project pursues to develop a viable computational method for the dynamic response assessment of tall structures against a downburst type of storm. This project will pursue a novel analytical method for assessing the stochastic dynamic response of tall structures due to transient wind loads. The method will account for system nonlinearity and aerodynamic coupling effects. The method will be based on the concepts of compactly supported wavelets and the Wavelet-Galerkin transform, which enables reducing a system of differential equations to an algebraic form by preserving time-frequency features in the modeling. The study will advance the utilization of Wavelet-Galerkin method for solving wind-induced coupled nonlinear stochastic dynamic problems. Moreover, the project will investigate the dynamics, caused by transient downburst-like winds, on a series of reduced-order models of tall structures. Examples will include two benchmark tall buildings and one large-diameter horizontal-axis wind turbine. The research will validate the analytical method by conducting wind tunnel experiments on scaled models of the benchmark buildings. Integrated outreach activities are planned to disseminate the findings of the study through educational tools.