Abstract This study presents a new approach for identification of nonlinear aerodynamic damping of wind-excited flexible structures from stochastic response time history that can be modeled as the output of a single-degree-of-freedom system under a white noise excitation. The amplitude-dependent aerodynamic damping ratio is described as a polynomial function of vibration displacement or velocity. Based on the equivalent nonlinear equation approach, the probability density function (PDF) of displacement can be given in terms of damping model parameters, which generally follows a hardening non-Gaussian distribution. It is proposed to identify the damping model parameters by curve-fitting displacement PDF determined from the response data using a nonlinear least-square optimization technique. Firstly, the stochastic response of a tall building with a known nonlinear aerodynamic model is simulated and the performance of the proposed approach is investigated. This method is then applied to a square-shaped tall building model and a bridge deck section using wind tunnel measured data. Finally, it is used for a traffic-signal-support structure using field measurement response data. The results are also compared with those from other existing approaches. The proposed approach permits determination of nonlinear aerodynamic damping from single stochastic response history and is very easy to use in practice.

中文翻译：

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曲线拟合非高斯响应概率密度函数识别风激柔性结构非线性气动阻尼

摘要 本研究提出了一种从随机响应时程识别风激柔性结构非线性气动阻尼的新方法，该方法可以建模为白噪声激励下单自由度系统的输出。与振幅相关的气动阻尼比被描述为振动位移或速度的多项式函数。基于等效非线性方程方法，可以根据阻尼模型参数给出位移的概率密度函数（PDF），其通常遵循硬化非高斯分布。建议通过使用非线性最小二乘优化技术从响应数据确定的曲线拟合位移 PDF 来识别阻尼模型参数。首先，模拟了具有已知非线性空气动力学模型的高层建筑的随机响应，并研究了所提出方法的性能。然后将该方法应用于使用风洞测量数据的方形高层建筑模型和桥面板截面。最后，它用于使用现场测量响应数据的交通信号支持结构。结果还与其他现有方法的结果进行了比较。所提出的方法允许从单个随机响应历史中确定非线性气动阻尼，并且在实践中非常容易使用。它用于使用现场测量响应数据的交通信号支持结构。结果还与其他现有方法的结果进行了比较。所提出的方法允许从单个随机响应历史中确定非线性气动阻尼，并且在实践中非常容易使用。它用于使用现场测量响应数据的交通信号支持结构。结果还与其他现有方法的结果进行了比较。所提出的方法允许从单个随机响应历史中确定非线性气动阻尼，并且在实践中非常容易使用。