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以高层钢框架预应力索支撑结构为例,研究了应用AR模型进行脉动风模拟时,模型的2个关键参数——时间步长、时域点数的取值对模拟结果的影响。在讨论基于AR模型的脉动风模拟方法的基础上,利用有限元软件Sap2000建立结构模型,利用Matlab编制AR算法程序,分别选用不同的时间步长、时域点数对结构进行脉动风速时程分析,将生成的脉动风速功率谱曲线与目标谱进行对比,根据曲线吻合情况确定参数的合理取值范围。结果表明,时间步长的取值对AR模型模拟结果有较大影响,其最优值域为0.10~0.18 s,超出这一范围均会导致功率谱曲线与目标谱偏离,降低模拟精度;时域点数对AR模型模拟精度的影响较小,可根据工程需要选择时域点数。
Taking the high-rise steel frame prestressed cable support structure as an example, the influence of the two key parameters of the model, the time step and the number of time points, on the simulation results was studied when the AR model was used for pulsating wind simulation. After discussing the turbulent wind simulation method based on AR model, the finite element software Sap2000 was used to establish the structural model, and Matlab was used to compile the AR algorithm program. Different time steps and time domain points were used to analyze the fluctuating wind speed time history of the structure. The generated fluctuating wind speed power spectrum curve is compared with the target spectrum, and a reasonable range of parameters is determined according to the matching of the curves. The results show that the value of time step has a great influence on the simulation results of AR model, and the optimal range is 0.10~0.18 s. Exceeding this range will cause the deviation of the power spectrum curve from the target spectrum and reduce the simulation accuracy; The number of domain points has little effect on the accuracy of AR model simulation, and the number of time domain points can be selected according to the needs of the project.