基于ARMA模型模拟高架桥的脉动风速时程

Simulation of fluctuating wind speed time series applied onoverpass bridges with resorting to ARMA model

强风是高架桥设计与防灾减灾分析的控制性荷载之一。风与高架桥相互作用十分复杂,可以通过风洞试验、现场实测、数值模拟获取可靠的风速(风荷载)数据。尽管如此,时域分析可以使人们更全面地了解高架桥的风振响应特性,也能更直观地反映高架桥风致振动控制的有效性。因此,使用线性滤波法即白噪声滤波法(WNFM)中的自回归滑动平均(ARMA)模型模拟高架桥的脉动风速时程。首先,考虑高架桥脉动风速的时间和空间相关性,导出自回归(AR)模型阶数与滑动回归(MA)模型阶数不相等时ARMA模型的表达式。接着,基于Kaimal风速谱,使用ARMA模型来模拟一座实际高架桥的脉动风速时程。最后,通过比较模拟风速功率谱、自相关和互相关函数与目标风速功率谱、自相关和互相关函数的吻合程度,验证基于ARMA模型模拟高架桥脉动风速时程的可行性。

The main objective of the paper is to simulate the fluctuating wind velocity time series applied on overpass bridges with resorting to the auto-regressive moving average (ARMA) model in the white noise filtration method (WNFM). Taking into account both the time and space correlativity of the wind speed, the expressions of the ARMA model were derived with the unequal orders of auto-regressive (AR) and moving-regressive (MA) components. Then, based on Kaimal spectrum, the simulation of the wind velocity time histories on a real overpass bridge was carried out utilizing the ARMA model. Through comparing the simulated values of wind speed spectral density, auto-and cross-correlation functions with the corresponding target values, the feasibility of the method proposed was corroborated.