基于正交小波逆变换的平稳风速时程数值模拟

对于大型结构,风荷载往往起控制甚至决定作用,对其进行风振响应时域分析是必要的,而进行时域分析首先必须解决风荷载的输入问题.基于多分辨率分析的思想和正交小波基推导了小波系数与功率谱密度函数之间的关系,从而可由已知的功率谱密度函数随机生成各尺度上的小波系数,进而由生成的小波系数通过逆变换生成平稳风速时程.根据这一思路,利用L-P小波基,模拟了与Davenport谱相一致的某点脉动风速时程,算例表明,模拟的风速时程功率谱与给定的目标谱吻合较好,证明了该方法的有效性.

Numerical Simulation of Wind Velocity History on the Basis of Orthogonal Inverse Wavelet Transform

Wind load is one of the major even decisive factors to large-structure for which the time domain analysis of wind-induced dynamic response is required.The problem how to input the wind load is therefore to be solved first.According to the idea of multi-resolution analysis and orthonormal wavelets,relationship between wavelet coefficients and PSD(power spectral density) function is deduced,then the wavelet coefficients on each and every scale are obtained from the given PSD function.As a result,the inverse wavelet transform is applied to generating stationary wind velocity history through the given wavelet coefficients.In this way the L-P wavelet is applied to simulating the pulsate wind velocity history at a certain point,which conforms to Davenport power spectral density.A numerical example shows that the simulated PSD is consistent with the prescribed one and the method is valid.