摘要：模拟非平稳随机过程已经成为工程中经常遇到的情况，使非平稳过程的大量模拟样本具有相同的统计特性并不容易。基于样本记录正交HHT变换的Hilbert谱提出了非平稳随机过程的模拟方法。首先，利用正交化方法对IMF分量进行处理，避免了传统EMD分解造成的能量泄漏。第二步，把样本的Hilbert谱均值作为随机过程的目标Hilbert谱，通过引入随机相位进行非平稳随机过程的仿真，并且给出了随机过程的统计特性函数。通过对低频地震动记录和高频地铁振动记录的模拟算例表明，模拟的非平稳过程样本与原记录在时频分布上非常接近，具有相同的统计特性。

Abstract: Simulation of nonstationary processes has become an indispensable tool in engineering. It is not easy for samples of nonstationary stochastic having same statistic characteristics. A new method is proposed for the simulation of nonstationary random processes based on orthogonal Hilbert-Huang transform (OHHT) spectra of their sample observations. Firstly, orthogonal method is introduced to treat with IMF, and the result shows that orthogonal HHT is a universal method avoiding leakage of energy compared with conventional HHT. Secondly, based on OHHT, the average of the Hilbert spectra over the samples is then defined as the Hilbert spectrum of the peocess and used as the target in the simulation of the process. The statistic characteristics fuction of stochastic process is given in the paper. Simulation of earthquake ground motion characteristic of low frequency and simulation of subwary vibration characteristic of high frequency are carried out in the paper. The time history of samples, Fourier amplitude spectrum of samples and response spectra of samples compare well with those of the records. Samples and record of same process have same statistic characteristics.