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Journal of Zhejiang University SCIENCE A
ISSN 1673-565X(Print), 1862-1775(Online), Monthly
2017 Vol.18 No.9 P.704-717
Stochastic averaging of quasi partially integrable Hamiltonian systems under fractional Gaussian noise
Abstract: A stochastic averaging method for predicting the response of quasi partially integrable and non-resonant Hamiltonian systems to fractional Gaussian noise (fGn) with the Hurst index 1/2<H<1 is proposed. The averaged stochastic differential equations (SDEs) for the first integrals of the associated Hamiltonian system are derived. The dimension of averaged SDEs is less than that of the original system. The stationary probability density and statistics of the original system are obtained approximately from solving the averaged SDEs numerically. Two systems are worked out to illustrate the proposed stochastic averaging method. It is shown that the results obtained by using the proposed stochastic averaging method and those from digital simulation of original system agree well, and the computational time for the former results is less than that for the latter ones.
Key words: Fractional Brownian motion (fBm); Fractional Gaussian noise (fGn); Quasi partially integrable Hamiltonian system; Stochastic averaging method; Stationary response
创新点:现有文献中,对于分数阶高斯噪声激励下动态系统响应的研究,多为单自由度或二自由度线性系统,而本文的方法针对的是多自由度强非线性系统,可预测分数阶高斯噪声激励下的多自由度强非线性系统的稳态响应。
方法:1. 根据分数阶布朗运动的顺式积分原理及其随机微分规则,将分数阶高斯噪声激励下的多自由度强非线性系统模型化为分数阶高斯噪声激励下的拟部分可积哈密顿系统。2. 运用随机平均原理进行降维,得到维数更低的分数阶随机微分方程组,由此,原系统可被这组方程近似代替。3. 运用数值方法求解分数阶随机微分方程组,得到原系统的近似稳态响应。
结论:1. 从平均后的分数阶随机微分方程组模拟得到的近似稳态响应与原系统方程模拟得到的稳态响应吻合度较高,说明了此方法的有效性。2. 模拟平均后的分数阶随机微分方程组的时间比模拟原系统方程的时间短很多,说明此方法效率高。
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DOI:
10.1631/jzus.A1600541
CLC number:
O32
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On-line Access:
2024-08-27
Received:
2023-10-17
Revision Accepted:
2024-05-08
Crosschecked:
2017-08-15