为了研究宽带噪声激励下含分数阶导数的van der Pol-Duffing振子的首次穿越问题,首先应用广义谐波平衡技术,将分数阶导数表示的回复力分解为等效拟线性阻尼力和拟线性回复力,获得不含分数阶导数的等效非线性随机系统;然后,应用随机平均...为了研究宽带噪声激励下含分数阶导数的van der Pol-Duffing振子的首次穿越问题,首先应用广义谐波平衡技术,将分数阶导数表示的回复力分解为等效拟线性阻尼力和拟线性回复力,获得不含分数阶导数的等效非线性随机系统;然后,应用随机平均法将等效非线性随机系统近似为一维扩散过程,再建立和求解相应的后向Kolmogorov方程,获得系统的条件可靠性函数和平均首次穿越时间计算式;最后,通过实验结果表明,所提方法与蒙特卡罗法模拟结果吻合得非常好;系统的可靠性随分数阶数的增加而提高;分数阶导数表示的回复力不能简单地当作一类特殊的阻尼力.展开更多
The stochastic stability of the harmonically and randomly excited Duffing oscillator with damping modeled by a fractional derivative of Caputo's definition is analyzed.First,the system state is approximately descr...The stochastic stability of the harmonically and randomly excited Duffing oscillator with damping modeled by a fractional derivative of Caputo's definition is analyzed.First,the system state is approximately described by It equations through the stochastic averaging method based on the generalized harmonic function.Then,the associated expression for the largest Lyapunov exponent of the linearized averaged It is derived,and the necessary and sufficient condition for the asymptotic stability with probability one of the trivial solution of the original system is obtained approximately by letting the largest Lyapunov exponent be negative.The effects of fractional orders and random excitation intensities on the asymptotic stability with probability one determined by the largest Lyapunov exponent are shown graphically.展开更多
文摘为了研究宽带噪声激励下含分数阶导数的van der Pol-Duffing振子的首次穿越问题,首先应用广义谐波平衡技术,将分数阶导数表示的回复力分解为等效拟线性阻尼力和拟线性回复力,获得不含分数阶导数的等效非线性随机系统;然后,应用随机平均法将等效非线性随机系统近似为一维扩散过程,再建立和求解相应的后向Kolmogorov方程,获得系统的条件可靠性函数和平均首次穿越时间计算式;最后,通过实验结果表明,所提方法与蒙特卡罗法模拟结果吻合得非常好;系统的可靠性随分数阶数的增加而提高;分数阶导数表示的回复力不能简单地当作一类特殊的阻尼力.
基金supported by the National Natural Science Foundation of China(Grant Nos.10932009,11072212 and 11002059)the Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20103501120003)+2 种基金the Natural Science Foundation of Fujian Province (Grant No.2010J05006)the Fundamental Research Funds for Huaqiao University(Grant No.JB-SJ1010)the Research & Development Start Funds of Huaqiao University(Grant No.09BS622)
文摘The stochastic stability of the harmonically and randomly excited Duffing oscillator with damping modeled by a fractional derivative of Caputo's definition is analyzed.First,the system state is approximately described by It equations through the stochastic averaging method based on the generalized harmonic function.Then,the associated expression for the largest Lyapunov exponent of the linearized averaged It is derived,and the necessary and sufficient condition for the asymptotic stability with probability one of the trivial solution of the original system is obtained approximately by letting the largest Lyapunov exponent be negative.The effects of fractional orders and random excitation intensities on the asymptotic stability with probability one determined by the largest Lyapunov exponent are shown graphically.
