3 research outputs found
Higher-order approximation of cubicâquintic duffing model
We apply an Artificial Parameter Lindstedt-PoincarĂ© Method (APL-PM) to find improved approximate solutions for strongly nonlinear Duffing oscillators with cubicâquintic nonlinear restoring force. This approach yields simple linear algebraic equations instead of nonlinear algebraic equations without analytical solution which makes it a unique solution. It is demonstrated that this method works very well for the whole range of parameters in the case of the cubic-quintic oscillator, and excellent agreement of the approximate frequencies with the exact one has been observed and discussed. Moreover, it is not limited to the small parameter such as in the classical perturbation method. Interestingly, This study revealed that the relative error percentage in the second-order approximate analytical period is less than 0.042% for the whole parameter values. In addition, we compared this analytical solution with the Newtonâ Harmonic Balancing Approach. Results indicate that this technique is very effective and convenient for solving conservative truly nonlinear oscillatory systems. Utter simplicity of the solution procedure confirms that this method can be easily extended to other kinds of nonlinear evolution equations
Higher-order approximation of cubicâquintic duffing model
We apply an Artificial Parameter Lindstedt-PoincarĂ© Method (APL-PM) to find improved approximate solutions for strongly nonlinear Duffing oscillators with cubicâquintic nonlinear restoring force. This approach yields simple linear algebraic equations instead of nonlinear algebraic equations without analytical solution which makes it a unique solution. It is demonstrated that this method works very well for the whole range of parameters in the case of the cubic-quintic oscillator, and excellent agreement of the approximate frequencies with the exact one has been observed and discussed. Moreover, it is not limited to the small parameter such as in the classical perturbation method. Interestingly, This study revealed that the relative error percentage in the second-order approximate analytical period is less than 0.042% for the whole parameter values. In addition, we compared this analytical solution with the Newtonâ Harmonic Balancing Approach. Results indicate that this technique is very effective and convenient for solving conservative truly nonlinear oscillatory systems. Utter simplicity of the solution procedure confirms that this method can be easily extended to other kinds of nonlinear evolution equations
Exact solution for the unforced Duffing oscillator with cubic and quintic nonlinearities
The nonlinear differential equation governing the periodic motion of the one-dimensional, undamped, unforced cubicâquintic Duffing oscillator is solved exactly, providing exact expressions for the period and the solution. The period is given in terms of the complete elliptic integral of the first kind and the solution involves Jacobi elliptic functions. Some particular cases obtained varying the parameters that characterize this oscillator are presented and discussed. The behaviour of the period as a function of the initial amplitude is analysed, the exact solutions and velocities for several values of the initial amplitude are plotted, and the Fourier series expansions for the exact solutions are also obtained. All this allows us to conclude that the quintic term appearing in the cubicâquintic Duffing equation makes this nonlinear oscillator not only more complex but also more interesting to study.This work was supported by the âGeneralitat Valencianaâ of Spain, under project PROMETEOII/2015/015, and by the âVicerrectorado de TecnologiÌas de la InformacioÌnâ of the University of Alicante, Spain, under project GITE-09006-UA