Analytical solutions of periodic motions in 1-dimensional nonlinear systems

In this paper, analytical solutions of periodic motions in a 1-D nonlinear dynamical system are obtained through the generalized harmonic balance method with prescribed-computational accuracy. From this method, the 1-D dynamical system is transformed to a nonlinear dynamical system of coefficients in the Fourier series. The analytical solutions of periodic motions are obtained by equilibriums of the coefficient dynamical systems, and the corresponding stability and bifurcations of periodic motions are completed via the eigenvalue analysis. The frequency-amplitude characteristics of periodic motions are analyzed through the different order harmonic terms in the Fourier series, and the corresponding quantity levels of harmonic amplitudes are determined. From such frequency-amplitude characteristics, the nonlinearity, singularity and complexity of periodic motions in the 1-D nonlinear systems can be discussed. Displacements and trajectories of periodic motions are illustrated for a better understanding of periodic motions in the 1-D nonlinear dynamical systems. From this study, the periodic motions in the 1-dimensional dynamical systems possess similar behaviors of periodic motions in the van der Pol oscillator.