periodic solutions of the duffing harmonic oscillator by he’s energy balance method

Duffing harmonic oscillator is a common model for nonlinear phenomena in science and engineering. this paper presents he´s energy balance method (ebm) for solving nonlinear differential equations. two strong nonlinear cases have been studied analytically. analytical results of the ebm are compared with the solutions obtained by using he´s frequency amplitude formulation (faf) and numerical solutions using rungekutta method. the results show the presented method is potentially to solve high nonlinear oscillator equations.