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The Duffing equation (or Duffing oscillator), named after Georg Duffing, is a non-linear second-order differential equation used to model certain damped and driven oscillators. The equation is given by : where the (unknown) function ''x''=''x''(''t'') is the displacement at time ''t'', is the first derivative of ''x'' with respect to time, i.e. velocity, and is the second time-derivative of ''x'', i.e. acceleration. The numbers , , , and are given constants. The equation describes the motion of a damped oscillator with a more complicated potential than in simple harmonic motion (which corresponds to the case β=δ=0); in physical terms, it models, for example, a spring pendulum whose spring's stiffness does not exactly obey Hooke's law. The Duffing equation is an example of a dynamical system that exhibits chaotic behavior. Moreover, the Duffing system presents in the frequency response the jump resonance phenomenon that is a sort of frequency hysteresis behaviour. ==Parameters== * controls the size of the damping. * controls the size of the stiffness. * controls the amount of non-linearity in the restoring force. If , the Duffing equation describes a damped and driven simple harmonic oscillator. * controls the amplitude of the periodic driving force. If we have a system without driving force. * controls the frequency of the periodic driving force. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「Duffing equation」の詳細全文を読む スポンサード リンク
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