Schwebungen schwach gekoppelter nichtlinearer Systeme

Expressions for the slowly varying amplitudes and phase-difference of two undamped non-linear mechanical or electrical systems with weak coupling are developed and discussed. The method employed is the Kryloff-Bogoljuboff-approximation, according to which the differential equations of the second order for the oscillating quantities are replaced by differential equations of the first order for the amplitudes and the phase-difference. The results are in some cases compared with the results of a Runge-Kutta numerical integration by electronic digital computer.