AN ANALYSIS OF THE FORCED OSCILLATIONS OF A SYSTEM WITH PERIODICALLY CHANGING COEFFICIENTS,

摘要

The report investigates the influence of the periodic parameter change of a linear system with one degree of freedom on forced oscillations in a case when the basic interval of instability is its dominant mode, i.e.,when the period of parameter change is equal to half the excitation force. If the linear resistance is insufficient,the natural oscillations will be unstable at a certain interval of the external frequency,and at the boundaries of this interval the amplitude of the external frequencies exceeds all limits. In case the linear resistance of the system is sufficient for suppressing the interval of unstable natural oscillations,the forced oscillations are limited. But the maximum amplitude strongly depends on the phase angle of the excitation force. For a smaller phase angle interval it can even be that the maximum amplitude will be less than for the case corresponding to a similar system with constant coefficients and resistance. (Author)