ABSTRACT
Annotation. The phenomenon of parametric resonance in a rigid planar pendulum
caused by a square-wave modulation of its length is investigated both analytically
and with the help of a computer simulation. Characteristics of parametric reso-
nance are found and discussed in detail. The role of nonlinear properties of the
pendulum in restricting the resonant swinging is emphasized. The boundaries of
parametric excitation as functions of the modulation depth and the quality factor
are determined. Stationary oscillations at these boundaries and at the threshold
conditions are investigated.
