G100033 Numerical Analysis of Coupling Oscillation and Internal Resonance of Bifilar Suspension Pendulum

Abstract

A bifilar suspension pendulum, a uniform density bar suspended at its two points by two strings of same length, may swing in two vertical planes (Mode 1 and 2) or make torsional oscillation about a vertical axis (Mode 3). The period and pattern of the modes depend upon the ratios of the string length and of the distance of the supporting points to the distance between two end points of the strings attached to an upper wall. The three modes make linearly independent oscillation, but may give rise to nonlinear coupling. Typical couplings obtained so far in numerical computations are reported.