Performance of pendulum absorber for a nonlinear system of varying orientation

Pendulum-type vibration absorbers are used extensively in engineering. These devices are particularly useful in practical applications where oscillations of a structure are to be constrained within a prescribed envelope. In this study, the primary structure under investigation consists of a flexible beam with a tip mass. The primary structure has a single degree of freedom and is subjected to vertical sinusoidal excitation at its base. Non-linearity in the primary structure is due to large deflections. The rotation point of the pendulum-type absorber is connected to the primary structure's tip mass. Together, the primary structure and absorber constitute a coupled system with two degrees of freedom. The motivation for study was the need to understand the effectiveness of passive vibration absorbers on structures that change their orientation, e.g., satellites. The primary objective is to assess the effectiveness of pendulum-type passive vibration absorber attached to a primary structure whose orientation varies. The orientations are at five degree increments about a vertical plane. In this study the orientation at which the absorber is effective is established and the factors that affect performance of the absorber are highlighted.