Vibration control of a pendulum structure by a dynamic vibration absorber moving in both normal and tangential directions

Abstract

There are two types of dynamic vibration absorbers (DVAs) for vibration reduction of a pendulum structure. The first one moving in the tangential direction of the pendulum's orbit can reduce all kinds of vibrations but the effectiveness is quite poor when the DVA locates near the centre of oscillation. Conversely, the second one moving in the normal direction of the pendulum's orbit can only reduce large vibration but has a good effect when the DVA's location is near the centre of oscillation. In this article, the authors propose the DVA, which can move in the normal and tangential directions at the same time. The proposed DVA can overcome the shortcoming of two DVAs moving in only one direction. Because the system's non-linearity is quite complex, a numerical method is used for obtaining the optimal parameters. Then, the authors introduce the convenient empirical formulas of optimal parameters based on the numerical results. The effect of the proposed DVA is demonstrated by the numerical calculations of free vibration of a ropeway gondola.

Sequential design of two orthogonal dynamic vibration absorbers in a pendulum based on stability maximization

“…The full non-linear equations (8) are used in the numerical calculations in 'Numerical verifications' section. Before moving further, some characteristics of each type of DVA are briefly summarized 8 1.…”

“…The full non-linear equations (8) are used in the numerical calculations in 'Numerical verifications' section. Before moving further, some characteristics of each type of DVA are briefly summarized 8 1. The DVA moving in the tangential direction (with mass m v ) is mainly driven by the first-order terms, while the DVA moving in the tangential direction (with mass m u ) is mainly driven by the second-order terms.…”

“…However, each type of DVA has advantages and disadvantages. 8 The idea of combination of two types of DVA has recently studied. 8 Two possible combinations are shown in Figure 1.…”

“…This combination can have better performance in comparison with that of single DVA moving in only one direction. 8 It is well-known that the DVA effectiveness depends on the DVA mass ratio and the DVA location. Because of using only one DVA, the scheme in Figure 1(a) has the advantage of the DVA mass ratio but the disadvantage of the DVA position.…”

Combination of Partial Stochastic Linearization and Karhunen-Loeve Expansion to Design Coriolis Dynamic Vibration Absorber

“…The theory of linear DVA is well developed in literature [1] for a variety of excitations of interest, including the random excitation. In pendulum structures such as ropeway gondola or floating structures (e.g., ships or tension leg platforms), using DVA reveals several surprising and interesting facts not met in normal systems, including location problem, Coriolis force, and gyroscopic moment [2][3][4][5][6][7][8]. The Coriolis DVA has been studied in the cases of harmonic and free vibrations [5,6] but not the case of random vibration.…”