Optimal Parameters and Characteristics of a Three Degree of Freedom Dynamic Vibration Absorber

The present study is devoted to the determination of the optimal parameters and characteristics of a three degree of freedom dynamic vibration absorber (3 DOF DVA) for the vibration reduction of a plate at a given point. The optimization scheme uses simulated annealing and constrained simulated annealing, which is capable of optimizing systems with a set of constraints. Comparisons between a 3 DOF DVA and multiple (5) 1 DOF DVAs show a better performance of the former for vibration reduction. Regarding the characteristics of the optimal 3 DOF DVA, numerical tests reveal that the absorber is robust under variations of the observation point and for 10% variations of its mass, stiffness and damping. From the analysis of parameter changes of the plate, it is found that the optimal 3 DOF DVA is almost insensitive to a mass change, and sensitive to a change of Young’s modulus for low frequencies. In this case, a decrease in Young’s modulus causes a decrease in its effectiveness, and an increase improves it. The study of the effect of the 3 DOF DVA location on its effectiveness reveals that the requirements of closeness of the absorber to an antinode of the bare primary structure and to the observation point improve its performance. Additionally, for a rotational mode of the 3-DOF DVA about some axis, the effectiveness of the absorber at a given frequency can be notably increased if it is located at a position of the primary system with an in-phase or out-of- phase motion of the attachment points according to the rotational-mode characteristics of the 3-DOF DVA at this frequency.