Abstract

Improving product quality of machining components has always met with problems due to the vibration of the milling machine’s spindle, which can be reduced by adding a vibration absorber. The tuned vibration absorber (TVA) has been studied extensively and found to have a narrow bandwidth, but the cutting force possesses wide bandwidth in the process of machining parts. Introducing nonlinearity into the dynamic vibration absorber can effectively increase the bandwidth of vibration suppression and can significantly improve the robustness of the vibration absorber. In addition, a semiactive TVA has proved to be more effective than a passive TVA for many applications, so the main purpose of this study is to find some appropriate semiactive control methods for a nonlinear energy sink (NES), a nonlinear vibration absorber, in structural vibration applications. Two semiactive control methods are considered in this study: continuous groundhook damping control based on velocity and on-off groundhook damping control based on velocity. To fairly compare these vibration absorbers, the optimal parameters of a passive TVA, a passive NES, and two semiactive NESs are designed using numerical optimization techniques to minimize the root-mean-square acceleration. Two cutting forces are introduced in this study, a periodic force and an aperiodic force, and the four vibration absorbers are compared. When the primary structure is excited with aperiodic cutting force, the amplitude of the primary structure decreased by 17.73% with the passive TVA, by 72.29% with the passive NES, by 73.54% with the on-off NES, and by 87.54% with the continuous NES. When the primary structure is excited with periodic cutting force, the amplitude of the primary structure decreased by 49.01% with a passive TVA, by 86.93% with a passive NES, by 96.38% with an on-off NES, and by 99.23% with a continuous NES. The results show that the passive NES is better than the passive TVA; the semiactive NES provides more effective vibration attenuation than the passive NES, and the continuous control is more effective than the on-off control.

Highlights

  • A tuned vibration absorber (TVA) is a vibration absorbing device that is attached to a primary system to control vibration

  • Optimal Results with the Aperiodic Cutting Force. e displacement of the primary structure of every optimal system is shown in Figure 7, from which we can see the amplitude of displacement with a semiactive nonlinear energy sink (NES) attenuates faster than that with a passive NES, and the amplitude of displacement with a passive NES attenuates faster than that with a passive TVA during the steady cutting stage

  • Optimal Results with the Periodic Cutting Force. e displacement of the primary structure of every optimal system is shown in Figure 10, from which we can see the displacements of main structures with semiactive NESs kTVA−opt 8.41 × 106 Ns/m ccontrol (N/m) cTVA−opt 171.05 Ns/m N/A

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Summary

Introduction

A tuned vibration absorber (TVA) is a vibration absorbing device that is attached to a primary system to control vibration. It is usually composed of a mass, a linear stiffness, and a viscous damper. E passive TVA described above has simple structure but poor control effect, so the active TVA and semiactive TVA were successively studied by scholars. An active system can provide good performance, but it becomes more complex at the same time. Many problems arise such as the selection of sensors, power supply, weight constraints, stability, and robustness [3]. A number of studies have introduced the advantages of semiactive control over passive control [6,7,8,9,10,11,12,13,14]

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