Dynamic Vibration Absorber

About: Dynamic Vibration Absorber is a research topic. Over the lifetime, 4764 publications have been published within this topic receiving 49429 citations.

Vibration absorber for a racket

Abstract: In construction of a vibration absorber for a racket, a mass is indirectly supported by a visco-elastic member arranged within the grip or the yoke of the racket via an elongated interface so that resonant swing of the interface on receipt of vibration from the head of the racket should cause deformation of the visco-elastic member for thermal diffusion of vibration energy. The visco-elastic member is sandwiched between two elongated leaf springs. One end of the leaf spring is mounted to the wall of the racket handle and the other end of the leaf spring supports the mass. By proper choice of the component, vibration in a specified frequency range can be selectively damped so as to match vibration characteristics of rackets of various types.

Evaluation of the Autoparametric Pendulum Vibration Absorber for a Duffing System

Abstract: In this work we study the frequency and dynamic response of a damped Duffing system attached to a parametrically excited pendulum vibration absorber. The multiple scales method is applied to get the autoparametric resonance conditions and the results are compared with a similar application of a pendulum absorber for a linear primary system. The approximate frequency analysis reveals that the nonlinear dynamics of the externally excited system are suppressed by the pendulum absorber and, under this condition, the primary Duffing system yields a time response almost equivalent to that obtained for a linear primary system, although the absorber frequency response is drastically modified and affected by the cubic stiffness, thus modifying the jumps defined by the fixed points. In the absorber frequency response can be appreciated a good absorption capability for certain ranges of nonlinear stiffness and the internal coupling is maintained by the existing damping between the pendulum and the primary system. Moreover, the stability of the coupled system is also affected by some extra fixed points introduced by the cubic stiffness, which is illustrated with several amplitude-force responses. Some numerical simulations of the approximate frequency responses and dynamic behavior are performed to show the steady-state and transient responses.

Vibration absorber for vehicle wiper devices

Abstract: A vibration absorber is provided between a wiper frame and a vehicle body frame The vibration absorber includes a cylinder and a pair of flanges arranged near opposite axial ends of the cylinder The cylinder is fitted in an opening formed in the wiper frame The cylinder has a through hole through which a bolt is inserted One flange is located between the wiper frame and a washer secured to the bolt The other flange is located between the wiper frame and the body frame Each flange has an arched axial cross-sectional shape The flanges reliably absorb axial vibration of the wiper frame

MR Damper Controlled Vibration Absorber for Enhanced Mitigation of Harmonic Vibrations

Abstract: This paper describes a semi-active vibration absorber (SVA) concept based on a real-time controlled magnetorheological damper (MR-SVA) for the enhanced mitigation of structural vibrations due to harmonic disturbing forces. The force of the MR damper is controlled in real-time to generate the frequency and damping controls according to the behaviour of the undamped vibration absorber for the actual frequency of vibration. As stiffness and damping emulations in semi-active actuators are coupled quantities the control is formulated to prioritize the frequency control by the controlled stiffness. The control algorithm is augmented by a stiffness correction method ensuring precise frequency control when the desired control force is constrained by the semi-active restriction and residual force of the MR damper. The force tracking task is solved by a model-based feed forward with feedback correction. The MR-SVA is numerically and experimentally validated for the primary structure with nominal eigenfrequency and when de-tuning of −10%, −5%, +5% and +10% is present. Both validations demonstrate that the MR-SVA improves the vibration reduction in the primary structure by up to 55% compared to the passive tuned mass damper (TMD). Furthermore, it is shown that the MR-SVA with only 80% of tuned mass leads to approximately the same enhanced performance while the associated increased relative motion amplitude of the tuned mass is more than compensated be the reduced dimensions of the mass. Therefore, the MR-SVA is an appropriate solution for the mitigation of tall buildings where the pendulum mass can be up to several thousands of metric tonnes and space for the pendulum damper is limited.