Dynamic characteristic analysis of the inerter-based piecewise vibration isolator under base excitation

An inerter-based piecewise (IPW) vibration isolator is proposed in this paper to further improve the isolation performance of the piecewise vibration isolator without using an inerter. The IPW vibration isolator integrates the bilinear property of the piecewise vibration isolator and the mass magnification property of the inerter. Based on the arrangement of the inerter and damper, the IPW vibration isolator would have different forms. Herein, the parallel-connected (PC) and series-connected (SC) forms in the secondary structure of the IPW vibration isolator are designed, where the inerter and damper are in PC and SC forms, respectively. The two forms are defined as PC-IPW and SC-IPW vibration isolators. The dynamic response of the IPW vibration isolator under base excitation is acquired using the averaging method. The isolation performance of the IPW vibration isolator is evaluated by using three performance criteria: displacement amplitude peak, absolute displacement transmissibility peak, and isolation frequency band. The results demonstrate that the PC-IPW vibration isolator has a smaller displacement amplitude peak, smaller absolute displacement transmissibility peak and wider isolation frequency band than the piecewise and linear vibration isolators. The three performance criteria of the SC-IPW vibration isolator fall between the values of the piecewise and linear vibration isolators. In addition, the PC-IPW vibration isolator obtains the best isolation performance among the four vibration isolators. Therefore, the design of the IPW vibration isolator shows the benefits of introducing an inerter and offers an effective option for designing a piecewise vibration isolator with excellent isolation performance in practical engineering.