Optimization of the Vibration Isolation Performance of an Impact-testing Machine Using Multi-walled Carbon Nanotubes Reinforced Elastomeric Machine Mounts

The objective of this paper is to investigate the vibration isolation performance of an impact testing machine mounted on elastomeric nanocomposite mounts. An effective analytical-experimental test method was implemented in this paper to characterize the vibration isolation performance of acrylonitrile-butadiene rubber (NBR) mounts reinforced with multi-walled carbon nanotubes (MWCNTs). This method utilizes modal tests in order to measure experimental transfer functions (TFs) of a impact testing machine as a correlation parameter to analytical-experimental determined TFs. The optimization procedure is carried out using a genetic algorithm (GA) by minimizing the difference between the experimental data from modal tests and the calculated response. A series of NBR mounts were manufactured with different concentrations of MWCNTs. The vibration isolation capacity of the machine mounts was determined through the transmissibility of a suitably designed test system. Elastomers' vibration isolation performance was ameliorated with the inclusion of MWCNTs, signifying that the enhancement of the elastomers with MWCNTs was rather effective. It is also shown that the stiffness of an elastomer and its damping capacity can be tuned by adjusting the proportion of MWCNTs. The vibration level of the impact-testing machine was decreased to 91% by incorporating the optimal concentration of MWCNTs in NBR mounts.