Design And Analysis Of A Disc Rubber Vibration Isolator With Quasi-zero-stiffness Characteristic

Vibration and noise reduction is one of the most important research areas nowadays in which linear vibration isolation theory is hull-fledged and has wide applications in engineering. According to classical theory of vibration isolation, we know that linear vibration isolator can perform its function only when excitation frequency is larger 2 times than isolator's natural frequency. If we broad frequency region, especially for low frequency region, of vibration isolation via decreasing the nature frequency, the system ma y meet stability problem. Thus the nonlinear vibration isolation theory need s further exploration.A new type design of disc rubber vibration isolator with quasi-zero-stiffness(QZS) characteristic is proposed based on the theory and design principle of the QZS. The QZS isolator was devised by assembling a reinforced disc rubber with negative stiffness property with a vertical rubber cylinder with positive stiffness characteristic in parallel which has characteristic of low frequency vibration isolation.The key design procedure is choosing perfect matching of positive and negative stiffness which achieves zero stiffness property at balance position. A qualified model of reinforced disc rubber with negative stiffness property is designed b y means of Abaqus simulation. The micro-convex reinforcement form is proposed and the feasibility of this design is analsized. Next, the rubber model with positive stiffness is also analsized and the whole model of disc rubber with quasi-zero-stiffness characteristic is built with revising model parameters repeatedly. The stiffness characteristic of the QZS system was analyzed by means of Abaqus simulation and zero stiffness property is observed. Next, two methods is adopted to get the force transmissibility of QZS vibration isolation system. One is numerical simulation in which the force-displacement relationship of QZS system was replaced by a approximate nonlinear model by fitting the FEA simulations data. Then governing equation of the vibration isolation system is formulated and the force transmission curve of the system is obtained by Matlab simulation. We analysize the effect of damping ? stiffness and excitation amplitude on QZS characteristic of vibration isolation system. The other method is dynamic simulation by Abaqus. The force transmission curve of the system is obtained by the response under different excitation frequency. The two methods have demonstrated that the QZS isolator has the superior characteristic of low-dynamic-high-static stiffness and may realize low-frequency vibration isolation. Compared with the corresponding linear vibration isolation with the same system parameters, the QZS isolator not only broadens the isolation frequency band, but also reduces the resonance peak.Finally, an experimental bench of diaphragm spring vibration isolator with QZS characteristic is set up. The static experiment of diaphragm spring vibration isolator was carried out, and a force-displacement curve is obtained and demonstrated the QZS characteristic of the vibration isolator. The results of dynamic experiment revealed that the QZS isolator has better isolation performance compared with the corresponding linear one.