Design analysis and experiment of double simply-supported cantilever beam-type anti-resonant vibration isolator

Objective To explore the implementation of a three-element-type anti-resonant vibration isolator, a mechanical device is proposed which is composed of a double simply-supported cantilever beam connecting to a mass block at the cantilever end and a double supported beam, i.e., beam-type anti-resonant vibration isolator (BAVI) .

Mehtods  First, the dynamic characteristics of the double simply-supported cantilever beam are analyzed and the impedance equation deduced. Based on the driving point impedance function, a low-order dynamic model of the double simply-supported cantilever beam is synthesized, which is a series model consisting of a single inertial volume and a single spring. The analytical solution of the equivalent parameters for the low-order dynamic model is also obtained. The isolator prototype is then made and the test is conducted. The experimental results validate the anti-resonant characteristics of the isolator device, and the effectiveness of the theoretical analysis is also verified. Furthermore, research on the stiffness characteristics and effects of different types of damping is carried out.

Results  The dynamic model of the isolator device accords with the three-element-type model when the span ratio is less than 1/6, and the isolator device has high static stiffness and low dynamic stiffness. By implementing one damping measure on the double simply-supported cantilever beam, the resonance can be absorbed while the transmissibility in the isolation frequency region attenuates at the maximum rate.

Conclusion The results of this study prove the realizability of the three-element-type anti-resonant vibration isolator, and the proposed mechanical device provides a simple and feasible implementation in engineering.