Colloquia

Summary

Vibration isolation is necessary to mitigate disturbances in machinery with high accuracy requirements. This can be done using passive mechanical elements. This study reveals a novel leaf spring-based negative stiffness mechanism that is designed for high vibration isolation bandwidth purposes along a single axis. The design is based on specific requirements, primarily achieving a target negative stiffness while ensuring minimum variation in the stiffness for a given operation range. Additionally, it must maintain low dynamic stiffness from the saturation point, across all operating range for the mechanism up to required isolation range. The geometrical properties of leaf springs with relevant boundary conditions are achieved by means of solving an optimization problem. The mechanism is designed, manufactured and tested to investigate its performance to satisfy these requirements.

In order to assess the static performance of the mechanism, static stiffness test is carried for total operation range of the mechanism. The test reveals required nominal stiffness and the variation in the static stiffness for operation range. For the dynamic performance, dynamic stiffness test is carried out up to a certain frequency. Dynamic stiffness test reveals the internal dynamic performance of the mechanism and their effect on isolation performance for different operating positions. The proposed negative stiffness mechanism proves the feasibility of passive isolation devices that require high internal modes with low static stiffness.