Vibration isolation concept by switchable stiffness on a semi-active pneumatic actuator

Abstract In this paper a novel technique of switchable stiffness dedicated to vibration isolation is presented. The approach utilises a semi-active pneumatic device in which the stiffness switching is obtained via controlled thermodynamic processes. The concept for the dissipation technique is introduced and a mathematical model is proposed. The system is analysed under passive and semi-active modes of operation by means of numerical simulation and in an experimental survey. The analysis consists of the model validation, an energy dissipation process study and a verification of effectiveness of the concept under varying operational conditions. As a result, it is demonstrated that the proposed technique allows for combining advantages of controllable pneumatic springs and pneumatic dampers, which constitutes an added value. It is revealed in the conducted tests that the system allows for 147% increase in energy dissipation per vibration cycle and reduce the resonant amplitude peak by 8%, both in comparison to a passive gas damper. The presented concept introduces an innovative approach to the switching stiffness techniques dedicated to vibration mitigation. The findings may significantly expand the number of their implementation possibilities.