Passive vibration control by isolation uncouples a source from a receiving structure. The effect is dependent on the frequency of the source excitation, whether it is a transient input such as a shock, the dynamic characteristics of the source and receiver and also whether there is any damping in the isolation.
Shock isolation using switchable stiffness
The shock response can be reduced if the isolation produces a low natural frequency of the equipment moving on the isolation, but this is unacceptable for supporting the static load of the equipment. So this project switches the stiffness by electromagnets during the input time.
Shock isolation using friction
Friction is introduced onto the isolated mass, or an attached mass-spring system, to reduce the response during the shock input and the residual vibration after the shock. Control strategies for when to apply the friction to get the maximum benefit are established.
Isolation systems with nonlinear (cubic) damping
A detrimental effect of linear viscous damping is the isolation response at frequencies above the isolation frequency. This project has considered the potential of nonlinear damping (i.e. proportional to velocity cubed), as measured in automotive shock absorbers, for the case of base and force excitation.
