Prototype design and experimental verification of an electromagnetic actuator for parametric stiffness excitation

Initial design, realization and application of a novel electromagnetic actuator to create a time-harmonic variation of a mechanical stiffness will be discussed. It is known from theoretical studies, that such a time-periodic parameter variation at a non-resonant parametric resonance frequency can improve the damping behaviour of a mechanical system. Thus, a device consisting of a current driven coil positioned between two permanent magnets has been designed and tested. Finite element analyses have been carried out to obtain the mechanical stiffness provided as a function of the coil current excitation. With this novel electromagnetic actuator it is possible to demonstrate the improved damping behaviour of a mechanical two-mass system, when the actuator is operating at or near a certain parametric combination resonance frequency.