On the linear elastic, isotropic modeling of poroelastic distributed vibration absorbers at low frequencies

Abstract

Several past works have considered a passive vibration absorber device utilizing distributed mass and spring layers. The thickness of the poroelastic foam spring and the area density of the mass layer are modified to achieve a target natural frequency of the device while the foam itself provides adequate dissipation of energy as the mass dynamically compresses it at resonance. A model of the device earlier developed is briefly reviewed and validated by new experiments. The dependence of the absorber natural frequency and damping on the poroelastic spring thickness is observed in detail and is found to be consistent with past work on poroelastic material elastic characteristics outside of the linear dynamic regime. The results set a practical limit on the applicability of linearity assumptions in the present modeling of the distributed poroelastic vibration absorbers and thus determine a design parameter range for which the computationally efficient model is accurate.