Frequency Separation in Architected Structures using Inverse Methods

A major goal in the design of architected structures for low frequency vibration applications (also called mechanical metamaterials, metastructures, elastic metamaterials, auxetic structures) is the creation of regions in the frequency domain where vibration amplitudes are minimal, regardless of the source of excitation. The idea is to provide vibration suppression in manmade structures. The proposed effort is to examine approaches to produce straightforward methods of designing a given mechanical metamaterial to have a specified gap in the frequency spectrum by adjusting its local mass and stiffness values of the individual cells. Previous work in mechanical metamaterial design has focused on using optimization procedures concerned with global vibration suppression. Here our efforts are focused on frequency separation using two direct approaches by interpreting techniques from the areas of model updating and inverse eigenvalue solutions. Rather than examining the overall suppression of vibration, creating specific bandgaps eliminates the possibility of resonance occurring in a given range of excitation frequencies.