Pendulum-type elastic metamaterial for reducing the vibration of a space tether

In this paper, we present a pendulum-type elastic metamaterial that can be used to absorb the shock of a tether system. A tether system comprises a long and thin cable, so the resonant part of the elastic metamaterial should be attached to outside the cable. The unit cell of the elastic metamaterial consists of three strings and one ring, and strings are attached to the tether cable and reduces the shock transmitted to the satellite. We used modal analysis to find mode shapes of the unit cell of the elastic metamaterial that do not deform when in contact with the tether cable. A harmonic analysis on the properties of the strings confirmed the presence of bandgaps for the pendulum-type metamaterial because of the lateral resonance of the strings. The effect of the unit cell design parameters on the bandgaps were also investigated.