  We study the Bloch oscillation of elastic waves in a chain composed of hollow
elliptical cylinders (HECs). These HECs are 3D-printed in different wall
thicknesses and are arranged to form a graded chain. We find that the frequency
band structure of this lattice can be manipulated in a way to create a narrow
strip of transmission range sandwiched between slanted stop bands. This enables
the trapping of elastic waves at a specific location of the chain, which
depends on the input frequency of the propagating elastic waves. This elastic
Bloch oscillation in a tailorable 3D-printed system enables the control of
energy localization in solids, potentially leading to engineering applications
for vibration filtering, energy harvesting, and structural health monitoring.
