  Cellular materials not only show interesting static properties but can also
be used to manipulate dynamic mechanical waves. In this contribution, the
existence of phononic band gaps in periodic cellular structures is
experimentally shown via sonic transmission experiment. Cellular structures
with varying numbers of cells are excited by piezoceramic actuators and the
transmitted waves are measured by piezoceramic sensors. The minimum number of
cells necessary to form a clear band gap is determined. A rotation of the cells
does not have an influence on the formation of the gap, indicating a complete
phononic band gap. The experimental results are in good agreement with the
numerically obtained dispersion relation.
