Large band gaps in phononic crystal slabs with rectangular cylinder inclusions parallel to the slab surfaces

•We model a novel phononic crystal slab with rectangular cylinder inclusions.•A large band gap is observed in the band structure of the phononic crystal slab.•The band gap is significantly dependent on the geometries of the inclusions.•The geometries work on the gap by modulating the neck stiffness and plate shapes.

The propagation of Lamb waves in a new phononic crystal slab composed of rectangular cylinder inclusions embedded periodically in a host material is investigated. The band structure of the phononic crystal is calculated and the influences of the geometry parameters of inclusions on the band structure are discussed. Results show that large band gap occurs in the phononic crystal slab and the band gap is significantly dependent on the width, height and rotation of the inclusions. Moreover, the eigenmodes of the Lamb waves are given to explain the relationship between the band gap and the geometry parameters of the inclusions.