Band Gaps of structures based on concrete-steel and concrete-molybdenum. Comparison between structures with square and hexagonal periodicities

Abstract

In this article, a study of the frequency dispersion curves of a periodic structure was made. The cell units of the base model are made of steel cylinders coated with a rubber layer embedded in a concrete thin mat. The results show the existence of three band gaps which means that we have no propagation waves. In second step, the steel core has been substituted with molybdenum. A noticeable shift towards the low frequencies has been achieved together with an improvement in the relative widths of the band gaps. In addition, a comparison of band gaps was made between a finites two-dimensional structure with square periodicity and hexagonal periodicity. The results showed that a square periodicity of a two-dimensional structure is more favourable for the field of civil engineering wich is necessary to be in a low frequencies.

Keywords

• seismic isolation
• bands gap: phononic cristals
• transmission