Band gap tuning and wave separator design in 3 d composite slab structures based on periodic thermal fields

In the thesis, we investigate a two-dimensional period slab composite structure composed of steel/epoxy and adhered with a series of heat films. Various types of periodic thermal fields are introduced into the structure by loading diverse powers of heat on the heat films. Leveraging the thermal sensitivity of epoxy, these introduced thermal fields facilitate changes and tuning in the band structures of the composite slab. Therefore, a thermal–mechanical coupling model based on finite element method via commercial software is established to obtain the dispersion curves and transmission spectrums of the period structure. The numerical prediction of band gaps indicates that band structures of composite slabs can be effectively tuned by thermal fields. Furthermore, intelligent waveguides and wave separators are designed by thermal fields with line-type or L-type of thermal defects. The results also exhibit an interesting phenomenon that in-plane wave and out-of-plane wave can be decoupled when T-type of thermal defects with proper heat flux are employed. The results of this research may lay theoretical foundation and provide a novel routine for the designing of intelligent acoustic devices such as waveguides and wave separators.