The coupled band gap of the double beam with attached periodic spring-mass structure

This study presents a novel investigation into the phenomenon of coupled band gaps within double beam structures and achieves the construction of beam configurations featuring inherent coupled band gaps. Initially, the identification of coupled band gaps in double beam structures is discussed, and it is engineered within the low-frequency range by adjusting the thickness ratio of the two beams. Subsequently, double beam models are constructed using various methods. A comparative analysis between the Spectral Element Method and the Plane Wave Expand method validates the existence of coupled band gaps. Furthermore, through systematic exploration using the Plane Wave Expand method, we investigate the effect of different parameters on coupled band gaps. The attenuation properties within the identified coupled band gap are experimentally validated using double beam Finite Element models and a dedicated experiment for forced vibration testing. Consequently, controlled variations in thickness ratio confirm well-defined coupled band gaps exist in conventionally thick beam structures. Within this specific frequency range (254-279 Hz) for the double beam with thicknesses 0.01 m and 0.002 m, respectively, average attenuation rates of -3.79 dB and -11.16 dB are recorded correspondingly. It significantly contributes to applying theories on coupled band gaps to large-scale architectural frameworks.