Broadband vibration attenuation characteristic of 2D phononic crystals with cross-like pores

The emergence and development of phononic crystals provide a feasible way to manipulate the propagation of elastic waves in structures. In this study, a class of single-phase 2D phononic crystals with tetragonal topology and cross-like pores is proposed. Both numerical simulation and theoretical analysis are performed to reveal the formation and regulation mechanism of bandgap and to obtain broadband vibration attenuation capability. The results show that the X-shaped pores can lead to the multiband and broadband characteristics of the structure, which are closely related to the coupling mechanisms of Bragg scattering and local resonance. In contrast, cross-shaped pores can open wide bandgaps at low frequencies. Notably, by means of identifying the bandgap edge modes to establish simplified vibrating systems, the analytical formulations derived from structural mechanics can accurately predict the bandgap edge frequencies, which provide effective guidance for bandgap tuning and structural design. Moreover, the vibration mitigation capability can be further enhanced by combining structures with different mass distributions. Compared with the multiphase structure, the structure proposed in this study is lighter and easier to fabricate, which provides significant guidance for the design of tunable phononic devices.