3D rainbow phononic crystals for extended vibration attenuation bands

Area of Science:

• Materials Science
• Acoustics
• Mechanical Engineering

Background:

• Traditional phononic crystals (PnCs) and metamaterials leverage periodic designs for enhanced dynamic properties.
• Additive manufacturing enables the production of complex geometries, leading to innovative broadband vibration attenuation solutions.
• Rainbow metamaterials and PnCs, utilizing gradient profiles, show potential for expanding vibration attenuation spectra.

Purpose of the Study:

• To report the design, manufacturing, and testing of a novel three-dimensional (3D) nearly-periodic, locally resonant phononic crystal (PnC).
• To investigate the potential of non-periodic PnC designs for advanced vibration attenuation.
• To develop a lightweight and manufacturable PnC with significantly improved attenuation bandwidths.

Main Methods:

• Design of a nearly-periodic PnC based on cuboid blocks connected by curved beams.
• Implementation of internal voids within blocks to adjust local masses and create a 3D rainbow PnC.
• Testing and comparison of the proposed PnC's performance against equivalent periodic designs.

Main Results:

• The proposed nearly-periodic PnC exhibits a manufacturable design with internal voids for mass adjustment.
• The 3D rainbow PnC demonstrates vibration attenuation bandwidths more than two times larger than equivalent periodic designs.
• The approach results in lightweight phononic crystal structures.

Conclusions:

• Nearly-periodic PnC designs, particularly those incorporating rainbow effects, represent a promising direction for future research and engineering applications.
• The developed PnC offers a significant advancement in broadband vibration attenuation capabilities.
• The study validates the effectiveness of nearly-periodic, locally resonant designs for superior vibration control.