The objective of this paper is to unveil a novel damping mechanism exhibited by 3D woven lattice materials (3DW), with emphasis on response to high-frequency excitations. Conventional bulk damping materials, such as rubber, exhibit relatively low stiffness, while stiff metals and ceramics typically have negligible damping. Here we demonstrate that high damping and structural stiffness can be simultaneously achieved in 3D woven lattice materials by brazing only select lattice joints, resulting in a load-bearing lattice frame intertwined with free, ‘floating’ lattice members to generate damping.
The produced material samples are comparable to polymers in terms of damping coefficient, but are porous and have much higher maximum use temperature. We shed light on a novel damping mechanism enabled by an interplay between the forcing frequency imposed onto a load-bearing lattice frame and the motion of the embedded, free-moving lattice members. This novel class of damping metamaterials has potential use in a broad range of weight sensitive applications that require vibration attenuation at high frequencies.
Introduction
Phononic metamaterials prevent transmission of waves with certain frequency ranges via carefully engineered band gaps, stemming from Bragg scattering or local resonances. Bragg scattering results from destructive interference of waves moving through a periodic medium with periodicity comparable to the wavelength of incoming radiation1,2, while internal resonances arise from a frequency match between the incoming radiation and the resonance of internal masses, connected to the main structure by appropriately designed elastic springs3,4. Internal resonances are ultimately dissipated over time by intrinsic processes, resulting in energy damping. Such acoustic metamaterials have been heavily investigated over the past decade5,6,7, and find applications ranging from acoustic isolation8,9 to seismic meta-barriers4,10,11.
Here we explore an architected material consisting of a load-bearing lattice intertwined with a free-floating lattice. Akin to local resonance, the internal structure can vibrate, but momentum and energy transfer between the two sub-structures is provided by impact and friction, rather than elastic and visco-elastic interactions.
Read more: New Material – Bonded 3D woven lattice
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