Underexcitation prevents crystallization of granular assemblies subjected to high-frequency vibration
Abstract
Crystallization of dry particle assemblies via imposed vibrations is a scalable route to assemble micro/macro crystals. It is well understood that there exists an optimal frequency to maximize crystallization with broad acceptance that this optimal frequency emerges because high-frequency vibration results in overexcitation of the assembly. Using measurements that include interrupted X-ray computed tomography and high-speed photography combined with discrete-element simulations we show that, rather counterintuitively, high-frequency vibration underexcites the assembly. The large accelerations imposed by high-frequency vibrations create a fluidized boundary layer that prevents momentum transfer into the bulk of the granular assembly. This results in particle underexcitation which inhibits the rearrangements required for crystallization. This clear understanding of the mechanisms has allowed the development of a simple concept to inhibit fluidization which thereby allows crystallization under high-frequency vibrations.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 10, 2023
- Source ID
- 10.1073/pnas.2306209120
Entities
People
- Angkur Jyoti Dipanka Shaikeea
- H.N.G. Wadley
- Ivan Grega
- Sara AlMahri
- Vikram S Deshpande
Organizations
- Army Research Office
- Technology Innovation Institute
- University of Cambridge
- University of Virginia