Manipulation of the granular fluid-structure interaction via sliding coating layers

Abstract

The use of sliding coating layers on structures is investigated as an approach to manipulate the transfer of momentum during the impact of granular matter with rigid and deformable structures. We first report an experimental investigation of the momentum transfer into rigid stationary targets with fixed and sliding coating layer impacted by high velocity granular slugs. Friction between the impacting granular particles and the target surface enhances the momentum transfer during the interaction with the target. By introducing a sliding coating layer with a lubricated target surface-coating interface, the momentum transfer is reduced: the coating slides on the target surface dragged along by friction between the coating and the particles but, the low friction between the coating and the target reduces the transfer of frictional forces into the target. Coupled discrete element and Lagrangian finite element simulations with rod-shaped granular particles are shown to capture the measurements with high fidelity. This numerical approach is then used to investigate the use of sliding coatings on deformable edge-clamped plates. Introduction of a coating layer while keeping the total mass of the plate constant, reduces the thickness of the plates and this in turn reduces their bending strength. The consequence is that momentum transfer reductions are lost as a result of the reduced bending strength and the minimum plate deflection is attained when no coating layer is present. We thus conclude that sliding coating layers can result in momentum transfer reductions when used on relatively rigid targets but result in a degradation of impact resistance performance when used on highly deformable structures.