3D printing

Our 3DP effort is directed toward the understanding of fibre-filled systems, particularly large-aspect ratio fibres in a plastic matrix. The plastic itself is a viscoelastic material, and with the addition of fibres, one has a viscoelastic suspension. In a flow process, such as the fused deposition method (FDM) often employed in 3DP, the fibres’ concentration and orientation change with the flow; both affect the stresses contributed and therefore modelling the orientation and concentration in a fibre-filled system is important  in understanding the FDM.  Click below for a pdf version of a presentation to the NUMIFORM 2016.

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Smoothed particle hydrodynamics (SPH) modeling of fiber orientation in a 3D printing process, E Bertevas, J Férec, BC Khoo, G Ausias, N Phan-Thien, Physics of Fluids 30 (10), 103103

The simulation is done for a polylactic acid (PLA) as a solvent, with fibres of aspect ratio 30, volume fraction 0.03. The injection velocity ration Up/Us plays a major role in fibre orientation here.

Contours of Axx showing developing fibres orientation aligned with the flow at the skin (at the free surface and at solid boundary), while oriented more randomly at the core region.