CEE Seminar - Computational multi-physics for metal additive manufacturing: methods and applications

Existing metal additive manufacturing (AM) models
have difficulty handling the laser-metal interaction
and associated boundary conditions (BCs) that
significantly influence part quality metrics, such as
defect and surface roughness. This talk presents a
sharp-diffusive interface computational method
for simulating multiphysics processes in metal AM,
focusing on better handling gas-metal interface,
where metal AM physics mainly takes place. The
framework consists of two components. The first is
a mixed interface-capturing/interface tracking
method to explicitly track the gas-metal interface
topological changes without mesh motion or
remeshing. The second is an enriched immersed
boundary method (EIBM) to impose the critical
flow, heat, and phase transition Neumann BCs,
which are enforced in a smeared manner in current
AM models, on the gas-metal interface with strong
property discontinuity.
I will demonstrate how the developed model
elucidates the fundamental metal AM physics (e.g.,
melt pool dynamics, keyhole instability, and
powder spattering) and predicts critical part
quality-related quantities (e.g., defect and surface
roughness). The proposed framework's accuracy is
assessed by thoroughly comparing the simulated
results against experimental measurements from
NIST and Argonne National Laboratory using insitu
high-speed, high-energy x-ray imaging. I will
also report other important quantities that
experiments cannot measure to show the
framework's predictive capability.