Presenter: Jinhui Yan, Department of Civil and Environmental Engineering, University of Illinois
November 1, 2022
8 AM Pacific / 9 AM Mountain / 10 AM Central / 11 AM Eastern
Abstract
Existing metal additive manufacturing (AM) models have difficulty handling the laser-metal inter-action and associated boundary conditions that significantly influence part quality metrics, such as defect and surface roughness. This talk presents a framework for simulating multiphysics processes in metal AM, focusing on better handling the 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 boundary conditions, 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 frameworkâs accuracy is assessed by thoroughly comparing the simulated results against experimental measurements from NIST and Argonne National Laboratory using in-situ high-speed, high-energy x-ray imaging. I will also report on other important quantities that experiments cannot measure to show the framework’s predictive capability.
Biography
Jinhui Yan is an assistant professor in the department of civil and environmental engineering at University of Illinois at Urbana-Champaign. He obtained his BS, MS, and Ph.D. from Wuhan University (2009), Peking University (2012), and University of California, San Diego (2016), re-spectively. After a two-year postdoc at Northwestern University, he joined the faculty of CEE@UIUC in 2018. He currently serves as the vice-chair of the CFD/FSI technical thrust of USACM and the Computational FSI committee of AMD/ASME. He is a committee member for both computational mechanics and fluid dynamics committees at EMI/ASCE. Two journal papers based on his Ph.D. work are among the most cited papers in Computer and Fluids in 2016 and 2017. He won the ASME Robert M. and Mary Haythornthwaite Young Investigator Award in 2018. He is a Levenick Teaching Fellow and often enters the list of excellent teachers ranked by the students at Illinois.