Multi-physics Modeling of 3D Printing of Metallic Materials

A Mixed Diffusive-Sharp Interface Approach for Multi-physics Modeling of 3D Printing of Metallic Materials

A Warren Distinguished Lecture with Jinhui Yan, Civil and Environmental Engineering, University of Illinois Urbana-Champaign

Abstract
Existing metal additive manufacturing (AM) models have difficulty handling the laser-metal interaction and associated boundary conditions (BCs) that significantly influence part quality, such as defect and surface roughness. In this talk, Jinhui Yan 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 multi-physics model 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. 

Yan demonstrates 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 in-situ high-speed, high-energy x-ray imaging. Yan also reports other important quantities that experiments cannot measure to show the framework's predictive capability.

Speaker
Jinhui Yan is an assistant professor in the Department of Civil and Environmental Engineering (CEE) at University of Illinois at Urbana-Champaign (UIUC). He obtained his BS from Wuhan University (2009), MS from Peking University (2012), and Ph.D. University of California, San Diego (2016). After a two-year postdoc at Northwestern University, he joined the faculty of CEE at UIUC. His research group broadly works on computational mechanics and their applications. He won the ASME Robert M. and Mary Haythornthwaite Young Investigator Award in 2018 and Gallagher Young Investigator Medal from U.S. Association for Computational Mechanics in 2023. The AM model developed by his research group won second place in the 2022 NIST AM benchmark modeling contests. He is a Levenick Teaching Fellow and often enters the list of excellent teachers ranked by the students at UIUC. He currently serves as the vice-chair of the computational fluid dynamics (CFD) and fluid-structure interaction (FSI) technical thrust of USACM and the Computational FSI committee of AMD/ASME.