A consistent diffuse-interface finite element approach to rapid melt--vapor dynamics in metal additive manufacturing

2025-01-30

AI Summary

Modeling the strongly coupled melt pool–vapor dynamics in laser powder bed fusion (PBF-LB/M) remains challenging due to difficulties in capturing evaporation-induced pressure jumps and interfacial instabilities under highly non-equilibrium conditions. Method: We develop a physically consistent and numerically robust multiphysics diffuse-interface finite element model. For the first time within a diffuse-interface framework, we rigorously formulate triple discontinuities—pressure, volume fraction, and velocity—induced by evaporation. A projection-based method ensures consistent construction of interfacial source terms, extending the Anisimov evaporation model into a hybrid formulation valid under strong non-equilibrium. The model integrates an anisotropic, non-isothermal Navier–Stokes solver, a conservative level-set method, and a matrix-free adaptive finite element framework. Results: The model successfully reproduces the film-boiling benchmark and achieves, for the first time, high-fidelity bidirectional melt–vapor coupling simulations under steady-state laser irradiation in PBF-LB/M, unifying physical fidelity with computational robustness.

Technology Category

• Computer Vision: Low Level & Physics-based Vision
• Machine Learning: Large Multimodal Models (LMMs)
• Cognitive Modeling & Cognitive Systems: Simulating Human Behavior

Application Category

• User Modeling, Personalization and Recommendation: User modeling and simulation for interactive and conversational systems
• Systems and Infrastructure for Web, Mobile and WoT: Virtualization and resource management in Web systems and infrastructures
• Web Mining and Content Analysis: Models for Web evolution

Abstract

Metal additive manufacturing via laser-based powder bed fusion (PBF-LB/M) faces performance-critical challenges due to complex melt pool and vapor dynamics, often oversimplified by computational models that neglect crucial aspects, such as vapor jet formation. To address this limitation, we propose a consistent computational multi-physics mesoscale model to study melt pool dynamics, laser-induced evaporation, and vapor flow. In addition to the evaporation-induced pressure jump, we also resolve the evaporation-induced volume expansion and the resulting velocity jump at the liquid--vapor interface. We use an anisothermal incompressible Navier--Stokes solver extended by a conservative diffuse level-set framework and integrate it into a matrix-free adaptive finite element framework. To ensure accurate physical solutions despite extreme density, pressure and velocity gradients across the diffuse liquid--vapor interface, we employ consistent interface source term formulations developed in our previous work. These formulations consider projection operations to extend solution variables from the sharp liquid--vapor interface into the computational domain. Benchmark examples, including film boiling, confirm the accuracy and versatility of the model. As a key result, we demonstrate the model's ability to capture the strong coupling between melt and vapor flow dynamics in PBF-LB/M based on simulations of stationary laser illumination on a metal plate. Additionally, we show the derivation of the well-known Anisimov model and extend it to a new hybrid model. This hybrid model, together with consistent interface source term formulations, especially for the level-set transport velocity, enables PBF-LB/M simulations that combine accurate physical results with the robustness of an incompressible, diffuse-interface computational modeling framework.

Problem

• Metal 3D Printing
• Melt Pool Dynamics
• Vapor Ejection

Innovation

• Consistent Diffuse Interface Finite Element Method
• PBF-LB/M Technology
• Anisimov Model Integration