The development of additive manufacturing (AM) methods in metallurgy has provided new opportunities to accurately design engineering parts with complex topologies. With the benefits of reducing production costs and design time, AM has increasingly been implemented for full scale commercial use as a reliable method to manufacture metallic parts. This is of particular importance to industries involved with aeronautic, medical, and automotive research, where there is little room for production errors. However, much of the underlying multiphysics involved with AM remain elusive and are critical to understand to ensure the quality of manufactured parts. Methods of metal printing, such as directed energy deposition (DED), typically involve processes where powder-based filament is melted and fed through a nozzle to be deposited onto a substrate, layer by layer. The deposited metal material then rapidly cools down and solidifies to the desired geometry. In general, these lead to fully coupled thermomechanical processes that give rise to a so-called Stefan problem, where solid-liquid phase transitions occur along a moving boundary.
Continuum-mechanical formulations of these phase transitions have long required attention since the conception of additive manufacturing and necessitates careful treatment to model such processes. In this talk we will discuss previous approaches that have been taken to model the additive manufacturing process in the context of solving a transient heat transfer problem, followed by a solid mechanics problem. Then we will discuss what an updated model might look like in the context of solving the Stefan problem. An overview of the mechanics involved with solidification processes will be provided, along with their relevant constitutive laws and governing equations.
About Me: I completed my undergraduate bachelor's degree at Berkeley in civil engineering, initially intending to study Structural Mechanics, but pivoted to solid mechanics within the Computational Solid Mechanics lab at Berkeley. Since then I have taken an interest in material modeling under the framework of continuum thermomechanics and continuum plasticity, along with their numerical implementation to validate such models. I work under the supervision of Professor Papadopoulos and currently center my research around the Stefan problem to understand material behavior as it undergoes phase transformations along a moving boundary. My Own Personal Website: aaronmachuca.com