A CutFEM method for Stefan-Signorini problems with application in pulsed laser ablation

TL;DR

This paper introduces a novel CutFEM approach for solving Stefan problems in laser manufacturing, effectively handling complex moving interfaces without re-meshing, and demonstrating optimal convergence and robustness in 2D and 3D applications.

Contribution

The paper presents a new CutFEM method for Stefan problems that remains stable regardless of interface position and avoids re-meshing, with proven optimal convergence.

Findings

Method remains stable independent of cut location

Achieves optimal convergence in space and time

Demonstrated robustness in 2D and 3D examples

Abstract

In this article, we develop a cut finite element method for one-phase Stefan problems, with applications in laser manufacturing. The geometry of the workpiece is represented implicitly via a level set function. Material above the melting/vaporisation temperature is represented by a fictitious gas phase. The moving interface between the workpiece and the fictitious gas phase may cut arbitrarily through the elements of the finite element mesh, which remains fixed throughout the simulation, thereby circumventing the need for cumbersome re-meshing operations. The primal/dual formulation of the linear one-phase Stefan problem is recast into a primal non-linear formulation using a Nitsche-type approach, which avoids the difficulty of constructing inf-sup stable primal/dual pairs. Through the careful derivation of stabilisation terms, we show that the proposed Stefan-Signorini-Nitsche CutFEM method remains stable independently of the cut location. In addition, we obtain optimal convergence with respect to space and time refinement. Several 2D and 3D examples are proposed, highlighting the robustness and flexibility of the algorithm, together with its relevance to the field of micro-manufacturing.