COMPLAS 2023

Towards a sharp phase-field method: a hybrid diffuse-semisharp approach for microstructure evolution problems

  • Dobrzanski, Jędrzej (IPPT PAN)
  • Stupkiewicz, Stanisław (IPPT PAN)

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The phase-field method is a numerical technique used to simulate microstructure evolution in materials. It is based on the notion of diffuse interfaces, in which the interfaces have a finite thickness that defines a region in which material parameters transition from one phase to another. The conventional phase-field approach requires a fine mesh resolution to represent diffuse interfaces accurately. However, this can result in high computational costs because the fine-mesh requirement limits the size of the problem that can be simulated. There is thus a need to develop improved approaches that would overcome this notable limitation of the phase-field method. For instance, in the context of the finite-difference method, a sharp phase-field approach has been developed in [1] that eliminates the grid pinning effect and thus enables the use of arbitrary interface thicknesses. In line with this concept, we present a new technique that combines the phase-field method with the laminated element technique (LET) [2] to model interfaces in a semi-sharp manner. LET is a finite-element-based method used to model weak discontinuities using a non-conforming mesh. Its primary characteristic is the use of laminated microstructures to approximate the interface within only those finite elements that are cut by the interface. As a result, in the mechanical subproblem, the transition from one phase to another is performed only within the finite elements cut by the interface, allowing for a coarser mesh resolution. The proposed approach is demonstrated through various computational examples that are pertinent to the micromechanics of heterogeneous materials. The examples specifically focus on elastic materials under small-strain framework. The implementation and computations were performed using the AceGen-AceFEM environment. Our results demonstrate that, in some cases, our method outperforms the classical phase-field method. [1] Finel A., Bouar Y. L., Dabas B., Appolaire B., Yamada Y., Mohri T. Sharp phase field method. Physical Review Letters, 121(2), 2018. [2] Dobrzański J., Wojtacki K., Stupkiewicz S. Lamination-based efficient treatment of weak discontinuities for non-conforming finite element meshes, 2023 (submitted).