Publications

2022

1. IEEE

   Efficient Simulation of Complex Capillary Effects in Advanced Manufacturing Processes using the Finite Volume Method

   Patrick Zimbrod, Magdalena Schreter, and Johannes Schilp

   2022

   Abs arXiv Bib PDF

   The accurate representation of surface tension driven flows in multi phase systems is considered a challenging problem to resolve numerically. Although there have been extensive works in the past that have presented approaches to resolve these so called Marangoni flows at the phase boundaries, the question of how to efficiently resolve the interface in a universal and conservative manner remains largely open in comparison. Such problems are of high practical relevance in many manufacturing processes, especially in the microfluidic regime where capillary effects dominate the local force equilibria. In this work, we present a freely available numerical solver based on the Finite Volume Method that is able to resolve arbitrarily complex, incompressible multi phase systems with the mentioned physics at phase boundaries. An efficient solution with respect to the number of degrees of freedom can be obtained by either using high order WENO stencils or by employing adaptive cell refinement. We demonstrate the capabilities of the solver by investigating a model benchmark case as well as a single track laser melting process that is highly relevant within laser additive manufacturing.

   @inproceedings{https://doi.org/10.1109/ICECCME55909.2022.9988504,
     doi = {10.1109/ICECCME55909.2022.9988504},
     author = {Zimbrod, Patrick and Schreter, Magdalena and Schilp, Johannes},
     keywords = {Numerical Analysis (math.NA), Materials Science (cond-mat.mtrl-sci), Fluid Dynamics (physics.flu-dyn), FOS: Mathematics, FOS: Mathematics, FOS: Physical sciences, FOS: Physical sciences},
     title = {Efficient Simulation of Complex Capillary Effects in Advanced Manufacturing Processes using the Finite Volume Method},
     publisher = {IEEE},
     isbn = {978-1-6654-7095-7},
     year = {2022},
     booktitle = {2021 International Conference on Electrical, Computer, Communications and Mechatronics Engineering (ICECCME)},
     copyright = {Creative Commons Attribution Non Commercial No Derivatives 4.0 International},
   }

2. Metals

   Frictionless motion of diffuse interfaces by sharp phase-field modeling

   Michael Fleck, Felix Schleifer, and Patrick Zimbrod

   2022

   Abs arXiv Bib PDF

   Diffuse interface descriptions offer many advantages for the modeling of microstructure evolution. However, the numerical representation of moving diffuse interfaces on discrete numerical grids involves spurious grid friction, which limits the overall performance of the model in many respects. Interestingly, this intricate and detrimental effect can be overcome in Finite Difference (FD) and Fast Fourier Transformation (FFT) based implementations by employing the so-called Sharp Phase-Field Method (SPFM). The key idea is to restore the discretization induced broken Translational Invariance (TI) in the discrete phase-field equation by using analytic properties of the equilibrium interface profile. We proof that this method can indeed eliminate spurious grid friction in the three dimensional space. Focussing on homogeneous driving forces, we quantitatively evaluate the impact of spurious grid friction on the overall operational performance of different phase-field models. We show that the SPFM provides superior degrees of interface isotropy with respect to energy and kinetics. The latter property enables the frictionless motion of arbitrarily oriented diffuse interfaces on a fixed 3D grid.

     doi = {10.48550/ARXIV.1910.05180},
     author = {Fleck, Michael and Schleifer, Felix and Zimbrod, Patrick},
     keywords = {Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, FOS: Physical sciences},
     title = {Frictionless motion of diffuse interfaces by sharp phase-field modeling},
     publisher = {MDPI},
     year = {2022},
     copyright = {Creative Commons Attribution 4.0 International},
   }

2021

1. ASIM

   Modelling of microstructures during in-situ alloying in additive manufacturing for efficient material qualification processes

   Patrick Zimbrod, and Johannes Schilp

   2021

   Abs arXiv Bib HTML PDF Slides

   In this work, a numerical simulation framework is presented based on the Phase Field Method that is able to capture the evolution of heterogeneous metallic microstructures during solidification. The involved physics can prove especially useful when studying not only systems undergoing thermal gradients, such as in homogeneous systems, but also in conditions that exhibit stark spatial gradients, i.e. when these inhomogeneities are present even on a mesoscopic scale. To illustrate the capabilities of the model, in-situ alloying of a High Entropy Alloy during Laser Powder Bed Fusion is investigated as an exemplary use case. The resulting digital twin is expected to shorten development times of new materials as well as cut down on experimental resource needs considerably, therefore contributing to efficient material qualification processes.

   @inproceedings{zimbrod_modelling_2021,
     title = {Modelling of microstructures during in-situ alloying in additive manufacturing for efficient material qualification processes},
     pages = {463--474},
     publisher = {Cuvillier Verlag},
     address = {Göttingen},
     isbn = {9783736974791},
     booktitle = {Simulation in Produktion und Logistik 2021},
     author = {Zimbrod, Patrick and Schilp, Johannes},
     editor = {Franke, Jörg and Schuderer, Peter},
     year = {2021},
   }