COMSOL Exchange - by COMSOL

Micromagnetics Module for COMSOL Multiphysics

Mon, 29 Sep 2025 00:48:15 +0000

Micromagnetics Module has been updated to V2.13. Please note that the new module is not compatible with the mph files created by versions before V2.0.

The dynamics of magnetization in magnets are described by micromagnetic theory, governed by the Landu–Lifshitz–Gilbert equations. We built a customized "Micromagnetics Module" using the Physics Builder, which can be used to perform micromagnetic simulations within the framework of the COMSOL. This Micromagnetics Module can be coupled straightforwardly to other add-on modules to perform multiphysics micromagnetic simulations, such as magneto-dipolar coupling, magnetoelastic coupling, magnet-thermal coupling, and more. The module package, along with a user’s guide, is available for download.

The tutorial examples can accessed through the following Application Exchange page:
//m.COMSOL.com/community/exchange/1033/

For more information about the module, please read the COMSOL Blog: https://www.comsol.com/blogs/micromagnetic-simulation-with-comsol-multiphysics

Questions and comments are encouraged to be left here.

Phonon hydrodynamics module for COMSOL Multiphysics

Tue, 16 Sep 2025 08:46:43 +0000

This user guide presents the Phonon hydrodynamics module (V1.0) for COMSOL Multiphysics, enabling simulation of viscous heat transport in high-conductivity materials. The module implements the viscous heat equations (VHE), a mesoscopic framework that extends Fourier’s law by coupling temperature evolution with phonon drift velocity dynamics, capturing hydrodynamic phenomena such as Poiseuille flow, second sound, heat backflow, and thermal vortices. The guide provides detailed instructions for module installation via the COMSOL Physics Builder, including importing the builder file and adding the viscous heat equations interface to user models. Users are guided on applying temperature, heat flux, drift velocity, slip, and no-slip boundary conditions, supporting both steady-state and time-dependent simulations. Example cases illustrate classical versus hydrodynamic heat transport, incompressible-flow limits, vortex formation, and oscillatory boundary-driven dynamics. Default parameters are provided for materials with first-principles transport coefficients, such as diamond, silicon, graphite, and hexagonal boron nitride. By bridging full Boltzmann transport calculations and continuum diffusion theory, the module offers a practical, efficient approach for exploring non-diffusive, hydrodynamic heat transport in complex geometries. Complementary COMSOL files accompany the guide, allowing users to replicate and extend the examples.

Figure source: E. Di Lucente, F. Libbi, and N. Marzari, "Vortices and backflow in hydrodynamic heat transport", arXiv preprint arXiv:2501.16580 (2025).

Photonic Crystal Cavity Design Project

Tue, 22 Jul 2025 22:08:42 +0000

This application consists of a multi-step simulation to analyze and design a 1-dimensional photonic crystal cavity. It contains two eigen mode solvers, one for the driving waveguide and one for the photonic crystal, to identify the dispersion of the waveguide and the pass/stop bands. It also contains an optimization routine which seeks identifies the best defect size to maximize the electric field in the cavity. Finally, a frequency domain solver is included to determine the transmission of the structure throughout the visible spectrum. The app is intended to be used as a teaching tool in courses related to integrated photonics and nanophotonics.

Comparative Analysis via CFD Simulation on the Impact of Graphite Anode Morphologies on the Discharge of a Lithium-Ion Battery

Fri, 18 Jul 2025 06:08:47 +0000

The morphology of electrode materials plays a crucial role in determining the performance of lithium-ion batteries. Traditional computational models often simplify graphite flakes as uniformly sized spheres, which limits their predictive accuracy. In this study, we present a computational workflow that overcomes these limitations by incorporating a more realistic representation of graphite morphologies. This workflow is designed to be flexible and reproducible, enabling efficient evaluation of electrochemical performance across diverse material structures. By exploring different graphite morphologies, our approach accelerates the optimization of material preparation techniques and processing conditions. Our findings reveal that incorporating greater morphological complexity leads to significant deviations from classical model predictions. Instead, our refined model offers a more accurate representation of battery discharge behavior, closely aligning with experimental data. This improvement underscores the importance of detailed morphological descriptions in advancing battery design and performance assessments. To promote accessibility and reproducibility, we provide the developed code for seamless integration with the COMSOL API, allowing researchers to implement and adapt it easily. This computational framework serves as a valuable tool for investigating the impact of graphite morphology on battery performance, bridging the gap between theoretical modeling and experimental validation to enhance lithium-ion battery technology.

EMF1 - Designing Capacitors Lab

Wed, 16 Jul 2025 22:40:18 +0000

Lab Application for Undergraduate Electromagnetics:
Students will explore a real design scenario for a capacitor structure to meet designated performance metrics using properties of real dielectric materials. Students will utilize and compare both analytical and numerical techniques, and explore non-idealities in capacitor designs and how to incorporate them into the design. Students will gain intuition into how geometry and materials affects capacitance as well as the potential and fields produced by a parallel plate capacitor.

Mathematical modeling of surface deformation during vitrification

Sat, 07 Dec 2024 23:54:34 +0000

The behavior of the cryoprotective agents changes from liquid to solid during vitrification. In this model, I solved the coupled problem of heat transfer and fluid flow problem during cryopreservation, while considering surface tension. The results are in good agreement with the cryomacroscopy experiments.

This is a multi-physics model I developed in a small project in October 2019 to model large surface deformation and residual stresses during cryopreservation by vitrification.
To learn about cryopreservation: Bojic et al. Winter is coming: the future of cryopreservation. BMC Biol 19, 56 (2021).
To cite my model:
Guirguis, Rabin, "Modeling surface deformation in large-scale cryopreservation by vitrification," Cryobiology, 97 (264), December 2020. DOI: 10.1016/j.cryobiol.2020.10.064
Link: https://doi.org/10.1016/j.cryobiol.2020.10.064

Emergent chiral spin textures in centrosymmetric iron garnet with spin alignment constraints

Fri, 06 Dec 2024 05:37:30 +0000

Chiral spin textures have emerged as a captivating class of topological matter. These intriguing structures harbor
localized and topologically protected magnetic textures, rendering them promising candidates for novel spin-
tronic applications. Here, the emergent chiral spin textures in an iron garnet with nanodisk configuration have
been micromagnatically simulated based on the Landau-Lifshitz-Gilbert equation (LLG) of COMSOL Multi-
physics. The modification of magnetic spin texture in the considered iron garnet has been controlled by intro-
ducing the interfacial Dzyaloshinskii-Moriya interaction (I-DMI) and spin alignment constraints as locally pinned
spins and curvilinear defects at edges. These boundary conditions induced interesting chiral textures not
commonly observed in such iron garnet due to its centrosymmetric crystal structure. The simulation results
showed the presence of two distinct regions of spin texture: inside and outside the pinning boundary. By sys-
tematically varying the DMI strength (D) with the size of the pinning boundary (Rpin) and the number of defects
(Ndef), the emerging chiral spin textures have been explored and reported, including the existence of ramified
helical stripes, skyrmions, and skyrmions-like textures such as elongated skyrmions, chiral horseshoe domains,
biskyrmions and target skyrmions (TSk) (2π-TSk and 3π-TSk). Also, it has been reported that various collapses
occur in the final spin texture states, leading to the transition from one state to another when varying the values
of Rpin and Ndef with D.

Tutorial Examples for Micromagnetic Module

Mon, 11 Nov 2024 09:22:06 +0000

With the help and guidance of my mentor Weichao Yu, I have completed the following ten micro-magnetism simulation cases in the video https://www.bilibili.com/video/BV1EL4y1p7bN/?spm_id_from=333.999.0.0&vd_source=d864e544d9d218aeece5a6b335cf07cf .Solutions were stripped so you will have to run the simulation to see the results, and hope that it can help others who want to use the micromagnetics module.

These models were done mainly using the Micromagnetics module with Comsol 5.6. You can click here to download //m.COMSOL.com/community/exchange/883/

Model for Transient Absorption and Raman Scattering of Vibrating Noble Metal Nanoparticles

Mon, 28 Oct 2024 20:06:22 +0000

Transient absorption and Raman scattering measurements on noble metal nanoparticles offer complimentary information on their vibrational modes and mechanical interactions with their surroundings. We have built a COMSOL application for simulating both of these spectra for arbitrary nanoparticle geometry and different metal compositions. This multiphysics application uses the Solid Mechanics and Electromagnetic Wave modules, takes into account local changes in dielectric function for the metals, and can model the small vibrational amplitudes of real transient absorption measurements.

For more information on the method and to cite my model, consult:
Gelfand, Rachel, “Unified Finite-element Model for Transient Absorption and Raman Scattering of Vibrating Noble Metal Nanoparticles,” J. Phys. Chem. C 2024, 128, 41, 17526–17535

https://doi.org/10.1021/acs.jpcc.4c04071

Grating diffraction model

Wed, 13 Mar 2024 08:10:31 +0000

The result of the time domain pulse signal passing through the narrow grating opening of the metal substrate.

Mobius Waveguide

Tue, 19 Sep 2023 00:59:06 +0000

We present a simple model of a Mobius loop waveguide, carrying RF in fundamental mode (TE10, rectangular) circulating endlessly around the loop. An animation is included. Enjoy.

COMSOL model file cleanup script

Sat, 02 Sep 2023 01:59:09 +0000

First a definition of cleanup: remove the mesh builds, solutions, and compact the history of a COMSOL model file.

I have found that getting in the COMSOL GUI each time I need to clean up the mph model files is sometimes inconvenient. Therefore, I wrote a little bash script to do this from the command line using the COMSOL batch option. I have attached the script for general use by the COMSOL user community.

Happy cleaning !

Paper Mechanics and the Benefits of Modeling Paperboard Formation

Tue, 21 Mar 2023 08:41:40 +0000

Formation is a fundamental physical characteristic of paper that can have profound effects on the production and performance of that paper. The finite element method can be utilized to better understand how formation affects mechanical quality control tests and their results. Using the Lorentzen & Wettre (L&W) bending resistance (15°) test, we investigate how paperboard formation affects bending resistance.

This model is used in the blog post "Paper Mechanics and the Benefits of Modeling Paperboard Formation" by Dr. Eric Linvill:

https://www.comsol.com/blogs/paper-mechanics-and-the-benefits-of-modeling-paperboard-formation/

Modeling Multi-Ply Materials with Composite Materials Technology

Tue, 21 Mar 2023 08:39:30 +0000

There are several ways to model multi-ply materials such as paperboard. Using a solid model with a thin domain for each layer is an obvious solution, but COMSOL also provides specific tools for modeling composite materials: the equivalent single layer (ESL) and layerwise theory (LWT) methods.

This model is used in the blog post "Modeling Multi-Ply Materials with Composite Materials Technology" by Dr. Eric Linvill:

https://www.comsol.com/blogs/modeling-multi-ply-materials-with-composite-materials-technology/

In silico assessment of electrophysiological neuronal recordings mediated by magnetoelectric nanoparticles

Tue, 27 Sep 2022 15:20:16 +0000

Magnetoelectric materials hold untapped potential to revolutionize biomedical technologies. Sensing of biophysical processes in the brain is a particularly attractive application, with the prospect of using magnetoelectric nanoparticles (MENPs) as injectable agents for rapid brain-wide modulation and recording. Recent studies have demonstrated wireless brain stimulation in vivo using MENPs synthesized from cobalt ferrite (CFO) cores coated with piezoelectric barium titanate (BTO) shells. CFO–BTO core-shell MENPs have a relatively high magnetoelectric coefficient and have been proposed for direct magnetic particle imaging (MPI) of brain electrophysiology. However, the feasibility of acquiring such readouts has not been demonstrated or methodically quantified.

In order to evaluate the feasibility of using MENPs for recording neural activity, we created a custom COMSOL model for MENP response quantification. Our strain-based model is versatile and adaptable to different materials and geometries if material parameters are known. Our study, its results, and source files are open source and source files can be found here: https://github.com/ilhanbok/InSilicoNeuronalMENPs

Citation:

Bok I, Haber I, Qu X, Hai A. In silico assessment of electrophysiological neuronal recordings mediated by magnetoelectric nanoparticles. Sci Rep. 2022 May 19;12(1):8386. doi: 10.1038/s41598-022-12303-4. PMID: 35589877; PMCID: PMC9120189.

Enlarged GSTCs simulations in the frequency domain

Mon, 19 Sep 2022 06:36:05 +0000

This archive provide the 2D and 3D models used in our paper

Nicolas Lebbe, Kim Pham and Agnès Maurel, "Stable GSTC formulation for Maxwell’s equations", IEEE Transactions on Antennas and Propagation ( Volume: 70, Issue: 8 )
DOI: https://doi.org/10.1109/TAP.2022.3161436
Preprint: https://hal.inria.fr/hal-03203013/document

These models implements in the frequency domain the enlarged version of the Generalized Sheet Transition Conditions (GSTC) used in electromagnetism to simulate the behaviour of thin periodic microstructures.

Investigation of 1D Compressible Navier Stokes Using Equation-Based Modeling

Sat, 21 May 2022 19:04:53 +0000

The subject paper was presented at the 2020 COMSOL Virtual Boston Conference and received the best paper award. At that time, the author committed to releasing an application to reproduce the results shown in the paper and allow the users to experiment with the new stabilization method described. The author has also received many requests for this application. This exchange contribution provides the full model file (as opposed to an application), whereas, the reader/user will have full access to all the details described by the paper. Two model files are uploaded: (1) Burger's equation solver, and (2) shock tube solver. Of course, the user may change anything, but it is recommended to start with simple changes such as the number of elements, the element order (linear, quadratic, etc.), Reynolds number, or the selection of ideal/real gas in the shock tube model. The author and co-author have continued their collaboration, and are nearing publication of results for the 2D compressible flow extension to this new stabilization method. We look forward to sharing this new information with the COMSOL user and development community.

Chirality of plasmonic structure

Sun, 16 Jan 2022 13:17:50 +0000

Circular dichroism is useful in chirality sensing. This archive provide the 3D models for calculating circular dichroism of plasmonic chiral structure.

Elastic Relaxation of Pre-stressed Bilayer Clamped Only At One Edge

Fri, 04 Dec 2020 13:26:02 +0000

In recent decade, the principle of bimetal bending was exploited in the field of thin films. Rolled-up micro- to nanotubes with multiple windings were obtained with this technology as well as wrinkled nanostructures. The competition of these two morphologies is studied by simulation of elastic relaxation with the help of Structural Mechanics Module. The structure consists of first layer compressed initially and second layer without initial strain. If the difference of the initial strains of the layers is sufficiently large, bending into the tube is preferred, otherwise wrinkling is observed. For medium strain gradient, intermixing shape of tube with wrinkles is the result of elastic relaxation. Additional information and qualitative experimental comparison can be found in article P. Cendula et al, Experimental realization of coexisting states of rolled-up and wrinkled nanomembranes by strain and etching control, Nanoscale 2014, 14326 - 14335, http://pubs.rsc.org/en/content/articlelanding/2014/nr/c4nr03986f

Classic DLVO Equivalent Sphere in COMSOL: Derjaguin Approximation

Tue, 01 Dec 2020 05:33:56 +0000

The interaction energies of colloids according to Classic DLVO based on the Derjaguin Approximation. The Classic DLVO consists of the non-retarded Attractive van der Waals interaction and the Repulsive electrostatic interaction energies. The equations are for a Sphere-Plate configuration and constant surface potential. The constant surface potential includes to models: one based on Hogg et al and other based on the Linear Superposition Approximation (LSA). It assumes an equivalent sphere for simplicity. The equations are broadly used in colloid science. Made in COMSOL 5.5.
REFS:
*Elimelech, Menachem, John Gregory, and Xiadong Jia. Particle deposition and aggregation: measurement, modelling and simulation. Butterworth-Heinemann, 2013.
*Hogg, R. T. W. D. W., To Wo Healy, and D. W. Fuerstenau. "Mutual coagulation of colloidal dispersions." Transactions of the Faraday Society 62 (1966): 1638-1651.
*Bhattacharjee, Subir, and Menachem Elimelech. "Surface element integration: a novel technique for evaluation of DLVO interaction between a particle and a flat plate." Journal of colloid and interface science 193, no. 2 (1997): 273-285.
*Gomez-Flores, Allan, Scott A. Bradford, Lei Wu, and Hyunjung Kim. "Interaction energies for hollow and solid cylinders: Role of aspect ratio and particle orientation." Colloids and Surfaces A: Physicochemical and Engineering Aspects 580 (2019): 123781.