I'm still having trouble importing the geometry for this simple model. New_Toy_Coil.step New_Toy_Coil.msh2 Beyond this, I also wondered whether this toolbox can consider the anisotropic form of the vector magnetostatics equation - i.e the del x (1/mu(r)) curl x A = J which would be significantly more interesting to study. msh2 file in case recreating this is required to find a solution: This is key because the internal subdomain contains all source points and I'm mostly interested in the magnetic fields in the space around the 3D coil.Įdit: I have attached an example. I saw in the documentation that multiple sub-domains are supported in 3D, I'm just unclear on the process to properly import such a geometry. STEP gives two sub-domains but I cannot progress to gridding without somehow merging the geometries: msh2 file if you prefer) works, but the internal subdomain is lost - i.e I get an empty box which prevents me from making progress:Īlternatively, importing the. The geometry of the entire system can be seen in the figure below, where the internal structure is a current carrying coil with rectangular cross section which is wholly enclosed by a box to form a black-box simulation.Ĭurrently importing grid via a. The coherence command, plus physical groups for each subdomain are used to produce a coherent mesh with a list of domain IDs to identify which elements belong to which subdomain. ![]() Specifically I'm looking at (initially) solving the vector Poisson equation for the 3D magnetic vector potential across a domain, in the presence of a 3D current source.Ĭurrently from older work I have produced a non-coherent. So I hope you get an idea how to use Meshx, If you are working with FEniCS.I'm interested in making use of the FEA Toolbox. MeshFunctionSizet( mesh, mvc_2) # creating mesh function for surface #- # Define Dirichlet boundary conditions at top and bottom boundaries bcs = ), DirichletBC( V, 0.0, boundaries, tags)] #- # Define new measures associated with the interior domains and # exterior boundaries dx = Measure( "dx")( subdomain_data= domains) ds = Measure( "ds")( subdomain_data= boundaries) #- # Define variational form F = ( inner( a0 * grad( u), grad( v)) * dx( tags) + inner( a1 * grad( u), grad( v)) * dx( tags) - g_L * v * ds( tags) - g_R * v * ds( tags) - f * v * dx( tags) - f * v * dx( tags)) read( mvc_2, "tag") print( "Constructing MeshFunction from MeshValueCollection") domains = cpp. MeshFunctionSizet( mesh, mvc_1) # creating mesh function for curve with XDMFFile( "mesh/triangle.xdmf") as infile: print( "Reading 2d surface data into dolfin mvc") infile. read( mvc_1, "tag") print( "Constructing MeshFunction from MeshValueCollection") boundaries = cpp. load( f) with XDMFFile( "mesh/line.xdmf") as infile: print( "Reading 1d line data into dolfin mvc") infile. mvc_1 = MeshValueCollection( "size_t", mesh, 1) #for curve with dim 1 mvc_2 = MeshValueCollection( "size_t", mesh, 2) #for surface with dim 2 #import the json file so that tag names can be used f = open( 'mesh/tags.json') tags = json. # Define mesh mesh = Mesh() with XDMFFile( "mesh/triangle.xdmf") as infile: infile. So you have to create two mesh function corresponding to curve and surface mesh entity. In this case we are marking the boundary condition in curve mesh entity and the material subdomain is marked in the surface mesh entity. In FEniCS, we can make use of this by creating the mesh function corresponding to the mesh entities. All the files in mesh folder is used in the main script and the files in the sub_domains folder can be used to ensure if all the different sub domains are marked properly by visualizing the. meshx plate.mshĪs a output you will be getting two folders namely – “mesh and sub_domains”. msh file and use the following command to convert. Open the terminal and go to the folder containing the. Script for this is : Point( 1) = Īfter creating the. Įxample : Consider a rectangle section with four boundary condition, and two materials. This tool Meshx will only work if the Physical groups are marked properly. Mark all the different boundary and loading condition using the different Physical groups in Gmsh. Step by step procedure :Ĭreate the mesh file in Gmsh. You can get the complete installation instruction here. MeshxĪ simple tool to convert mesh created from Gmsh to XDMF for use in FEniCS. In this post I will mainly focus on Gmsh because thats what I mostly prefer to use as it is an open-source GUI-based package. Check this post to know how to use Nastran file (.bdf) from Ansys to FEniCS. ![]() As it allows us to use different packages (Gmsh, Ansys, Abaqus etc) for complex geometry modeling and meshing. This makes our job much more easier and simpler. In FEniCS we have an option of importing the mesh geometry in. How to use MeshX to convert the mesh file from Gmsh to XDMF file in FEniCS
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