FEM: Mesh/Plasă de discretizare MEF
Creează o rețea MEF
Există modalități diferite de a crea o plasă de discretizare MEF în FreeCAD:
- Netgen FEM instrument Mesh FreeCAD MeshNetgenFromShape utilizând GUI sau Python
- FreeCAD FEM instrument de plasă GMSH MeshGmshFromShape utilizând GUI sau Python
- Python înseamnă a face direct FEM Mesh de mână
- Importați o plasă FEM
Obiectele create în PartDesign și Part sunt suportate, precum și copii simple ale acestor organisme. Două ochiuri sunt disponibile pentru utilizator: Netgen și GMSH. Netgen este inclus în FreeCAD. Pentru GMSH, trebuie instalat un binar extern. Consultați FEM Install
Elemente de plasă MEF în FreeCAD
FreeCAD acceptă diferite tipuri de elemente. Există o legătură externă de blog care explică diferențele și momentul de utilizare a tipului de element: https://www.comsol.com/blogs/meshing-your-geometry-various-element-types/
- "ni" înseamnă că tipul elementului nu este implementat în FreeCAD, dar formatul îl va suporta.
- "-" înseamnă că specificația formatului nu suportă acest tip de element, deci FreeCAD nu o poate suporta.
- "?" nu se știe dacă formatul acceptă acest tip de element.
Tipuri de Elemente MEF
General
Mai multe informații despre tipurile de elemente FEM și structura lor de date în cadrul FreeCAD pot fi găsite pe FEM Elements Types.
Segment element
Triangle element
Quadratic element
Tetrahedron element
Pyramid element
Hexahedron element
Pentahedron element
Scripting
Create a FEM Mesh totally py python
Creating a mesh with one Tet-10 Elements
import FreeCAD, Fem
# create a empty mesh
m = Fem.FemMesh()
#create the nodes
m.addNode(0,1,0)
m.addNode(0,0,1)
m.addNode(1,0,0)
m.addNode(0,0,0)
m.addNode(0,0.5,0.5)
m.addNode(0.5,0.03,.5)
m.addNode(0.5,0.5,0.03)
m.addNode(0,0.5,0)
m.addNode(0.03,0,0.5)
m.addNode(0.5,0,0)
# add the volume with the created nodes
m.addVolume([1,2,3,4,5,6,7,8,9,10])
Fem.show(m)
Dacă doriți să aveți o numerotare predefinită a elementelor și nodurilor:
m.addNode(0.0,1.0,0.0,1)
m.addVolume([1,2,3,4,5,6,7,8,9,10],1)
Manipulare vizuală
Evidențiați unele noduri din vizualizare:
import FreeCAD, Fem
m = Fem.FemMesh()
m.addNode(0,1,0)
m.addNode(0,0,1)
m.addNode(1,0,0)
m.addNode(0,0,0)
m.addNode(0,0.5,0.5)
m.addNode(0.5,0.03,.5)
m.addNode(0.5,0.5,0.03)
m.addNode(0,0.5,0)
m.addNode(0.03,0,0.5)
m.addNode(0.5,0,0)
m.addVolume([1,2,3,4,5,6,7,8,9,10])
Fem.show(m)
Gui.ActiveDocument.ActiveObject.HighlightedNodes = [1,2,3]
Culori și deplasări postprocesare: Evidențiați unele noduri din vizualizare:
# set the volume 1 to red
Gui.ActiveDocument.ActiveObject.ElementColor= {1:(1,0,0)}
# set the node 1 and 2 to a certain Color and interpolate the survace
Gui.ActiveDocument.ActiveObject.NodeColor= {1:(1,0,0),2:(1,0,0)}
# set the node 1 and 2 to a certain displacement
Gui.ActiveDocument.ActiveObject.NodeDisplacement= {1:FreeCAD.Vector(1,0,0),2:FreeCAD.Vector(1,0,0)}
# double the factor of the displacement shown
Gui.ActiveDocument.ActiveObject.animate(2.0)
Script un element al fiecărui tip de Element acceptat
import Fem
#################################################
# Beams
# 2 node line --> seg2 ##########################
seg2 = Fem.FemMesh()
seg2.addNode( 0, 0, 0, 1)
seg2.addNode(10, 0, 0, 2)
seg2.addEdge(1, 2)
seg2
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","seg2")
obj.FemMesh = seg2
obj.Placement.Base = (0,110,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
# 3 node line --> seg3 ##########################
seg3 = Fem.FemMesh()
seg3.addNode( 0, 0, 0, 1)
seg3.addNode(10, 0, 0, 2)
seg3.addNode( 5, 0, 0, 3)
seg3.addEdge([1, 2, 3])
seg3
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","seg3")
obj.FemMesh = seg3
obj.Placement.Base = (30,110,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
#################################################
# Shells
# 3 node triangle --> tria3 #####################
tria3 = Fem.FemMesh()
tria3.addNode( 0, 0, 0, 1)
tria3.addNode( 6, 12, 0, 2)
tria3.addNode(12, 0, 0, 3)
tria3.addFace([1, 2, 3])
tria3
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","tria3")
obj.FemMesh = tria3
obj.Placement.Base = (0,80,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
obj.ViewObject.BackfaceCulling = False
# add Face with element number
elemtria3 = Fem.FemMesh()
nds = tria3.Nodes
for n in nds:
elemtria3.addNode(nds[n].x, nds[n].y, nds[n].z, n)
elemtria3.addFace([1, 2, 3], 88)
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elemtria3")
obj.FemMesh = elemtria3
obj.Placement.Base = (200,80,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
obj.ViewObject.BackfaceCulling = False
elemtria3.Faces
# 6 node triangle --> tria 6 ####################
tria6 = Fem.FemMesh()
tria6.addNode( 0, 0, 0, 1)
tria6.addNode( 6, 12, 0, 2)
tria6.addNode(12, 0, 0, 3)
tria6.addNode( 3, 6, 0, 4)
tria6.addNode( 9, 6, 0, 5)
tria6.addNode( 6, 0, 0, 6)
tria6.addFace([1, 2, 3, 4, 5, 6])
tria6
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","tria6")
obj.FemMesh = tria6
obj.Placement.Base = (30,80,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
obj.ViewObject.BackfaceCulling = False
# add Face with element number
elemtria6 = Fem.FemMesh()
nds = tria6.Nodes
for n in nds:
elemtria6.addNode(nds[n].x, nds[n].y, nds[n].z, n)
elemtria6.addFace([1, 2, 3, 4, 5, 6], 88)
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elemtria6")
obj.FemMesh = elemtria6
obj.Placement.Base = (230,80,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
obj.ViewObject.BackfaceCulling = False
elemtria6.Faces
# 4 node quad --> quad4 #########################
quad4 = Fem.FemMesh()
quad4.addNode( 0, 10, 0, 1)
quad4.addNode(10, 10, 0, 2)
quad4.addNode(10, 0, 0, 3)
quad4.addNode( 0, 0, 0, 4)
quad4.addFace([1, 2, 3, 4])
quad4
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","quad4")
obj.FemMesh = quad4
obj.Placement.Base = (60,80,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
obj.ViewObject.BackfaceCulling = False
# add Face with element number
elemquad4 = Fem.FemMesh()
nds = quad4.Nodes
for n in nds:
elemquad4.addNode(nds[n].x, nds[n].y, nds[n].z, n)
elemquad4.addFace([1, 2, 3, 4], 88)
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elemquad4")
obj.FemMesh = elemquad4
obj.Placement.Base = (260,80,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
obj.ViewObject.BackfaceCulling = False
elemquad4.Faces
# 8 node quad --> quad8 #########################
quad8 = Fem.FemMesh()
quad8.addNode( 0, 10, 0, 1)
quad8.addNode(10, 10, 0, 2)
quad8.addNode(10, 0, 0, 3)
quad8.addNode( 0, 0, 0, 4)
quad8.addNode( 5, 10, 0, 5)
quad8.addNode(10, 5, 0, 6)
quad8.addNode( 5, 0, 0, 7)
quad8.addNode( 0, 5, 0, 8)
quad8.addFace([1, 2, 3, 4, 5, 6, 7, 8])
quad8
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","quad8")
obj.FemMesh = quad8
obj.ViewObject.BackfaceCulling = False
obj.Placement.Base = (90,80,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
# add Face with element number
elemquad8 = Fem.FemMesh()
nds = quad8.Nodes
for n in nds:
elemquad8.addNode(nds[n].x, nds[n].y, nds[n].z, n)
elemquad8.addFace([1, 2, 3, 4, 5, 6, 7, 8], 88)
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elemquad8")
obj.FemMesh = elemquad8
obj.Placement.Base = (290,80,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
obj.ViewObject.BackfaceCulling = False
elemquad8.Faces
#################################################
# Volumes
# 4 node tetrahedron --> tetra4 #################
tetra4 = Fem.FemMesh()
tetra4.addNode( 6, 12, 18, 1)
tetra4.addNode( 0, 0, 18, 2)
tetra4.addNode(12, 0, 18, 3)
tetra4.addNode( 6, 6, 0, 4)
tetra4.addVolume([1, 2, 3, 4])
tetra4
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","tetra4")
obj.FemMesh = tetra4
obj.Placement.Base = (0,50,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
# add Volume with element number
elemtetra4 = Fem.FemMesh()
nds = tetra4.Nodes
for n in nds:
elemtetra4.addNode(nds[n].x, nds[n].y, nds[n].z, n)
elemtetra4.addVolume([1, 2, 3, 4], 88)
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elemtetra4")
obj.FemMesh = elemtetra4
obj.Placement.Base = (200,50,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
elemtetra4.Volumes
# 10 node tetrahedron --> tetra10 ###############
tetra10 = Fem.FemMesh()
tetra10.addNode( 6, 12, 18, 1)
tetra10.addNode( 0, 0, 18, 2)
tetra10.addNode(12, 0, 18, 3)
tetra10.addNode( 6, 6, 0, 4)
tetra10.addNode( 3, 6, 18, 5)
tetra10.addNode( 6, 0, 18, 6)
tetra10.addNode( 9, 6, 18, 7)
tetra10.addNode( 6, 9, 9, 8)
tetra10.addNode( 3, 3, 9, 9)
tetra10.addNode( 9, 3, 9,10)
tetra10.addVolume([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])
tetra10
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","tetra10")
obj.FemMesh = tetra10
obj.Placement.Base = (30,50,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
# add Volume with element number
elemtetra10 = Fem.FemMesh()
nds = tetra10.Nodes
for n in nds:
elemtetra10.addNode(nds[n].x, nds[n].y, nds[n].z, n)
elemtetra10.addVolume([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 88)
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elemtetra10")
obj.FemMesh = elemtetra10
obj.Placement.Base = (230,50,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
elemtetra10.Volumes
# 8 node Hexahedron --> hexa8 ###################
hexa8 = Fem.FemMesh()
hexa8.addNode( 0, 10, 10, 1)
hexa8.addNode( 0, 0, 10, 2)
hexa8.addNode(10, 0, 10, 3)
hexa8.addNode(10, 10, 10, 4)
hexa8.addNode( 0, 10, 0, 5)
hexa8.addNode( 0, 0, 0, 6)
hexa8.addNode(10, 0, 0, 7)
hexa8.addNode(10, 10, 0, 8)
hexa8.addVolume([1, 2, 3, 4, 5, 6, 7, 8])
hexa8
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","hexa8")
obj.FemMesh = hexa8
obj.Placement.Base = (60,50,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
# add Volume with element number
elemhexa8 = Fem.FemMesh()
nds = hexa8.Nodes
for n in nds:
elemhexa8.addNode(nds[n].x, nds[n].y, nds[n].z, n)
elemhexa8.addVolume([1, 2, 3, 4, 5, 6, 7, 8], 88)
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elemhexa8")
obj.FemMesh = elemhexa8
obj.Placement.Base = (260,50,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
elemhexa8.Volumes
# 20 node Hexahedron --> hexa20 #################
hexa20 = Fem.FemMesh()
hexa20.addNode( 0, 10, 10, 1)
hexa20.addNode( 0, 0, 10, 2)
hexa20.addNode(10, 0, 10, 3)
hexa20.addNode(10, 10, 10, 4)
hexa20.addNode( 0, 10, 0, 5)
hexa20.addNode( 0, 0, 0, 6)
hexa20.addNode(10, 0, 0, 7)
hexa20.addNode(10, 10, 0, 8)
hexa20.addNode( 0, 5, 10, 9)
hexa20.addNode( 5, 0, 10, 10)
hexa20.addNode(10, 5, 10, 11)
hexa20.addNode( 5, 10, 10, 12)
hexa20.addNode( 0, 5, 0, 13)
hexa20.addNode( 5, 0, 0, 14)
hexa20.addNode(10, 5, 0, 15)
hexa20.addNode( 5, 10, 0, 16)
hexa20.addNode( 0, 10, 5, 17)
hexa20.addNode( 0, 0, 5, 18)
hexa20.addNode(10, 0, 5, 19)
hexa20.addNode(10, 10, 5, 20)
hexa20.addVolume([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20])
hexa20
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","hexa20")
obj.FemMesh = hexa20
obj.Placement.Base = (90,50,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
# add Volume with element number
elemhexa20 = Fem.FemMesh()
nds = hexa20.Nodes
for n in nds:
elemhexa20.addNode(nds[n].x, nds[n].y, nds[n].z, n)
elemhexa20.addVolume([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20], 88)
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elemhexa20")
obj.FemMesh = elemhexa20
obj.Placement.Base = (290,50,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
elemhexa20.Volumes
# 6 node pentahedron --> penta6 #################
penta6 = Fem.FemMesh()
penta6.addNode(10,10,10, 1)
penta6.addNode( 0, 0,10, 2)
penta6.addNode(20, 0,10, 3)
penta6.addNode(10,10, 0, 4)
penta6.addNode( 0, 0, 0, 5)
penta6.addNode(20, 0, 0, 6)
penta6.addVolume([1, 2, 3, 4, 5, 6])
penta6
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","penta6")
obj.FemMesh = penta6
obj.Placement.Base = (0,0,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
# add Volume with element number
elempenta6 = Fem.FemMesh()
nds = penta6.Nodes
for n in nds:
elempenta6.addNode(nds[n].x, nds[n].y, nds[n].z, n)
elempenta6.addVolume([ 1, 2, 3, 4, 5, 6], 88)
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elempenta6")
obj.FemMesh = elempenta6
obj.Placement.Base = (200,0,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
elempenta6.Volumes
# 15 node pentahedron --> penta15 ###############
penta15 = Fem.FemMesh()
penta15.addNode(10,10,10, 1)
penta15.addNode( 0, 0,10, 2)
penta15.addNode(20, 0,10, 3)
penta15.addNode(10,10, 0, 4)
penta15.addNode( 0, 0, 0, 5)
penta15.addNode(20, 0, 0, 6)
penta15.addNode( 5, 5,10, 7)
penta15.addNode(10, 0,10, 8)
penta15.addNode(15, 5,10, 9)
penta15.addNode( 5, 5, 0,10)
penta15.addNode(10, 0, 0,11)
penta15.addNode(15, 5, 0,12)
penta15.addNode(10,10, 5,13)
penta15.addNode( 0, 0, 5,14)
penta15.addNode(20, 0, 5,15)
penta15.addVolume([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15])
penta15
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","penta15")
obj.FemMesh = penta15
obj.Placement.Base = (40,0,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
# add Volume with element number
elempenta15 = Fem.FemMesh()
nds = penta15.Nodes
for n in nds:
elempenta15.addNode(nds[n].x, nds[n].y, nds[n].z, n)
elempenta15.addVolume([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15], 88)
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elempenta15")
obj.FemMesh = elempenta15
obj.Placement.Base = (240,0,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
elempenta15.Volumes
# 5 node pyramid --> pyra5 ######################
pyra5 = Fem.FemMesh()
pyra5.addNode( 0,20, 0, 1)
pyra5.addNode(20,20, 0, 2)
pyra5.addNode(20, 0, 0, 3)
pyra5.addNode( 0, 0, 0, 4)
pyra5.addNode(10,10,10, 5)
pyra5.addVolume([1, 2, 3, 4, 5])
pyra5
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","pyra5")
obj.FemMesh = pyra5
obj.Placement.Base = (80,0,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
# add Volume with element number
elempyra5 = Fem.FemMesh()
nds = pyra5.Nodes
for n in nds:
elempyra5.addNode(nds[n].x, nds[n].y, nds[n].z, n)
elempyra5.addVolume([1, 2, 3, 4, 5], 88)
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elempyra5")
obj.FemMesh = elempyra5
obj.Placement.Base = (280,0,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
elempyra5.Volumes
# 13 node pyramid --> pyra13 ####################
pyra13 = Fem.FemMesh()
pyra13.addNode( 0,20, 0, 1)
pyra13.addNode(20,20, 0, 2)
pyra13.addNode(20, 0, 0, 3)
pyra13.addNode( 0, 0, 0, 4)
pyra13.addNode(10,10,10, 5)
pyra13.addNode(10,20, 0, 6)
pyra13.addNode(20,10, 0, 7)
pyra13.addNode(10, 0, 0, 8)
pyra13.addNode( 0,10, 0, 9)
pyra13.addNode( 5,15, 5,10)
pyra13.addNode(15,15, 5,11)
pyra13.addNode(15, 5, 5,12)
pyra5 = Fem.FemMesh()
pyra13.addNode( 5, 5, 5,13)
pyra13.addVolume([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13])
pyra13
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","pyra13")
obj.FemMesh = pyra13
obj.Placement.Base = (120,0,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
# add Volume with element number
elempyra13 = Fem.FemMesh()
nds = pyra13.Nodes
for n in nds:
elempyra13.addNode(nds[n].x, nds[n].y, nds[n].z, n)
elempyra13.addVolume([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13], 88)
obj = App.ActiveDocument.addObject("Fem::FemMeshObject","elempyra13")
obj.FemMesh = elempyra13
obj.Placement.Base = (320,0,0)
obj.ViewObject.DisplayMode = "Faces, Wireframe & Nodes"
elempyra13.Volumes
- Materials: Solid, Fluid, Nonlinear mechanical, Reinforced (concrete); Material editor
- Element geometry: Beam (1D), Beam rotation (1D), Shell (2D), Fluid flow (1D)
Constraints
- Electromagnetic: Electrostatic potential, Current density, Magnetization
- Geometrical: Plane rotation, Section print, Transform
- Mechanical: Fixed, Displacement, Contact, Tie, Spring, Force, Pressure, Centrif, Self weight
- Thermal: Initial temperature, Heat flux, Temperature, Body heat source
- Overwrite Constants: Constant vacuum permittivity
- Solve: CalculiX Standard, Elmer, Mystran, Z88; Equations: Deformation, Elasticity, Electrostatic, Electricforce, Magnetodynamic, Magnetodynamic 2D, Flow, Flux, Heat; Solver: Solver control, Solver run
- Results: Purge, Show; Postprocessing: Apply changes, Pipeline from result, Warp filter, Scalar clip filter, Function cut filter, Region clip filter, Contours filter, Line clip filter, Stress linearization plot, Data at point clip filter, Filter function plane, Filter function sphere, Filter function cylinder, Filter function box
- Additional: Preferences; FEM Install, FEM Mesh, FEM Solver, FEM CalculiX, FEM Concrete; FEM Element Types
- Getting started
- Installation: Download, Windows, Linux, Mac, Additional components, Docker, AppImage, Ubuntu Snap
- Basics: About FreeCAD, Interface, Mouse navigation, Selection methods, Object name, Preferences, Workbenches, Document structure, Properties, Help FreeCAD, Donate
- Help: Tutorials, Video tutorials
- Workbenches: Std Base, Arch, Assembly, CAM, Draft, FEM, Inspection, Mesh, OpenSCAD, Part, PartDesign, Points, Reverse Engineering, Robot, Sketcher, Spreadsheet, Start, Surface, TechDraw, Test Framework, Web
- Hubs: User hub, Power users hub, Developer hub