FEM Element Types

    From FreeCAD Documentation

    Introduction

    This description is based on the MED format as described in modele de donnes.

    Segment element

    FEM mesh elements 1 segment.svg

    Edges of Seg2 and Seg3
    Edge Node 1 Node 2 Middle node
    E1 N1 N2 N3

    Triangle element

    FEM mesh elements 2 triangle.svg

    Edges of Tria3 and Tria6
    Edge Node 1 Node 2 Middle node
    E1 N1 N2 N4
    E2 N2 N3 N5
    E3 N3 N1 N6
    Face by Edges of Tria3 and Tria6
    Face Edge 1 Edge 2 Edge 3
    F1 E1 E2 E3
    Face by Nodes of Tria3
    Face Node 1 Node 2 Node 3 Node 1
    F1 N1 N2 N3 N1
    Face by Nodes of Tria6
    Face Node 1 Node 2 Node 3 Node 4 Node 5 Node 6 Node 1
    F1 N1 N4 N2 N5 N3 N6 N1

    Quadrangle element

    FEM mesh elements 3 quadrangle.svg

    Edges of Quad4 and Quad8
    Edge Node 1 Node 2 Middle node
    E1 N1 N2 N5
    E2 N2 N3 N6
    E3 N3 N4 N7
    E4 N4 N1 N8
    Face by Edges of Quad4 and Quad8
    Face Edge 1 Edge 2 Edge 3 Edge 4
    F1 E1 E2 E3 E4
    Face by Nodes of Quad4
    Face Node 1 Node 2 Node 3 Node 4 Node 1
    F1 N1 N2 N3 N4 N1
    Face by Nodes of Quad8
    Face Node 1 Node 2 Node 3 Node 4 Node 5 Node 6 Node 7 Node 8 Node 1
    F1 N1 N5 N2 N6 N3 N7 N4 N8 N1

    Tetrahedron element

    FEM mesh elements 4 tetrahedron.svg

    Edges of Tetra4 and Tetra10
    Edge Node 1 Node 2 Middle node
    E1 N1 N2 N5
    E2 N2 N3 N6
    E3 N3 N1 N7
    E4 N1 N4 N8
    E5 N2 N4 N9
    E6 N3 N4 N10
    Faces by Edges of Tetra4 and Tetra10
    Face Edge 1 Edge 2 Edge 3
    F1 E1 E2 E3
    F2 E4 -E5 -E1
    F3 E5 -E6 -E2
    F4 E6 -E4 -E3
    Faces by Nodes of Tetra4
    Face Node 1 Node 2 Node 3 Node 1
    F1 N1 N2 N3 N1
    F2 N1 N4 N2 N1
    F3 N2 N4 N3 N2
    F4 N3 N4 N1 N3
    Faces by Nodes of Tetra10
    Face Node 1 Node 2 Node 3 Node 4 Node 5 Node 6 Node 1
    F1 N1 N5 N2 N6 N3 N7 N1
    F2 N1 N8 N4 N9 N2 N5 N1
    F3 N2 N9 N4 N10 N3 N6 N2
    F4 N3 N10 N4 N8 N1 N7 N3

    Hexahedron element

    FEM mesh elements 5 hexahedron.svg

    Edges of Hexa8 and Hexa20
    Edge Node 1 Node 2 Middle node
    E1 N1 N2 N9
    E2 N2 N3 N10
    E3 N3 N4 N11
    E4 N4 N1 N12
    E5 N5 N6 N13
    E6 N6 N7 N14
    E7 N7 N8 N15
    E8 N8 N5 N16
    E9 N1 N5 N17
    E10 N2 N6 N18
    E11 N3 N7 N19
    E12 N4 N8 N20
    Faces by Edges of Hexa8 and Hexa20
    Face Edge 1 Edge 2 Edge 3 Edge 4
    F1 E1 E2 E3 E4
    F2 -E8 -E7 -E6 -E5
    F3 E9 E5 -E10 -E1
    F4 E10 E6 -E11 -E2
    F5 E11 E7 -E12 -E3
    F6 E12 E8 -E9 -E4
    Faces by Nodes of Hexa8
    Face Node 1 Node 2 Node 3 Node 4 Node 1
    F1 N1 N2 N3 N4 N1
    F2 N5 N8 N7 N6 N5
    F3 N1 N5 N6 N2 N1
    F4 N2 N6 N7 N3 N2
    F5 N3 N7 N8 N4 N3
    F6 N4 N8 N5 N1 N4
    Faces by Nodes of Hexa20
    Face Node 1 Node 2 Node 3 Node 4 Node 5 Node 6 Node 7 Node 8 Node1
    F1 N1 N9 N2 N10 N3 N11 N4 N12 N1
    F2 N5 N16 N8 N15 N7 N14 N6 N13 N5
    F3 N1 N17 N5 N13 N6 N18 N2 N9 N1
    F4 N2 N18 N6 N14 N7 N19 N3 N10 N2
    F5 N3 N19 N7 N15 N8 N20 N4 N11 N3
    F6 N4 N20 N8 N16 N5 N17 N1 N12 N4

    Pentahedron element (prism)

    FEM mesh elements 6 pentahedron.svg

    Edges of Penta6 and Penta15
    Edge Node 1 Node 2 Middle node
    E1 N1 N2 N7
    E2 N2 N3 N8
    E3 N3 N1 N9
    E4 N4 N5 N10
    E5 N5 N6 N11
    E6 N6 N4 N12
    E7 N1 N4 N13
    E8 N2 N5 N14
    E9 N3 N6 N15
    Faces by Edges of Penta6 and Penta15
    Face Edge 1 Edge 2 Edge 3 Edge 4
    F1 E1 E2 E3 _
    F2 -E6 -E5 -E4 _
    F3 E7 E4 -E8 -E1
    F4 E8 E5 -E9 -E2
    F5 E9 E6 -E7 -E3
    Faces by Nodes of Penta6
    Face Node 1 Node 2 Node 3 Node 4 Node 1
    F1 N1 N2 N3 _ N1
    F2 N4 N6 N5 _ N4
    F3 N1 N4 N5 N2 N1
    F4 N2 N5 N6 N3 N2
    F5 N3 N6 N4 N1 N3
    Faces by Nodes of Penta15
    Face Node 1 Node 2 Node 3 Node 4 Node 5 Node 6 Node 7 Node 8 Node 1
    F1 N1 N7 N2 N8 N3 N9 _ _ N1
    F2 N4 N12 N6 N11 N5 N10 _ _ N4
    F3 N1 N13 N4 N10 N5 N14 N2 N7 N1
    F4 N2 N14 N5 N11 N6 N15 N3 N8 N2
    F5 N3 N15 N6 N12 N4 N13 N1 N9 N3

    Pyramid element

    FEM mesh elements 7 pyramid.svg

    Edges of Pyra5 and Pyra13
    Edge Node 1 Node 2 Middle node
    E1 N1 N2 N6
    E2 N2 N3 N7
    E3 N3 N4 N8
    E4 N4 N1 N9
    E5 N1 N5 N10
    E6 N2 N5 N11
    E7 N3 N5 N12
    E8 N4 N5 N13
    Faces by Edges of Pyra5 and Pyra13
    Face Edge 1 Edge 2 Edge 3 Edge 4
    F1 E1 E2 E3 E4
    F2 E5 -E6 -E1 _
    F3 E6 -E7 -E2 _
    F4 E7 -E8 -E3 _
    F5 E8 E5 -E4 _
    Faces by Nodes of Pyra5
    Face Node 1 Node 2 Node 3 Node4 Node1
    F1 N1 N2 N3 N4 N1
    F2 N1 N5 N2 _ N1
    F3 N2 N5 N3 _ N2
    F4 N3 N5 N4 _ N3
    F5 N4 N5 N1 _ N4
    Faces by Nodes of Pyra13
    Face Node 1 Node 2 Node 3 Node4 Node 5 Node 6 Node 7 Node8 Node1
    F1 N1 N6 N2 N7 N3 N8 N4 N9 N1
    F2 N1 N10 N5 N11 N2 N6 _ _ N1
    F3 N2 N11 N5 N12 N13 N7 _ _ N2
    F4 N3 N12 N5 N13 N4 N8 _ _ N3
    F5 N4 N13 N5 N10 N1 N9 _ _ N4