FourNodeTetrahedron

• Command_Manual
  • Tcl Commands
  • Modeling_Commands
    • model
    • uniaxialMaterial
    • ndMaterial
    • frictionModel
    • section
    • geometricTransf
    • element
    • node
    • sp commands
      • fix
      • fixX
      • fixY
      • fixZ
    • mp commands
      • equalDOF
      • rigidDiaphragm
      • rigidLink
    • timeSeries
    • pattern
    • mass
    • block commands
      • block2D
      • block3D
    • region
    • rayleigh
  • Analysis Commands
    • constraints Command
    • numberer Command
    • system Command
    • test Command
    • algorithm Command
    • integrator Command
    • analysis Command
    • eigen Command
    • analyze Command
  • Output Commands
    • recorder
    • record
    • print
    • printA
    • logFile
    • RealTime_Output_Commands
  • Misc Commands
    • eleResponse Command
    • getTime Command
    • getEleTags Command
    • getNodeTags
    • loadConst Command
    • nodeCoord Command
    • nodeDisp Command
    • nodeVel Command
    • nodeAccel Command
    • nodeEigenvector Command
    • nodeBounds
    • print Command
    • remove Command
    • reset Command
    • testIter
    • testNorms
    • wipe Command
    • exit Command
  • DataBase Commands
    • Template:DataBaseCommandsMenu

---

This command is used to construct a standard four-node tetrahedron element objec with one-point Gauss integration.

element FourNodeTetrahedron $eleTag $node1 $node2 $node3 $node4 $matTag <$b1 $b2 $b3>

---

$eleTag	unique element object tag
$node1 $node2 $node3 $node4	four nodes defining element boundaries, input order is shown in the figure.
$matTag	tag of nDMaterial
'$b1 $b2 $b3	body forces in global x,y,z directions

Because sometimes bricks will give you headaches! Use this if you don't care much about the stress/strain fields (tets are notoriously bad). Otherwise, you can use the 10-node quadratic tetrahedron (in development).

NOTE:

1. The valid queries to a FourNodeTetrahedron element when creating an ElementRecorder object are 'forces', 'stresses,' ('strains' version > 2.2.0) and 'material $matNum matArg1 matArg2 ...' Where $matNum refers to the material object at the integration point corresponding to the node numbers in the isoparametric domain.
2. This element can only be defined in -ndm 3 -ndf 3

EXAMPLE:

REFERENCES:

Carlos Felipa's AFEM Course: Chapter 9 The Linear Tetrahedron.

---

Code Developed by José A. Abell at Universidad de los Andes, Chile