FourNodeTetrahedron

Tet.png

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

Examples

References

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

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