tet4

The tet4 element defines a 4-noded thetrahedral element.

Stiffness Matrix

The local stiffness matrix, defined by the integral \(\mathbf{K}_{e} = \int_{V_{e}} \mathbf{B}^{T} \mathbf{D} \mathbf{B} dV\), is computed exactly with the node coordinates of the element [Zienkiewicz and Taylor, 2000]. The elasticity matrix \(\mathbf{D}\) is constant over the element.

Input Notes

• In the input file topol_list must be set the element type ELE_TYPE = 1.

• In the input file topol_file must be set for each element : the element index ELE_IND, the material index ELE_MAT and the nodal connections ELE_CON[NC_TYPE] with NC_TYPE = 4.

• The nodal connections can have any sorting.

• The parameters needed to assembly \(\mathbf{D}\) are defined by the material related to MAT_TYPE[ELE_MAT] index (see topol_file and materials input files).

Output Notes

• The output stress tensor in the out.DistStress file is exactly the stress tensor of the element.