3.1.10.7. zeroLengthInterface2D Element

This command is used to construct a node-to-segment (NTS) interface element for 2D analysis. It can handle any number of DOFs (e.g. beam-solid, solid-solid, beam-beam contact), unlike zeroLengthContactNTS2D which is for 2 DOF nodes. The relation follows the Mohr-Coulomb law: \(T = N \times \tan(\phi)\).

element zeroLengthInterface2D $eleTag -sNdNum $sNdNum -mNdNum $mNdNum -dof $sdof $mdof -Nodes $nodeTags $kn $kt $phi

Argument

Type

Description

$eleTag

integer

unique element object tag

$sNdNum

integer

number of secondary nodes

$mNdNum

integer

number of primary nodes

$sdof $mdof

integer

secondary and primary degree of freedom

$nodeTags

list integer

secondary and primary node tags (counterclockwise order)

$kn

float

penalty in normal direction

$kt

float

penalty in tangential direction

$phi

float

friction angle in degrees

Note

  1. Secondary and primary nodes must have 2 DOF and be entered in counterclockwise order.

  2. The tangent from the contact element is non-symmetric; use a non-symmetric system solver if convergence is difficult.

  3. The contact normal is computed automatically. The element supports large deformations and different DOF types (beam-beam, beam-solid, solid-solid).

See also

Notes (OpenSees wiki)

Example

From the OpenSees wiki: element with tag 1, 6 secondary and 6 primary nodes, dof 2 and 3, node tags as listed, Kn = Kt = 1e8, friction angle 16°.

  1. Tcl Code

element zeroLengthInterface2D 1 -sNdNum 6 -mNdNum 6 -dof 2 3 -Nodes 5 10 12 3 9 11 1 4 2 8 7 6 1e8 1e8 16

  1. Python Code

ops.element('zeroLengthInterface2D', 1, '-sNdNum', 6, '-mNdNum', 6, '-dof', 2, 3, '-Nodes', 5, 10, 12, 3, 9, 11, 1, 4, 2, 8, 7, 6, 1e8, 1e8, 16)

References: Wriggers, P., Computational Contact Mechanics, John Wiley & Sons, 2002.

Code developed by: Roozbeh G. Mikola, UC Berkeley and N. Sitar, UC Berkeley