3.1.10.8. zeroLengthImpact3D Element

This command constructs a node-to-node zero-length contact element in 3D to simulate impact/pounding and friction. It extends zeroLengthContact3D with ImpactMaterial-style behavior (Hertz impact model). The element is fast-converging and can be used for surface-to-surface contact by connecting nodes on the constrained surface to nodes on the retained surface.

element zeroLengthImpact3D $eleTag $cNode $rNode $direction $initGap $frictionRatio $Kt $Kn $Kn2 $Delta_y $cohesion

Argument	Type	Description
$eleTag	integer	unique element object tag
$cNode $rNode	integer	constrained and retained node tags
$direction	integer	out-normal of master plane: 1 = +X, 2 = +Y, 3 = +Z
$initGap	float	initial gap between master and slave
$frictionRatio	float	friction ratio in tangential directions
$Kt	float	penalty in tangential directions
$Kn	float	penalty in normal direction
$Kn2	float	penalty in normal direction after yielding (Hertz)
$Delta_y	float	yield deformation (Hertz impact model)
$cohesion	float	cohesion (zero if none)

Note

1. End nodes should be in a 3 DOF domain. See OpenSees documentation and forums for using 3 DOF and 6 DOF together (example scripts are on the wiki).

2. This element is built on zeroLengthContact3D; all notes for that element apply (retained/constrained nodes, DOF, etc.).

3. The tangent is non-symmetric; use a non-symmetric solver if needed.

See also

Notes (OpenSees wiki), ZeroLengthContact, ImpactMaterial

Example

The following constructs a zeroLengthImpact3D element with tag 1 between constrained node 2 and retained node 4, normal in +Z, zero gap, friction 0.3, penalties 1e6 (Kt, Kn), Kn2 = 2e6, Delta_y = 0.001, zero cohesion.

1. Tcl Code

element zeroLengthImpact3D 1 2 4 3 0.0 0.3 1e6 1e6 2e6 0.001 0.0

2. Python Code

ops.element('zeroLengthImpact3D', 1, 2, 4, 3, 0.0, 0.3, 1e6, 1e6, 2e6, 0.001, 0.0)

Code developed by: Dr. Arash E. Zaghi and Majid Cashany, University of Connecticut (UConn)