ZeroLengthImpact3D

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This command constructs a node-to-node zero-length contact element in 3D space to simulate the impact/pounding and friction phenomena.

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

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$tag	Unique element object tag
$cNode	Constrained node tag
$rNode	Retained node tag
$direction	1 if out-normal vector of master plane points to +X direction 2 if out-normal vector of master plane points to +Y direction 3 if out-normal vector of master plane points to +Z direction
$initGap	Initial gap between retained plane and constrained plane
$frictionRatio	Friction ratio in two tangential directions (parallel to retained and constrained planes)
$Kt	Penalty in two tangential directions
$Kn	Penalty in normal direction (normal to retained and constrained planes)
$Kn2	Penalty in normal direction after yielding based on Hertz impact model
$Delta_y	Yield deformation based on Hertz impact model
$cohesion	Cohesion, if no cohesion, it is zero

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NOTES:

1. This element has been developed on top of the “zeroLengthContact3D”. All the notes available in “zeroLengthContact3D” wiki page would apply to this element as well. It includes the definition of retained and constrained nodes, the number of degrees of freedom in the domain, etc.
2. Regarding the number of degrees of freedom (DOF), the end nodes of this element should be defined in 3DOF domain. For getting information on how to use 3DOF and 6DOF domain together, please refer to OpenSees documentation and forums or see the zip file provided in the EXAMPLES section below.
3. This element adds the capabilities of “ImpactMaterial” to “zeroLengthContact3D.”
4. For simulating a surface-to-surface contact, the element can be defined for connecting the nodes on constrained surface to the nodes on retained surface.
5. The element was found to be fast-converging and eliminating the need for extra elements and nodes in the modeling process.

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EXAMPLES:

1. The following zip file contains an example script and the corresponding input cyclic displacement: File:Example script 2.zip
2. The following zip file contains an example script on how to use 6DOF domain and 3DOF domain together: File:Example script 6DOF 3DOF.zip

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REFERENCES:

zeroLengthContact3D , ImpactMaterial

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CODE DEVELOPED BY:

Dr. Arash E. Zaghi and Majid Cashany at University of Connecticut (UConn)

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APPLICATIONS:

1. This element has been employed to simulate the bridge hinges including superstructure-abutment interaction at the University of Connecticut (UConn) and University of Nevada, Reno (UNR).
2. It has been implemented in non-structural systems like suspended ceilings, simulating the impact/pounding and friction phenomena.