CoupledZeroLength

This command is used to construct a CoupledZeroLength element object, which is defined by two nodes at the same location. The nodes are connected a single UniaxialMaterial element to represent the force-deformation relationship for the element in a 2d plane. Unlike a ZeroLength element which can only provide a rectangular force interaction surface in a 2d plane, this element provides a circular force interaction surface.

element CoupledZeroLength $eleTag $iNode $jNode $dirn1
        $dirn2 $matTag <$rFlag>

eleTag

unique element object tag

iNode jNode

end nodes

matTag

tags associated with previously-defined UniaxialMaterial

dir1 dir2

the two directions, 1 through ndof.

rFlag

optional, default = 0

rFlag = 0 NO RAYLEIGH DAMPING (default)

rFlag = 1 include rayleigh damping

NOTE:

The valid queries to a zero-length element when creating an ElementRecorder object are ‘force,’ and ‘material matArg1 matArg2 …’

Examples

element CoupledZeroLength 1 2 4 5 6 7; # truss tag 1 between nodes 2 and 4 acting in directions 5 and 6 with material 7.


Theory

if change in element end displacements for 2 dof of interest are d1 and d2:

the deformation (strain in uniaxial material) of the material is set to be:

<math>= sqrt( ^2 + ^2)</math>

and if resulting force (stress from uniaxial material) is Sigma then the force computed for the two directions 1 and 2 are:

<math> F_1 = () / </math> <math> F_2 = () / </math>

NOTE: in case where \(\epsilon = 0.0\), the forces are computed using \(\Sigma\) and the last committed set of displacements that were not zero.


Code Developed by: fmk

Back to top