KikuchiBearing Element

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This command is used to construct a KikuchiBearing element object, which is defined by two nodes. This element consists of multiple shear spring model (MSS) and multiple normal spring model (MNS).

element KikuchiBearing $eleTag $iNode $jNode -shape $shape -size $size $totalRubber <-totalHeight $totalHeight> -nMSS $nMSS -matMSS $matMSSTag <-limDisp $limDisp> -nMNS $nMNS -matMNS $matMNSTag <-lambda $lambda> <-orient <$x1 $x2 $x3> $yp1 $yp2 $yp3> <-mass $m> <-noPDInput> <-noTilt> <-adjustPDOutput $ci $cj> <-doBalance $limFo $limFi $nIter>

$eleTag unique element object tag
$inode $jnode end nodes
$shape following shapes are available: round, square
$size diameter (round shape), length of edge (square shape)
$totalRubber total rubber thickness
$totalHeight total height of the bearing (defaulut: distance between iNode and jNode)
$nMSS number of springs in MSS = nMSS
$matMSSTag matTag for MSS
$limDisp minimum deformation to calculate equivalent coefficient of MSS (see note 1)
$nMNS number of springs in MNS = nMNS*nMNS (for round and square shape)
$matMNSTag matTag for MNS
$lambda parameter to calculate compression modulus distribution on MNS (see note 2)
$x1 $x2 $x3 vector components in global coordinates defining local x-axis
$yp1 $yp2 $yp3 vector components in global coordinates defining vector yp which lies in the local x-y plane for the element
$m element mass
-noPDInput not consider P-Delta moment
-noTilt not consider tilt of rigid link
$ci $cj P-Delta moment adjustment for reaction force (default: $ci=0.5, $cj=0.5)
$limFo $limFi $nIter tolerance of external unbalanced force ($limFo), tolorance of internal unbalanced force ($limFi), number of iterations to get rid of internal unbalanced force ($nIter)


1) If $limdisp is positive and the shear deformation of MSS exceeds $limdisp, this element calculates equivalent coefficient to adjust force and stiffness of MSS. The adjusted MSS force and stiffness reproduce the behavior of the previously defined uniaxial material under monotonic loading in every direction.

2) Recommended value is (D/t)*sqrt(3*G/K), where D, t, G and K are size (for round and square shape), thickness, shear modulus and bulk modulus of a rubber layer, respectively.

3) The valid queries to a KikuchiBearing element when creating an ElementRecorder object are 'globalForce', 'localForce', 'basicForce', 'localDisplacement' and 'basicDeformation'.

KikuchiBearing Model.png


element KikuchiBearing 1 1 2 -shape round -size 1.016 0.320 -nMSS 8 -matMSS 1 -nMNS 30 -matMNS 2

KikuchiBearing_Sample.tcl, KikuchiBearing_input_Z.tcl, KikuchiBearing_input_X.tcl

case 1: P-Delta effect not considered (use -noPDInput -noTilt option)
case 2: P-Delta effect considered, uniform distribution of compression modulus
case 3: P-Delta effect considered (use -lambda option)

KikuchiBearing ForceDeformation case1 v2.png       KikuchiBearing ForceDeformation case2 v2.png       KikuchiBearing ForceDeformation case3 v2.png


M. Kikuchi , I. D. Aiken and A. Kasalanati , "Simulation analysis for the ultimate behavior of full-scale lead-rubber seismic isolation bearings", 15th World Conference on Earthquake Engineering, No. 1688, 2012.

Code Developed by: mkiku