KikuchiAikenLRB Material

• Command_Manual
  • Tcl Commands
  • Modeling_Commands
    • model
    • uniaxialMaterial
    • ndMaterial
    • frictionModel
    • section
    • geometricTransf
    • element
    • node
    • sp commands
      • fix
      • fixX
      • fixY
      • fixZ
    • mp commands
      • equalDOF
      • rigidDiaphragm
      • rigidLink
    • timeSeries
    • pattern
    • mass
    • block commands
      • block2D
      • block3D
    • region
    • rayleigh
  • Analysis Commands
    • constraints Command
    • numberer Command
    • system Command
    • test Command
    • algorithm Command
    • integrator Command
    • analysis Command
    • eigen Command
    • analyze Command
  • Output Commands
    • recorder
    • record
    • print
    • printA
    • logFile
    • RealTime_Output_Commands
  • Misc Commands
    • eleResponse Command
    • getTime Command
    • getEleTags Command
    • getNodeTags
    • loadConst Command
    • nodeCoord Command
    • nodeDisp Command
    • nodeVel Command
    • nodeAccel Command
    • nodeEigenvector Command
    • nodeBounds
    • print Command
    • remove Command
    • reset Command
    • testIter
    • testNorms
    • wipe Command
    • exit Command
  • DataBase Commands
    • Template:DataBaseCommandsMenu

---

This command is used to construct a uniaxial KikuchiAikenLRB material object. This material model produces nonlinear hysteretic curves of lead-rubber bearings.

uniaxialMaterial KikuchiAikenLRB $matTag $type $ar $hr $gr $ap $tp $alph $beta <-T $temp> <-coKQ $rk $rq> <-coMSS $rs $rf>

---

$matTag	integer tag identifying material
$type	rubber type (see note 1)
$ar	area of rubber [unit: m^2]
$hr	total thickness of rubber [unit: m]
$gr	shear modulus of rubber [unit: N/m^2]
$ap	area of lead plug [unit: m^2]
$tp	yield stress of lead plug [unit: N/m^2]
$alph	shear modulus of lead plug [unit: N/m^2]
$beta	ratio of initial stiffness to yielding stiffness
$temp	temperature [unit: °C]
$rk $rq	reduction rate for yielding stiffness ($rk) and force at zero displacement ($rq)
$rs $rf	reduction rate for stiffness ($rs) and force ($rf) (see note 3)

NOTES:

1) Following rubber types for $type are available:

1	lead-rubber bearing, up to 400% shear strain [Kikuchi et al., 2010 & 2012]

2) This material uses SI unit in calculation formula. Input arguments must be converted into [m], [m^2], [N/m^2].

3) $rs and $rf are available if this material is applied to multipleShearSpring (MSS) element. Recommended values are $rs=1/sum(i=0,n-1){ sin(pi*i/n)^2} and $rf=1/sum(i=0,n-1){sin(pi*i/n)}, where n is the number of springs in the MSS. For example, when n=8, $rs=0.2500 and $rf=0.1989.

---

EXAMPLE:

KikuchiAikenLRB_sample.tcl

REFERENCES:

M. Kikuchi, T. Nakamura, I. D. Aiken, "Three-dimensional analysis for square seismic isolation bearings under large shear deformations and high axial loads", Earthquake Engineering and Structural Dynamics, Vol. 39, 1513-1531, 2010.

M. Kikuchi , I. D. Aiken, 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