KikuchiAikenLRB

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: &deg;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]

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

      1. 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(pii/n)^2} and rf=1/sum(i=0,n-1){sin(pii/n)}, where n is the number of springs in the MSS. For example, when n=8, $rs=0.2500 and $rf=0.1989.


Examples

KikuchiAikenLRB_sample.tcl

KikuchiAikenLRB_ForceStrain.png

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

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