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: °C] |
|
reduction rate for yielding stiffness ( |
|
reduction rate for stiffness ( |
NOTES:
- Following rubber types for
type
are available:1
lead-rubber bearing, up to 400% shear strain [Kikuchi et al., 2010 & 2012]
- This material uses SI unit in calculation formula. Input arguments must be converted into [m], [m^2], [N/m^2].
rs
andrf
are available if this material is applied to multipleShearSpring (MSS) element. Recommended values arers
=1/sum(i=0,n-1){ sin(pii/n)^2} andrf
=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.
- This material uses SI unit in calculation formula. Input arguments must be converted into [m], [m^2], [N/m^2].
Examples

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