4.14.5.29. KikuchiAikenLRB Material¶

uniaxialMaterial('KikuchiAikenLRB', matTag, type, ar, hr, gr, ap, tp, alph, beta, <'-T', temp>, <'-coKQ', rk, rq>, <'-coMSS', rs, rf>)

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

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

Note

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