3.1.5.21. SLModel Material

This command is used to construct a material based on the Suzuki and Lignos model.

uniaxialMaterial SLModel $Mat_Tag $Dt $E $sigma_y $C $gamma $QInf $b $sigma_c0 $epsilon_c0 $Ed1 $Ed2 $sigma_dm $aSigma $aE $Lambda $c

Argument	Type	Description (Units)
$matTag	integer	Integer tag identifying material (-)
$Dt	float	Section slenderness D/t (-)
$E	float	Young’s modulus (MPa)
$sigma_y	float	Initial yield stress (MPa)
$C	float	Kinematic hardening parameter (MPa)
$gamma	float	Saturation rate of kinematic hardening (-)
$QInf	float	Isotropic hardening parameter (MPa)
$b	float	Saturation rate of isotropic hardening (-)
$sigma_c0	float	Initial capping stress (MPa)
$epsilon_c0	float	Initial capping strain (-)
$Ed1	float	First softening slope (MPa)
$Ed2	float	Second softening slope (MPa)
$sigma_dm	float	Stress at local buckling wave length stabilization (MPa)
$aSigma	float	Cyclic deterioration parameter for yield stress (-)
$aE	float	Cyclic deterioration parameter for unloading stiffness (-)
$Lambda	float	Reference cumulative strain capacity (-)
$c	float	Parameter defining the rate of cyclic deterioration (-)

Note

The stresses and strains model parameters (for both tension and compression) should be specified as positive values.

(-) means that the parameter is unitless

[SuzukiAndLignos2020]

Suzuki, Y., Lignos, D. G. (2020). “Fiber-based hysteretic model for simulating strength and stiffness deterioration of steel hollow structural section columns under cyclic loading.” Earthquake Engineering & Structural Dynamics 49 (15): 1702–20. https://doi.org/10.1002/eqe.3324.

Fig. 3.1.5.15 SLModel monotonic and cyclic curves

Fig. 3.1.5.16 SLModel sample responses and validations

Fig. 3.1.5.17 SLModel validation within a beam-column element

Example

The following code is used to construct a SLModel material using SI units.

set Dt 25.; #(-)
set E 200000; #(MPa)
set sigma_y 325.; #(MPa)
set C 4200.; #(MPa)
set gamma 19.; #(-)
set QInf 68.1; #(MPa)
set b 14.1; #(-)
set sigma_c0 399.6; #(MPa)
set epsilon_c0 0.0132; #(-)
set Ed1 -4330.7; #(MPa)
set Ed2 -543.4; #(MPa)
set sigma_dm 249.1; #(MPa)
set aSigma 0.043; #(-)
set aE 0.021; #(-)
set Lambda 0.83; #(-)
set c 1.; #(-)

uniaxialMaterial SLModel 1 $Dt $E $sigma_y $C $gamma $QInf $b $sigma_c0 $epsilon_c0 $Ed1 $Ed2 $sigma_dm $aSigma $aE $Lambda $c;

For code inquires or bug reporting, please contact: - Diego Heredia, Ecole Polytechnique Federale Lausanne (EPFL), e-mail: diego.herediarosa@epfl.ch

For more information visit: https://www.epfl.ch/labs/resslab/