3.1.5.2. Steel02 Material

This command is used to construct a uniaxial Giuffre-Menegotto-Pinto steel material object with isotropic strain hardening.

uniaxialMaterial Steel02 $matTag $Fy $E $b $R0 $cR1 $cR2 <$a1 $a2 $a3 $a4 $sigInit>

Argument	Type	Description
$matTag	integer	integer tag identifying material
$Fy	float	yield strength
$E0	float	initial elastic tangent
$b	float	strain-hardening ratio (ratio between post-yield tangent and initial elastic tangent)
R0 $CR1 $CR2	3 float	parameters to control the transition from elastic to plastic branches.
$a1	float	isotropic hardening parameter. (optional: default = 0.0). see note.
$a2	float	isotropic hardening parameter (optional: default = 1.0). see note.
$a3	float	isotropic hardening parameter. (optional: default = 0.0). see note.
$a4	float	isotropic hardening parameter. (optional: default = 1.0). see note.
$sigInit	float	Initial Stress Value (optional: default = 0.0)

Note

$a1 and $a2: increase of compression yield envelope as proportion of yield strength after a plastic strain of $a2*($Fy/E0).

$a3 and $a4: increase of tension yield envelope as proportion of yield strength after a plastic strain of $a4*($Fy/E0).

Recommended values: $R0=between 10 and 20, $cR1=0.925, $cR2=0.15

If $siginit is specified, strain is calculated from epsP=$sigInit/$E

if (sigInit!= 0.0) {
   double epsInit = sigInit/E;
   eps = trialStrain+epsInit;
} else {
   eps = trialStrain;
}

[FilippouEtAl1983]

Filippou, F. C., Popov, E. P., Bertero, V. V. (1983). “Effects of Bond Deterioration on Hysteretic Behavior of Reinforced Concrete Joints”. Report EERC 83-19, Earthquake Engineering Research Center, University of California, Berkeley.

Fig. 3.1.5.5 Steel02 Material – Material Parameters of Monotonic Envelope

Fig. 3.1.5.6 Steel02 Material – Default Hysteretic Behavior (NO isotropic hardening)

Example

The following is used to construct a Steel02 mataerial with a tag of 1, a yield strength of 60.0 and an initial tangent stiffness of 30000,0.

1. Tcl Code

uniaxialMaterial Steel02 1 60.0 30000.0 0.1 20.0 .925 .15

2. Python Code

uniaxialMaterial('Steel02',1,60.0,30000.0, 0.1, 20.0, .925, .15)

Code Developed by: Michael H. Scott