problem on the steel02

[lkang6]

Hi, I have a problem on steel02

I defined a material for an element as following:
uniaxialMaterial Steel02 300 80998 29080222 0.005 18.5 0.925 0.15
and applied cyclic loading on this element. But the the hysteretic stress-strain curve of this material is almost symmetric in positive and negtive direction, not like the figure in the'Figure 31: Steel02 Material -- Hysteretic Behavior of Model w/o Isotropic Hardening', which Bauschinger effect is obvious.

Could you please tell what is the problem of my definition, and how can i define the material, so the Bauschinger effect is obvious??

Thank you so much!

[vesna]

The way you defined it looks good to me. Apply large displacement on your element if you want to see Bauschinger effect better. If you still do not like it look at the reference paper for Steel02 to see how to change material parameters to get what you want.

[tazarv]

I have modeled your Steel02 uniaxial material under cyclic analysis. Here is a link to see the hysteretic behavior of what you have modeled.
http://i52.tinypic.com/2d1aff8.jpg
I don't know what was you unit, however that's stress-strain of your Steel02.

Bests,

[lkang6]

Thank you guys^^

[rasoulazadi]

hi dear vesna
i want to define steel02 material
the unit of Fy and E should be kg/cm^2 or N/cm^2
my gravity loads are at unit of kg and eleloads are at unit of N (newton)
tanks

[vesna]

what is your question?

[mnazari]

Hi,
I have modeled a rotational spring at the base of a rocking wall, using zero-length element, like: "element zeroLength 1 1 2 -mat 3 -dir 6 -doRayleigh 1"
For the material (-mat 3) I am using two parallel springs: One of them represents a type of steel connector which is going to model the hysteresis behavior of the system. So, I selected STEEL 02 to model this spring. To use related command, "uniaxialMaterial Steel02 $matTag $Fy $E $b $R0 $cR1 $cR2 <$a1 $a2 $a3 $a4 $sigInit>" I need to plug the Fy and E value. Since this spring should model the "rotational behavior" of the system, is it correct that I use "My" instead of Fy and (yielding moment /yielding rotation) as E? For the other spring I am also using a multilinear elastic material but instead of strain-stress or (force-displacement) data I used moment-rotation data.
Does it make sense?
Really appreciate if you respond me asap.

[vesna]

Yes, your approach is correct. When defining a rotational spring the input for the material is in moment-rotation format.

[mnazari]

Thanks Vesna,

[mnazari]

Hello,

I am modelling an unbonded post-tensioned tendon in a concrete wall with a truss element using Steel02 material, with an initial stress of 69.2 ksi:
set initStress 69.2
"uniaxialMaterial Steel02 $PT 245.0 [expr (245.0/0.0086)] [expr (((270.0-245.0)/(0.04-0.0086))/(245.0/0.0086))] 18 0.925 0.15 0 1 0 1 $initStress"

During base excitation tendons yielded (stress>245 ksi) and initial stress (69.2 ksi) dropped to almost 15 ksi. After yielding of tendons and for the rest of the motion, stress in tendons change from this 15 ksi! I am not sure if this is the best way to model PT tendons while yielding takes place and if so, how can I control the PT loss using Steel02 material.

Thanks a lot!