Modeling of asymmetric hysteresis material

[Matti]

According to bellow picture, I want to model an Ibarra-Krawinkler hysteretic material for an infill compressive strut:

http://uupload.ir/files/jqr8_strut_matrial.jpg

When I used "uniaxialMaterial Hysteretic" material, this error apeared:
"HystereticMaterial::HystereticMaterial -- input backbone is not unique (one-to-one)"

On the other hand, "uniaxialMaterial ModIMKPinching" doesn't consider the pinching factor for strain (kd) and "uniaxialMaterial Pinching4" material is very complicated.

Now, what is the solution?
How can model an asymmetric hysteresis material with pinching parameters (kd and kf) in Opensees?

[ashf]

I've gotten this error already,because the value of second strain should be bigger than first strain,third strain should be bigger than second strain.

[Matti]

ashf wrote:
> I've gotten this error already,because the value of second strain should be
> bigger than first strain,third strain should be bigger than second strain.

Thank you for the solution . The problem was solved

[AngusHunter]

Hi Friends,
I am using this Hysteretic Uniaxial Material, but I always get the reply: HystereticMaterial::HystereticMaterial -- input backbone is not unique (one-to-one)

Here is my codes. I don't really know why it is wrong. The second strain is smaller than the first one? I don't think so......

uniaxialMaterial Hysteretic 1105 129171 0.004 173792 0.01 -129171 -0.004 -129171 -0.004 0.25 0.25 0.0 0.0

THANKS a lot!

[selimgunay]

Please try

uniaxialMaterial Hysteretic 1105 129171 0.004 173792 0.01 -129171 -0.004 -129171 -0.00405 0.25 0.25 0.0 0.0

[AngusHunter]

selimgunay wrote:
> Please try
>
> uniaxialMaterial Hysteretic 1105 129171 0.004 173792 0.01 -129171 -0.004 -129171 -0.00405 0.25 0.25 0.0 0.0


Thank you so much!
Can I ask why "-0.004" is changed to "-0.00405"?
Because I have many similar lines of code should be changed like this.
THANK YOU!

[selimgunay]

Because the strains in consecutive points should go in an increasing order.