problem using Bilin material

[omidgahremani]

In defining bilin material there are four parameters known as cyclic deterioration parameters (Lamda_S,Lamda_C,Lamda_A,Lamda_K) that I don't know the correct values that must be assigned to them.
I studied the corresponding references , but there is only one Lamda parameter that is around 1 according to given equation and in another on of references there is four cyclic deterioration parameter named as Omega_S,Omega_C,Omega_A and Omega_K that have values more than 25.
nominally these are different parameters but I think I should use these parameter's values instead of the so called Lamda's in Bilin material parameters.
I am looking forward for your instruction.
thanks for your attention and kind help.

[fmk]

I asked the author, he suggested keeping all the same. here is his reply:

"All the Lamda parameters are based on the paper by Lignos and Krawinkler (2011). As discussed in the paper all 4 Lamda parameters are equal for simplicity; else the calibration process becomes complicated. The equation proposed by Lignos and Krawinkler (2011) is sufficient to compute Lamda."

I would post it but I don’t have my login access info.

Best Regards,

Dimitrios

[omidgahremani]

thanks a lot.

[omidgahremani]

I appreciate your help.
could you give me the name of referred paper "Lignos and Krawinkler (2011)" ?

[fmk]

look at the references, number 8:
http://opensees.berkeley.edu/wiki/index ... aterial%29