Need material help

[grahamo]

I am modeling a Buckling-Restrained brace frame. I am using a corotTruss element since I understand that the truss element will not buckle. To do this I need a trilinear hysteretic material that doesn't have degradation.

I have tried using the Hysteretic material but the stress strain plot doesn't perform as expected in compression. After unloading in the tension area it doesn't load the same in the compression area. Here is the code that I was using for the hysteretic material:

Code: Select all

uniaxialMaterial Hysteretic $BraceMat $s1p $e1p $s2p $e2p $s3p $e3p -$s1p -$e1p -$s2p -$e2p -$s3p -$e3p $pinchX $pinchY $damage1 $damage2

I also tried the Steel02 material but I don't fully understand what it is doing and it will be difficult to mimic the correct response. Here is a plot of the Steel02 plot.

Does anyone have any suggestions on how to get BRB materials to work correctly?

Also, of note, to get the stress and strain response I had to not specify the matID.

Code: Select all

recorder Element -file "$dataDir/$FileName/$ii/ElemMatStress$level Eq[expr $num+1].out" -time -ele $elemID material stress

Thanks.

[silvia]

you might want to research the work on this.
Patxi Uriz (or switch the x and z) has done with using two trusses with an initial eccentricity....