material behaviour modeling-comression and tension

[hani.akkari]

Dear Support Team,

I'm facing one problem in my research, i'm studying the performance of concentrically steel braced frames under seismic loading,the problem is the following : I need to model the S truss element with bilinear material model that behaves in compression( after buckling , Fy will be decreased to Fr(residual)) different from its behaviour in tension(Fy). so is it possible to do it with seismostruct?

Regards,

Hani.

[huffte]

It might be that a link-type, bilinear asymmetric element would do the trick Hani. It's worth looking into anyway, to see if you can come up with the appropriate values for each parameter to mimic your truss member. Another option might be the tri-linear asymmetric curve applied to a link-type element.

Best of luck Hani.

[hani.akkari]

Dear huffte,
thanks for your reply, actually i want to check with you 2 points :

1- in the material page , i have remarked the presence of a table of time and strain, is it possible to generate a material which has the yield strength in tension different from that in compression.?

2- in your reply you mentioned the possibility of using link element to mimic the postbuckling behavior of material, so if we succeed to force the link to behave as i wish, what will be the attitude of the hole bracing memeber? does the memeber inherit the required behavior from the link?

regards,

Hani

[seismosoft]

Hi,

1) no, there is currently no bilinear material model in SeismoStruct with different behaviour in tension and compression. You may, however consider employing the 'stl_mn' model, which is not necessarily bilinear, but indeed capable of considering buckling

2) no, a frame element adjacent to a link one does not inherit the behaviour of the link. However, the forces/deformations transmitted to the frame element depend on the response of the adjacent link, and hence you end up by being able to simulate the response you had in mind, through this workaround

Seismosoft Support