modeling SMA braces in 6story steel frame

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raminmrd
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Joined: 04 Sep 2020, 11:48

modeling SMA braces in 6story steel frame

Post by raminmrd »

how can i model SMA braces in steel frame???????
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seismosoft
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Re: modeling SMA braces in 6story steel frame

Post by seismosoft »

You may use the SMA material model (instead of steel) with one of the sections from SeismoStruct's sections library.
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FarzinPhD
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Joined: 08 Sep 2020, 19:03

Re: modeling SMA braces in 6story steel frame

Post by FarzinPhD »

Hi, i plan to model 3 story 1 bay steel 2D frame and i want to add X SMA braces in model. After it, i want to do dynamic time history analysis.
1st question: in SMA braces which one forces should be released? (M2a,b or M3a,b or F or Mt)?
2nd question: in the Beams are the any force release needed?
3rd question: if i want to draw axial force - displacement curve for one of the SMA braces, how i can do this action?
(My model have acceleration load in Y direction and nodal force in -Z direction).
Please any one help me.
Please give your frank answer.
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seismosoft
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Re: modeling SMA braces in 6story steel frame

Post by seismosoft »

1) It depends on the connection of your brace system
2) Again, It depends on your structural configuration, but probably not
3) You can get all the action effects (e.g. axial loads, strain) from the post-processor. You could also set stress points to follow the stress strain history at specific locations of the cross section
In any case however note that all these issues are not related to the use of the program strictly speaking, hence they must probably be discussed with yuor supervisor.
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roshen.rj
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Joined: 10 Feb 2020, 07:57

Re: modeling SMA braces in 6story steel frame

Post by roshen.rj »

seismosoft wrote: 10 Sep 2020, 12:25 1) It depends on the connection of your brace system
2) Again, It depends on your structural configuration, but probably not
3) You can get all the action effects (e.g. axial loads, strain) from the post-processor. You could also set stress points to follow the stress strain history at specific locations of the cross section
In any case however note that all these issues are not related to the use of the program strictly speaking, hence they must probably be discussed with yuor supervisor.
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I am also working on a similar research on SMA braces in a 2 story RC frame. However, I am trying to use the SMA model as a link element in the brace and not in the sections. I started with the static pushover analysis and it seemed initially that the parameter for the SMA model was high and hence I had to reduced it. I was able to get a suitable pushover curve. However, when it came to running the dynamic time history analysis, it starts to fail at PGA only 3 times the design intensity which deems the building model as weak.
roshen.rj
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Joined: 10 Feb 2020, 07:57

Re: modeling SMA braces in 6story steel frame

Post by roshen.rj »

What can be a suitable suggestion to make the model running? As it works in one type of analysis (static pushover) but not in the dynamic time history.
roshen.rj
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Re: modeling SMA braces in 6story steel frame

Post by roshen.rj »

The error that I get in between the processor stage of the time history analysis is : Prd_Ite and Adp_Cnv meaning that it does not converge
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seismosoft
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Re: modeling SMA braces in 6story steel frame

Post by seismosoft »

From the structure of SeismoStruct, it is not possible to use a material model to calibrate link elements. You need to employ one of the available response curves.
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roshen.rj
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Re: modeling SMA braces in 6story steel frame

Post by roshen.rj »

seismosoft wrote: 20 Oct 2020, 14:03 From the structure of SeismoStruct, it is not possible to use a material model to calibrate link elements. You need to employ one of the available response curves.
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I do not understand. So what is the purpose of 'scb' curve type under link element in the 'Element Classes'. As I said that this is the option I have used and this link element is part of my brace to replicate the SC Bracing behaviour.
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seismosoft
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Re: modeling SMA braces in 6story steel frame

Post by seismosoft »

Indeed the scb response curve is appropriate for the link element. I thought that you meant that you were trying to use the SMA material model with the link element. Regarding the convergence problems that you face, carry out a search for 'convergence', you will find numerous posts. Specifically for the link element, make sure that all DOFs are fixed. An eigenvalue analysis might give you valuable insignt
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