Bouc-Wen model

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hnxiaye
Posts: 2
Joined: Thu Apr 22, 2010 12:46 pm
Location: Univ. of California, Irvine

Bouc-Wen model

Post by hnxiaye » Thu Apr 22, 2010 1:42 pm

[quote="AURELIO"]Help!
I need to model a structural frame element, instead of SDOF or shear beam, using Bouc-Wen model. It means I need to couple material nonlinearity (Bouc-Wen model) into local stiffness element of all the frame members and assemble them.
I have problem to write the local stiffness element, is it still symmetric?
Has someone ideas or useful scripts? It probably has been done already.

Dear Silvia, could you help me?
Thank you in advance.
Ye

fmk
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Post by fmk » Thu Apr 22, 2010 3:52 pm

why are you placing this in useful scripts? .. as for your problem, you cannot put it in the ocal stiffness matrix of elements w/o wri[i]ng some c++ code .. you could place it in the global stiffness matrix by adding some zerolength elements between beam end nodes and placing your material acting in the dirn you want .. this will add terms to appropriate parts of global stiffness matrix.[/i]

hnxiaye
Posts: 2
Joined: Thu Apr 22, 2010 12:46 pm
Location: Univ. of California, Irvine

Post by hnxiaye » Fri Apr 23, 2010 8:52 am

Thanks a lot fmk.

Indeed, I don't need to work on the local stiffness matrix but only global one.

Specifically for Bouc-Wen model, I guess what I need to do is like this: write down the global stiffness matrix first, then modify it by multiplying *alpha_1* (Bouc-Wen model parameter corresponding with DOF 1) to column 1, *alpha_2* to column 2 and *alpha_n* to column n. Then imaginary displacement Z (for example, z_1) would be defined according to DOF 1 related Bouc-Wen parameters. Am I right? I am not quite sure.

This is not so much related to C++, but just the theory of nonlinear model. What I originally want to do is to get a implemented scripts and figure out how they write the Equation of Motion.

Thanks again.
Ye

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