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Re: problem with sap2000 on nonlinear dynamic analysis.

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> I really can't figure it out how to do this. It
>is really hard for me to do this. How about you guys?
>Can you give me some idea about this.
If you have some background with linear analysis it's pretty much a 
matter of doing the problem as linear first, so you get an understanding 
of the response of the system, then you start adding non-linearities 
gradually, so you'll have a feel for what does what. 

If you don't have any background with linear work, get some first. 
Non-linear time history analysis can be a huge pain in the butt--lots of 
time steps and convergence criteria to deal with. The critical time step 
is usually not obvious, so it involves a fair amount of piecing through 
sets of results to find out the significant results. There's usually 
several 'artificial' inputs that may need tweaking, such as integration 
time steps, gap stiffnesses or tangent moduli. Program defaults are 
usually a good copmpromise, but not always, and you may find yourself 
doing a lot of fiddling around to get convergent results. Take it easy, 
and use a step-by-step approach.

Christopher Wright P.E.    |"They couldn't hit an elephant at
chrisw(--nospam--at)        | this distance"   (last words of Gen.
___________________________| John Sedgwick, Spotsylvania 1864)

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