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eigen command should work fine without any analysis definition (provided that mass & stiffness is defined properly). In fact, it defines its own analysis, solver, algorithm etc.

See eigenAnalysis function in commands.cpp...

You have to define mass. See the manual for the command...

try
As the name suggests, you'll get plastic rotation, not the total rotation of the hinges...

Rodgers wrote:One more feature is to have OpenSees to save commands history into a file.

I believe this is possible with the following undocumented command: Hope this helps...

I would go with

http://www.amazon.com/exec/obidos/ASIN/ ... 53-9953721

What if the material assigned to the zeroLength element does not have eta as an input (e.g. steel01)?

i-node and j-node are the nodes you want to calculate the drift between. The recorder will 1. get the displacement of node i in direction of $dof1 , d1 2. get the displacement of node j in direction of $dof1 , d2 3. find the difference, diff = d1-d2 4. calculate the distance between the two nodes in...

Try reducing the time step by a factor (say 10) when a step does not converge. You can go back to your original time step after that. It is similar to what you have for switching between regular and modified Newton algorithms in the input file you posted... PS. If g stands for the PGA of your ground...

Try Steel01 with no hardening...

fmk wrote:i have fixed the code for these .. as i don't yet have permission to check them into cvs you will have to wait till the next release v1.6.0 due any day now.

If Frank does not have permission to check code into CVS, who has ???

Set the other hinge length to be zero ...

I'm looking at the source code and it reads

Changing BWH input to actual hinge length

for the latest change...

Try removing -time ...

Looking at the source code for Elastic unixaial material,
I guess it is the damping constant of a dashpot acting simulatenously with the elastic material ...

Well, I pulled it out from the source of v1.6.2. The CVS says it has last updated 2 years ago, so proceed with caution ...