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Hello, Is there a straightforward way to calculate the energy dissipated through Rayleigh damping in OpenSees? The methods I can think of would require the stiffness matrix to be output at every timestep of the analysis if damping proportional to tangent stiffness is used. This ends up being too res...

I have changed the model to a SDOF and no problems occur. The IDR file is created for each run. However, the IDR records do not record at t=0 when the record command is issues while all other recorders do. I noticed that for the original/full model (in addition to some of the IDR files not being cre...

Thanks for the reply. I will test this out and post the script/results.

I am running many time history analyses in OpenSees using a loop to change the ground motions. I am finding that some of the recorders will be skipped and not record. This is always a random THA in my suite. For example I will run 50 THA, and for number 20 my interstorey drift recorder will not have...

Thanks, I did try that example.

I think I may now understand the problem. I believe that the viscousdamper material model does not actually introduce a stiffness into the OpenSees model. Rather, it only outputs forces considering K and C values.

Hello, I am trying to model a SDOF system with a Maxwell model material in order to reproduce the results from (http://opensees.berkeley.edu/wiki/index.php/ViscousDamper_Material). I am trying to run a displacement time history analysis. The script would produce an error message "could not inve...

Great, thanks for the help.

Yes the dT option prevents the "record" command from recording at t=0, but only for the drift recorder. For other recorders there is no problem and all recorders save the state. Ex: These record a value at time = 0 twice, then t=0.01, t=0.02, ... recorder Node -file Vel.txt -dT 0.00999 -ti...

Hello, I am using several recorders during a time history analysis of a multistorey structure. I have found that the "recorder Drift" recorder does not obey the "record" command if a time step is specified for the recorder. I believe that there is a bug with the record command or...

Thanks for the help, roundoff was the problem.

Hi,
I am not using variable time steps for my input motion or variable transient analysis so that is not contributing to the problem.

thanks but I have the dash before dT so that is not cause of the problem (typed it in the forum post wrong).

I am having a problem with the node recorder. I am recording displacement at a node in one DOF. I specified the recorder time step to be 0.01. This works until t=1 sec, where the recorder time step randomly changes to 0.011. What would cause this to happen? The time history analysis I am conducting ...

Thank you Dr. McKenna, I have put a flag on my tests but the solution is flip-flopping between 2 states rather than converging. I decreased the time step to 0.001 and decreased the tolerance from 1e-8 as in most examples to 1e-3. Unfortunately it is not converging. (1) How can I determine an appropr...

Has this been solved? I am getting the same warning only when I used algorithm NewtonLineSearch