About dynamic analysis

[benliangxiao]

Hi,

After using "analyze 1 $dt" to do one step dynamic analysis, I'd like to know if there is anyway to remove the results of the this step and restart from the previous step.

Many thanks,
Xiao.

[vesna]

If you want to move your model to the state where it was before that one step of analysis you can do it by using "reset" command: http://opensees.berkeley.edu/wiki/index ... et_Command

[benliangxiao]

vesna wrote:
> If you want to move your model to the state where it was before that one
> step of analysis you can do it by using "reset" command:
> http://opensees.berkeley.edu/wiki/index ... et_Command


Thanks!
If, say I have done the 2000 steps of dynamic analysis, after finishing the step 2001,
does this command could make the model go back to step 2000, that means discard the results of step 2001?

Xiao.

[vesna]

No, this command would set the state of the domain to its original state.

[benliangxiao]

vesna wrote:
> No, this command would set the state of the domain to its original state.

Thanks!
So is there anyway can do the things I mentioned?

Xiao.

[vesna]

you can use database commands (http://opensees.berkeley.edu/wiki/index ... e_Commands) to save and restore model states.

[benliangxiao]

vesna wrote:
> you can use database commands
> (http://opensees.berkeley.edu/wiki/index ... e_Commands) to save and
> restore model states.

Thank you!
But when I used them, it always came out an error message "invalid command name "save"".
I'm using the latest version of OpenSees.

Xiao.

[fmk]

you need to issue the database command before the save command, the save and restore do not exist until after the database command is called.

be warned the database command does not work for all ele and materials.

[nitadorakis]

Hi,

Regarding the DATABASE command, I noticed that it doesn't seem not to work with TripleFrictionPendulum elements.
Is there any alternative way to restore a model in the state just after static analysis when doing IDA and want to exclude the static analysis part from the IDA loop?
When using the RESET command within the IDA loop, not only the dynamic but also the static analysis response results are deleted (even though the static analysis part is outside the loop).

[vesna]

Database command is the only way to restore model states.

Which TripleFrictionPendelum element do you want to use? If it is this one: http://opensees.berkeley.edu/wiki/index ... n_Pendulum we can ask the developer to modify the code to allow for database command.

[nitadorakis]

Thanks for your reply.
Indeed, I use that element, and I would be gratefull if this modification-addition could be done.

[vesna]

We will send a request.

[nitadorakis]

Thanks.
This will save a lot of computational time.