Hi everybody
I have a two degree of freedom system with nonzero initial displacements and velocities different at the two degrees of freedom. How I can analyze the free vibration of the system by OpenSees? Many thanks for your kind attention.
Best Wishes,
Precisely defined nonzero initial conditions for time integr
Moderators: silvia, selimgunay, Moderators
Re: Precisely defined nonzero initial conditions for time in
the problem is the initial velocities. if just displacements you could impose them, analyze using a static analysis and then remove them as is typically done.
in your case try a MultiSupport load patterns in which case you can set the velocity and displacement at the nodes using ground motions. just be sure to use Penalty method to enforce the constraints as you will have 0 dog if you try Transient. apply in 1 step and the remove. AT end of apply step just look at nodes to ensure you have displayed and gel wanted. Also if you specify the dish and velocities through a path file, watch to make sure the file has a zero at the start as this corresponds to tie 0 and when you do an analysis at time dT in the first line will be ignored.
in your case try a MultiSupport load patterns in which case you can set the velocity and displacement at the nodes using ground motions. just be sure to use Penalty method to enforce the constraints as you will have 0 dog if you try Transient. apply in 1 step and the remove. AT end of apply step just look at nodes to ensure you have displayed and gel wanted. Also if you specify the dish and velocities through a path file, watch to make sure the file has a zero at the start as this corresponds to tie 0 and when you do an analysis at time dT in the first line will be ignored.