Dear All,
is it possible to run a DisplacementControl static analysis applying displacement increments to more than one degree-of-freedom?
I did not find any tcl example to do this.
Many thanks!!
Giuseppe
multi-DoFs DisplacementControl analysis
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giuseppe.abbiati
- Posts: 11
- Joined: Mon Jan 24, 2011 7:09 am
- Location: Università di Trento
Re: multi-DoFs DisplacementControl analysis
it is not displacement control but imposed displacements you want. displacement control tries to determine the change in the load factor needed to give you the change in displacement at a particular dof at a node. there is no way to control the change in multiple dof as there is no 1 load factor that will give you this result (unless it is a linear system and the ratio requested is what you are going to get with displacement control in the first place). imposed displacements is where you set the displacements at the boundaries and let the structure react to them as it would.
use MultipleSupport excitation to impose displacements. you define multiple ground motions in the pattern (1 for each node you want to control if they all move differently) and then impose that motion at a dof at a node. you need to look at these:
http://opensees.berkeley.edu/wiki/index ... on_Pattern
http://opensees.berkeley.edu/wiki/index ... on_Command
http://opensees.berkeley.edu/wiki/index ... on_Command
as for the use of multi-support in a static analysis. use loadcontrol where the delta lambda you provide is like the delta t in the transient analysis. both change the pseudo time i nthe domain by the delta and it is that time that the load pattern will provide to the time series or ground motion to get the appropriate load factor for that time. this is then used to determine the mag of load or displacement applied to the model.
use MultipleSupport excitation to impose displacements. you define multiple ground motions in the pattern (1 for each node you want to control if they all move differently) and then impose that motion at a dof at a node. you need to look at these:
http://opensees.berkeley.edu/wiki/index ... on_Pattern
http://opensees.berkeley.edu/wiki/index ... on_Command
http://opensees.berkeley.edu/wiki/index ... on_Command
as for the use of multi-support in a static analysis. use loadcontrol where the delta lambda you provide is like the delta t in the transient analysis. both change the pseudo time i nthe domain by the delta and it is that time that the load pattern will provide to the time series or ground motion to get the appropriate load factor for that time. this is then used to determine the mag of load or displacement applied to the model.