Reset the displacements after gravity analysis

[luismir]

I would like to ask which is the best way to make the displacements at all nodes equal to zero, after the initial gravity analysis (for instance, for a soil model), while keeping the stresses and strains from the previous analysis.
So basically I just want to have all the nodes displacements zero, without affecting the rest.
I'm doing a dynamic analysis so it has to be without using the InitialStateAnalysisWrapper.

Thanks for your help on this matter.

[fmk]

you cannot do so. why would you want to?

[luismir]

Hi Frank,

I want to do it because just imagine that you need to have the initial stress field on the ground.
You don't want to have any displacements because at the present moment the ground is already in the position after the gravity displacements took place.
So you need to begin the analysis after gravity with the corresponding stress field but with no displacements.

Thanks

[fmk]

if you are concerned with the additional elements you add to the stressed model: most (not all) elements in OpenSees will assume when the user adds them that they are to be in an unstressed condition, as such they will note any current displacements at the end nodes when added and subtract these off when determining their deformation during the analysis