UniformExcitation output analysis

Hello! In this section we'll talk about the post processing module and the data visualization.
Post Reply
whzju
Posts: 8
Joined: Mon Oct 28, 2019 10:25 am

UniformExcitation output analysis

Post by whzju » Mon Dec 23, 2019 3:00 pm

Hi everyone,

I am performing some transient analysis on a pile foundation recently.
I use the "UniformExcitation" to apply the acceleration by fixing the bottom boundary.
But, I am confused about the output. The opensees said when using "UniformExcitation", the results are relative value.
What does this represent?
If anyone is familiar with this, could you please explain to me.

Many thanks,
Huan

STKO Team
Posts: 287
Joined: Tue Oct 29, 2019 8:45 am

Re: UniformExcitation output analysis

Post by STKO Team » Mon Dec 23, 2019 3:16 pm

When you use UniformExcitation, if you plot the displacement of a node, that would be the relative displacement, i.e. the displacement relative to the ground displacement. That is, you will see your model move, but with the base fixed.
If instead you use MultiSupporExcitation, then the output will be absolute, i.e. the ground motion is included in the output.

whzju
Posts: 8
Joined: Mon Oct 28, 2019 10:25 am

Re: UniformExcitation output analysis

Post by whzju » Tue Dec 24, 2019 3:15 am

Thanks for the reply.
Is this also the same for the acceleration?
So the output is the relative acceleration for a fixed ground bottom and if we want the actual acceleration at the ground surface we need to add the input acceleration at the ground bottom?

Post Reply