Ground acceleration

[Anonymous]

Hello, Could somebody please explain the process for applying a ground acceleration time history to a model in RSA. The acceleration data is available in an Excel or text file with a fixed time step.

Thanks

[Rafal.Gaweda]

See slide 10 ("Direction X , Direction Y") in webinar 13

http://forums.autodesk.com/t5/robot-structural-analysis-forum/robot-structural-analysis-webinars/td-...

[Anonymous]

Thanks for the response - I'll take a look at the webinar.

[Anonymous · Accepted solution]

Thankyou for the response - I'll take a look at the webinar.

[Anonymous]

Thanks for your response Rafal. I have now run this analysis and have a further question if I may. My understanding is that the accelerations output from an imposed base acceleration analysis are absolute values (I think that was an answer to another post), but could you advise what the basis is for the displacements and velocities.

Many thanks

[Rafal.Gaweda]

What do you mean by that?

[Anonymous]

Rafal,

What I was trying to find out was whether the displacements/velocities/accelerations output from the time history analysis are absolute values or values relative to ground.

Thankyou

[Pawel.Pulak · Accepted solution]

Hi Ryan,

in Robot it depends whether THA is run for Direction X, Direction Y, Direction Z  load cases or for standard load cases:

1. For Direction X, Direction Y, Direction Z  load cases displacements/velocities/accelerations output from the time history analysis are values relative to ground
2. For standard load cases (including standard load cases with imposed support displacements, velocities or accelerations) displacements/velocities/accelerations output from the time history analysis are absolute values

More information related to it can be found in this Robot discussion forum post.

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