Assign Acceleration to Node

[alannakate]

Hi, I would like to assign a sine function acceleration to a specific node in my structure instead of the ground acceleration that is the default for time history analysis. How can I do this?

Thanks!

 

[johnbridge231]

As far as I know you cannot do that in ETABS...

Analysis and Design of arbitrary cross sections
Reinforcement design to all major codes
Moment Curvature analysis

http://www.engissol.com/cross-section-analysis-design.html

 

[johnbridge231]

in SAP, sorry.

Analysis and Design of arbitrary cross sections
Reinforcement design to all major codes
Moment Curvature analysis

http://www.engissol.com/cross-section-analysis-design.html

 

[stressed]

This is easily accomplished in SAP2000 or ETABS if you can analyze the acceleration joint load as a sinusoidal time history force or imposed displacement (must have a support/restraint in order to use joint imposed displacement). Define sine/cosine function(s) in SAP2000. If you're modeling unbalanced equipment loads, for example, you will probably need to define both sine and cosine TH functions based on machine speed. Select the joint where you want to assign max sinusoidal load or imposed displacement using Assign>Joint loads, and assign that max load as a static load under a separate Load pattern. Then Define a time history load case (typically use modal type Time history) where you specify the load pattern which you used to assign max sinusoidal load, and associate it with the sinusoidal time history function that you've defined. For equipment vibration, you would include both the Sine function and Cosine function in the same time history case. Time steps X output need to match the total time of your TH functions based number of cycles and period

 

[johnbridge231]

if not?


Regards

Analysis and Design of arbitrary cross sections
Reinforcement design to all major codes
Moment Curvature analysis

http://www.engissol.com/cross-section-analysis-design.html

 

[alannakate]

Thanks, I've got it figured out.

 

[johnbridge231]

Ok, you are welcome.

Analysis and Design of arbitrary cross sections
Reinforcement design to all major codes
Moment Curvature analysis

http://www.engissol.com/cross-section-analysis-design.html

 

[stressed]

alannakate, I'm curious.. how did you solve the issue?