Applying ramped displacement load in static analysis

  • 2.2K Views
  • Last Post 26 July 2018
  • Topic Is Solved
Sepi posted this 25 July 2018

Hello everyone,

 

So I am doing a static(quasi-static) analysis and I want to apply the load in my model on a set of nodes in form of displacements that gradually increase with each load step, like a ramp. It means I want to start from u_x=0 at these nodes and apply an additional amount of delta_u_x in each load step until I reach the ultimate value for it. 

 

Like: Start: u_x=0

        Go up in a ramp of 10 load steps, in each increment add 1 unit to u_x

       Finish u_x=10 

 

Please could you let me know how I should do this.

 

Thanks a lot.

Sepideh

Order By: Standard | Newest | Votes
peteroznewman posted this 25 July 2018

Hello Sepi,

Apply a displacement of 10 mm to the face or edge that you want to move.

Under Analysis Settings

Under Step Controls, change Automatic Time Stepping to On

Initial Substeps 10

Minimum Substeps 10

Maximum Substeps 100

further down, turn on Large Deflection.

You should get exactly 10 substeps of 1 mm each unless the solver has difficulty converging, then you might get extra substeps.

Regards,

Peter

  • Liked by
  • Sepi
SandeepMedikonda posted this 25 July 2018

Hello,

Increase no. of steps in the analysis settings:

then add tabular data for your displacement:

(Edited)

~Sandeep

 

  • Liked by
  • peteroznewman
peteroznewman posted this 25 July 2018

Sepi,

There are two ways to accomplish what you want, Sandeep shows a method that will give you results at exactly the 1 mm increments, while the method I described might give you that, but could give you results off the 1 mm marks.

But in either case, turn on the Large Deflection setting.

Peter

  • Liked by
  • Sepi
Sepi posted this 26 July 2018

Hi Sandeep,

 

Thank you for your reply. I have to admit that I do not know how to create a table which assigns values for the displacement at specific load sub-steps.

 

What I am doing is that I have to implement my own models in an open source software, but I also want to set up a quick model in ANSYS to do a double check of the results of my own program with ANSYS. 

 

Thanks

Sepideh

Sepi posted this 26 July 2018

Hi Peter,

 

Thank you so much. It seems to be working. However, I still have an additional question: I want to plot the reaction forces vs displacement at the nodes where I am applying the displacement load. I have no clue how I can save these data for each substep in form of a table or array which I can later use for plotting. Do you have any suggestions for me?

 

Thanks.

Sepideh

SandeepMedikonda posted this 26 July 2018

Hi Sepideh,

  You might find this page from the manual helpful. 

  You can also calculate the force reaction as shown here:

and then scope it according to what you need:

For plotting force vs displacement, check out this post from earlier today.

Regards,

Sandeep

Close