General Mechanical

General Mechanical

Applying ramped displacement load in static analysis

    • Sepi
      Subscriber

      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

    • peteroznewman
      Subscriber

      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

    • Sandeep Medikonda
      Ansys Employee

      Hello,


      Increase no. of steps in the analysis settings:



      then add tabular data for your displacement:



      (Edited)


      ~Sandeep


       

    • peteroznewman
      Subscriber

      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

    • Sepi
      Subscriber

      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
      Subscriber

      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

    • Sandeep Medikonda
      Ansys Employee

      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

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