General Mechanical

General Mechanical

Thick Wall Residual Stress Determination

    • andrew2121
      Subscriber

      Hi,


      I am trying to determine the residual stress on a 2D axisymmetric thick wall model. The model is a quarter cross-section of a barrel. Frictionless supports were defined on the straight edges of the model. I have set the material to Structural Steel NL and turned Large Deflection on. Structural Steel NL appears to yield at 2.5E8 Pa per the engineering data so I created a 2 step pressure load. 0 Pa to 1e10 Pa and then back to 0 Pa.


      Now I would like to run the simulation to determine the residual stresses and a true stress-strain curve. From the error messages it appears that it is unable to converge to a solution. I have played around with the mesh sizing, but that did not help either.


      Any guidance would be greatly appreciated.


      Thank you.


       

    • peteroznewman
      Subscriber

      Hi Andrew,


      You can plot the residual stress with such a model, but don't try to plot a stress-strain curve, that is already defined as an input in the Structural Steel NL material definition.


      Here is a list of 110 results from a Google search on "unable to converge" on this site. The first thing to try is to turn Auto Time Stepping On and set the Initial, Minimum and Maximum Substeps to 100.


      Regards,
      Peter

    • andrew2121
      Subscriber

      Thank you Peter.


      I was able to resolve the issue by reducing the applied pressure and turning on Auto Time Stepping as you suggested.


      As a follow up, can you confirm that the residual stress after unloading is indicated by the red arrow in the figure?

    • peteroznewman
      Subscriber

      Use the Insert Image button in your reply. You can't copy and paste from Word into the discussion and have an image make it into the post.

    • andrew2121
      Subscriber

      I have used the Insert Image command here. Thank you.


       


    • peteroznewman
      Subscriber

      Looks good.

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