General Mechanical

General Mechanical

Multiple load step solution

    • ashish35
      Subscriber

      Hello,


      After importing the stress tensors from residual stress solution of ANSYS additive, I need to allow the body to deform in one load step and then add another load step with different boundary and loading condition in a new analysis. How can I define a step for imported initial stress and add another step with different BC? Any help would be appreciated.


      Best,


      Ashish

    • Sandeep Medikonda
      Ansys Employee

      Ashish, moving this to the correct thread so that it will get more traction.

    • Sandeep Medikonda
      Ansys Employee

      Ashish,


      If you can stay within Static Structural, you can use "User Steps" available under the AM Process Sequence and simply add steps to their analysis without moving in and out of Mechanical. Additional info on AM User Step.


      Regards,


      Sandeep


       


       

    • ashish35
      Subscriber

       Hi Sandeep,


      This is all the steps I can add in the Static Structural step:


      1) Build Step


      2) Cooldown Step


      3) Basse Removal Step


      4) Support Removal Step.



      Regardless of this, since AM module uses voxel meshing system, my professor is skeptic about using the same mesh to predict stresses due to external load because we do not usually see stress convergence with that mesh.


      So I have mapped out the stresses generated by AM module to a new mesh (which can represent the correct geometry) using "External Data" tool to a new static structural analysis. My concerns are:


      1) the mapped out stresses should produce the correct deformation (which I have checked and it got the approximate value and it's fine for me)


      2) Now, I need to add boundary condition and an external load to the deformed geometry.


      My question is, if I just add new BC, external load and imported initial stress all at once, how does ANSYS take this?


      If it is incorrect to do that, how do I use imported initial stress in one time step and apply new BC and external loads in another?


       


      Best,


      Ashish

    • Sandeep Medikonda
      Ansys Employee

      Ahh yes, This is new in 19.2.


      I remember your question on correct deformation from your last post.


      I don't think it is a problem since you are applying BC to the part you have already built. It's just like any other structural analysis with the exception that you are starting with a residual stress in your part.


      An easy way to apply initial stress to nodes would be to select the elements for given material id and then selecting the nodes associated with the selected elements and then using inistate for nodes.


      Also please note that to get the same stress state and reactions, you need to read in elastic strain, plastic strain, equivalent plastic strain and plastic work, but do not read in the stress. 


      If you do read in the stress, then you should not read in the elastic strain, but you still need to read in the plastic strain components listed above, because the plasticity is not fully represented otherwise.


      Regards,


      Sandeep


      Best Practices to posting on the community

    • ashish35
      Subscriber

      Sandeep,


      Yes, we are yet to get the 19.2 version. Does this version also have newly added AM materials?


      Could you please explain me how do I use the INSTATE command? Is it different from transferring tensors from "External data"?


      Best,


      Ashish

    • Sandeep Medikonda
      Ansys Employee

      Hi Ashish,


      Just these 4 materials so far.



      I thought there was a post in our previous discussion where you were able to do this. Can you please check out these manual resources on the INSTATE command?


      Resource 1


      Resource 2


      Resource 3


      Regards,


      Sandeep


       

    • ashish35
      Subscriber

       Hi Sandeep,


      Could you please provide me equations that I could feed into user defined result for plastic strain components and plastic work?


      Best,


      Ashish

    • Sandeep Medikonda
      Ansys Employee

      Hi Ashish,


        First of all, I am not sure what equations you are referring to? but any or all equations that I am allowed to provide will be from the manual.


        Also, please note that user-defined subroutines are not a supported feature (typically of any commercial product that I can think of, not just ANSYS).


      Regards,
      Sandeep

    • Ashish Khemka
      Ansys Employee

      Hi Ashish,


      I think that you are referring to User defined expressions for Plastic Strain Components and Plastic Work. Please refer to the Worksheet tab after clicking on the Solution, which will list all the available expressions.


       


      Regards,


      Ashish Khemka

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