3D Design

3D Design

How to set the failure criteria for deformation in Six Sigma Analysis (SSA)

    • hquoc87
      Subscriber

      Hello everyone,


      I'm new to Ansys and I'm using Ansys Workbench to simulate the effect of traffic load to the buried pipe. I wanted to calculate the pipe's probability of failure under the effect of the traffic load. I used the deformation as the performance. Technically, the pipe is considered as failed when its deformation value exceeds 5% of the pipe diameter. However, I couldn't find anywhere to set the failure criteria based on the deformation parameter or either the range for deformation (so that in the CDF plot, it can show the probability of deformation value from 0 to the threshold of deformation which is 2.7in in my case). The only thing that I could see was the calculated value of deformation. Can anyone please help me with this? Any information helps.




      Thank you so much!


      Regards,


      Hung.

    • peteroznewman
      Subscriber

      If you Attach a .wbpz Archive file to your post, it makes it easier to investigate an answer to your question.

    • hquoc87
      Subscriber

      Hi Peter,


      I just attached a .wbpz file. Thank you for your help.


      Regards,


      Hung.

    • peteroznewman
      Subscriber

      Also say which Release of ANSYS you are using.

    • hquoc87
      Subscriber

      I'm using Ansys 2019R1


      Best,


      Hung.

    • peteroznewman
      Subscriber

      I looked at your model. You need to improve the mesh before you do a lot of work on this model. You have a thin layer on top called AC, and an even thinner set of blocks on top of that layer to apply loads to.



      Apply a Multizon mesh method and you can get Hex elements.



      But do you even need to thin blocks?  Why don't you just create faces on the AC layer and have no thin block on top?


      The subgrade around the pipe and the Base has a very coarse mesh. I would reduce the element size on that also.



      You want the elements on either side of the contact to have similar sizes. This pipe has a much finer mesh.


    • peteroznewman
      Subscriber

      Another problem with your Parametric model is when you change the diameter of the pipe, you don't also change the diameter of the hole in the Subgrade. 


      Since there is bonded contact between the pipe OD and the hole, maybe you can get away with this, but it is a mistake in your model that you should correct.

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