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Pritam K

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  1. Pritam K

    Error in FAIL_JOHNSON

    Hi George, Just for Information, the value of a, b & n is automatically generated by RADIOSS when we used LAW 2 with Iflag=1. In some other discussion you attached a file (named: b&n_Law2.xlsx) to calculate a, b & n. But when I am using that file to calculate the values it is not matching with the value auto calculated by RADIOSS. This is the out file generatid with a, b & n:
  2. Pritam K

    Error in FAIL_JOHNSON

    Thanks George, Do we need to input Sig_max also? Is Eps_max and Sig_max is the value of strain & stress respectively where material ruptures? (I mean the last point of stress strain curve)
  3. Pritam K

    Error in FAIL_JOHNSON

    Thanks George, In my simulation I am using normal steel of standard grade. Can you please guide me what should be the inputs (may be in limit) for LAW2 parameters (a, b, n..) and failure parameters. It will be a great help for my reference. Thanking You.
  4. Pritam K

    Error in FAIL_JOHNSON

    Hi George, Thanks for your prompt reply. But still the crack doesn't look realistic and still material deletion is there. How to estimate the Parameters in failure criteria. As you said: I am clueless about this and how to rectify this. I just taken random valued to set the methodology. If possible modify the values as per recommendation and set the methodology. meanwhile I will go through the video tutorial. thanking You.
  5. Pritam K

    RADIOSS Johnson cook material

    Hi, As I observed in some example of steel with Iflag=0, the parameter b is seems to be the ultimate strength. Is it the ultimate strength or some other value. And as per your excel attached @George P Johnson "n" value seems to be very high attaching file below.
  6. Pritam K

    Error in FAIL_JOHNSON

    Hi I am trying to simulate ship collision with Failure criteria. For that I tried with simple plate impact simulation. I used Johnson Failure prop. Difficult to input the value D1, D2, D3.... Anyhow managed to input it from example given. But don't know the significance of these inputs. Than the ERR shows very high as attached image below. The animation also shows some unusual behavior. I tried with Ixfem=1 (as i want to see the proper cracks formation), but it shows error, so goes with Ixfem=0. Attaching the deck also. Please check any error it it and suggest your valuable comments and any modification needed. Thanking You. Bow impact.zip
  7. Pritam K

    Collision Detection

    Hi George, I have seen your mail. As I noticed you have not given any thickness, as there is no thickness assigned to any components till now. If uniform thickness(say 10mm) assigned then there are penetrations. Can we ignore the thickness penetration between 2 components?? And regarding the contact, there is a fixed connection between all three components. I don't think TYPE 11 will provide a fixed contact as TYPE2 Thanking You.
  8. Pritam K

    Collision Detection

    Hi George, Sorry to say that I have not received the mail. Please resend or use this mail id: pritam.patel11@gmail.com Thanking You.
  9. Pritam K

    Collision Detection

    HI George, Shared the file.
  10. Pritam K

    Collision Detection

    Hi, There is no interfaces present now in the model
  11. Pritam K

    Collision Detection

    Thanks George, So, is it important to consider the thickness overlapping also? But in my second query, in a single component also its showing penetration, as there is no other component to thickness overlap.
  12. Pritam K

    Collision Detection

    Hi, I used collision detection tool to find the intersection and penetration on the model. In my model there is a gap of 5mm between two components, but in collision detection tool its showing as a penetration as indicated by vectors.(as in below image) Secondly, within the same component its showing as penetration as indicated by vector arrows. (Image attached below) But when checking with the simple intersection tool (Analysis>safety>intersection) these are not shown. How to resolve these. Thanking You.
  13. Hi A J Prins I have gone through your problem setup. I am doing a similar kind of problem of Ship to Ship collision using Radioss. (Struck ship is freely floating on water modeled with SPH elements and striking vessel collides with some INVEL.) Regarding your issue of pre-stressed hull before collision due to buoyancy and self load which i quoted above, you can model water with SPH elements. Hope this approach of modeling the problem will capture proper dynamics of the problem without any assumption. Thanking You.
  14. Hi, I have worked in FOAM Material using LAW 70 in one of my project. I tried validating LAW 70 for different scenarios. Attaching some sample validation case for reference. Hope it may help you. Thanks. Comp_20mm_0000.rad penetration_1DOF_0000.rad E_1100_0000.rad
  15. Pritam K

    SPH Setup Error

    Thanks George, I have gone through the example and taken some inputs from that. But now concern about the two different pitch in a same component SPH element. Can you please advice and help me regarding my concern. Thanking You.