LS Dyna

LS Dyna

Hourglass (maybe?) Problem

    • francescocurzio
      Subscriber
    • Andreas Koutras
      Ansys Employee

      Hourglassing occurs when the hourglass stiffness, and thereby the hourglass energy, is low. Maybe try with a bit larger hourglass coefficient. Also note that ERODING_SURFACE_TO_SURFACE contact is an "old" , non-automatic, contact. You can try replacing it with AUTOMATIC_SURFACE_TO_SUFACE and see if it has any effect. Alternatively, you can just use ERODING_SINGLE_SURFACE (for everywhere), which is an automatic contact. SNLOG has a different meaning for SOFT=2, see the manual.
    • francescocurzio
      Subscriber
      **** sir, thank you for tour reply! I don't understand quote well you statement about hourglass; It should be that when hourglass energy is low i wont have hourglass modes of deformation! In fact, when i use fully integrated solid formulation (e.g. ELFORM=-1) there cant be hourglass modes, and so i get 0 hourglass energy.
      Thank you for tour suggestion about eroding contact, i didnt know it is non-automatic contact! I have Aldo checked for SNLOG option it doesnt do anything when SOFT=2 is active (It Will only print a message in d3hsp file)!
      Now im trying to use interior contact because i have also thinked that the strange modes of the deformation in the picture are linked to the large displacement of the nodes of foam materiale elements
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