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LS-DYNA implicit stiffness matrix and output

    • Fady Elshazly


      Is there any way to control the stiffness matrix formulation in LS-DYNA implicit. I mean to form it at the beginning of the solution and not to change it.

      Is there any way to save only the results (displacement, velocity and acceleration) of specific nodes in an ASCII/text file directly without the need to open lsprepost again?


    • Ram Gopisetti
      Ansys Employee


      elobrate your first point ( what method you are look for, etc) 

      try using the database_history_node (id, set)

      in smp run it outputs nodeout which has following header with time stamp 

       nodal point  x-disp     y-disp      z-disp      x-vel       y-vel       z-vel      x-accl      y-accl      z-accl      x-coor      y-coor      z-coor

      in mpp run it will be output in binout you can also check the elout database 

      cheers, ram 

      • Fady Elshazly

        I am using mpp and history node id. I need to save the recorded nodes in history node id in a file that can be red directly without the need to open lsprepost again. I mean to import it in matlab or something and read it as a txt or other readable extensions.

    • Jim Day
      Ansys Employee
      To retain the same stiffness matrix for each step in a LINEAR implicit analysis, set NSOLVR= -1 (negative one) in *CONTROL_IMPLICIT_SOLUTION.
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