General

General

Why does the presence of NLAD object help with convergence even when the re-meshing doesn’t occur?

    • FAQFAQ
      Participant

      NLAD resolves the convergence issue without any remesh because the code automatically removes “ETCON,set” from the ds.dat file when NLAD is activated. You can read more about this command here: https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v192/ans_cmd/Hlp_C_ETCONTROL.html This basically turns off enhanced strain formulation. This is the same as setting Element Control to “Manual” under Geometry branch in WB-Mechanical. Because of this, in some cases, one might observe convergence with the B-Bar formulation(KEYO,,1,0), but not with the default enhanced strain (KEYO,,1,2) formulation. It has nothing to do with NLAD actually. Please note that, even when there is an addition of a command snippet such as ‘keyo,1,1,0’ (which changes the element formulation for plane 182 element) located under the geometry branch it would still not resolve the issue. The reason is that as long as ‘ETCON,set’ has been executed, it will override any previously set KEYOPT settings. So the prescribed command object is being ignored. This explanation is actually found in the ETCONTROL command manual for ‘ETCONTROL’: “The program informs you of the best settings and resets any applicable KEYOPT settings automatically. This action overrides any previous manual settings.” Keywords: NLAD, Element Formulation, Remeshing