Author: marleigh Date: 2020-06-08 09:21:51 -0700 (Mon, 08 Jun 2020) New Revision: 12709 Modified: trunk/Vol_I_Keyword/CONTROL_ADAPTIVE.docx trunk/Vol_I_Keyword/CONTROL_REFINE_SHELL.docx trunk/Vol_I_Keyword/DEFINE_BOX_ADAPTIVE.docx trunk/Vol_I_Keyword/DEFINE_BOX_NODES_ADAPTIVE.docx trunk/Vol_I_Keyword/DEFINE_CURVE_BOX_ADAPTIVITY.docx trunk/Vol_I_Keyword/INTRODUCTION.docx trunk/Vol_I_Keyword/SECTION_SOLID.docx Log: renamed ADPOPT to ADPTYP for *CONTROL_ADAPTIVE. CONTROL_ADAPTIVE requires setting the ADPOPT field on *PART so the names were becoming confusing. ___________________________________________________ *PART's variable ADPOPT is described as follows ... ADPOPT Indicate if this part is adapted or not. (See also *CONTROL_- ADAPTIVE): LT.0: r-adaptive remeshing for 2D solids, |ADOPT| gives the load curve ID that defines the element size as a function of time. EQ.0: Adaptive remeshing is inactive for this part ID. EQ.1: h-adaptive for 3D shells. EQ.2: r-adaptive remeshing for 2D solids, 3D tetrahedrons and 3D EFG. EQ.3: Axisymmetric r-adaptive remeshing for 3D solid (see Remark 6) EQ.9: Passive h-adaptive for 3D shells. The elements in this part will not be split unless their neighboring elements in other parts need to be split more than one level. I think much of the confusion comes from people's individual perceptions of the terms "2D shell", "3D shell", and "2D solid". There is some ambiguity in those terms unfortunately and maybe those terms need to be better defined or replaced with clearer language. Here's the overall message. H-adaptivity splits elements. The "parent" element gets split into smaller "child" elements. H-adaptivity has long been applicable to shell elements, and is typically used in sheet metal forming simulations. This falls into the category of ADPOPT=1 above. It does not apply to plane strain or axisymmetric continuum elements, a.k.a. shell formulations 13,14,15, a.k.a. "2D solids"). More recently, h-adaptivity was extended to composite sandwiches comprised of a shell-solid-shell stackup. (Think of the shells as slices of bread and the solid as the meat inside the sandwich.) This is where the variable IFSAND comes into play. We should extend the description of ADPOPT=1 above to include "... and shell/solid/shell composite sandwiches." R-adaptivity completely remeshes the part. The code retains the outer surface of the part and fill it in with a completely new mesh. R-adaptivity (ADPOPT=2) can be applied to shell types 13,14,15, a.k.a. 2D solids, and to 3D solids. Axisymmetry (orbital) r-adaptivity (ADPOPT=3) is a very specialized type of r-adaptivity for axisymmetric geometries which are modeled in 3D with 3D solids. Jim 5/9/20 __________________________________________________________ So-called "tube adaptivity" performs shell h-adaptivity fission and fusion inside a tube (actually a torus). Invoked using *DEFINE_BOX_NODES_ADAPTIVE. _________________________________________________________________________ Except for the very special case of sandwich composites where a solid core is sandwiched between 2 shell layers (see IFSAND in *CONTROL_ADAPTIVE), adaptivity cannot be applied simultaneously to shells and solids because the two forms of adaptivity (h-adaptivity and r-adaptivity) used are entirely different and not compatible in the same model. ADPOPT=7 in *CONTROL_ADAPTIVE applies r-adaptivity to solid parts and should be used in combination with *CONTROL_REMESHING. For the solid parts you wish to adapt using this method of r-adaptivity, set ADPOPT in *PART (which is an entirely different thing than ADPOPT in *CONTROL_ADAPTIVE) to 2. When using this type of adaptivity, an adapted solid part should not share nodes with any other part. An example of this type of adaptivity is provided here ... http://ftp.lstc.com/anonymous/outgoing/support/EXAMPLES/extrude_3d_radapt.finer.k.gz . ADPOPT=1 or 2 in *CONTROL_ADAPTIVE applies h-adaptivity to shell parts. For the shell parts you wish to adapt using this method of h-adaptivity, set ADPOPT in *PART to 1. An example of this type of adaptivity is provided here ... http://ftp.lstc.com/anonymous/outgoing/support/EXAMPLES/sphere_hadapt_noerode.k . jd Ticket#2018032310000104 ________________________________________________ There are other ADPOPT options in *CONTROL_ADAPTIVE, e.g., 2D r-adaptivity, orbital adaptivity, not discussed above. Also, see *CONTROL_REFINE_option for yet another types of adaptivity.