<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><blockquote type="cite" class=""><div dir="ltr" class=""><div class="gmail_quote"><div class="">Isn't the whole point of cohesive elements that they are not everywhere? All the papers they are citing in the one you link use them only along</div><div class="">the crack path.</div></div></div></blockquote><div class=""><br class=""></div><div class=""> don’t have any reliable way of determining the origin of the crack path and hence can’t selectively put them in places. The mesh will be subjected not only to physical external loads but internal stresses due to heat-flux and other fluid flow. Not that it can be entirely avoid, but selectively putting in the cohesive elements makes the crack mesh-dependent which would be minimized if the elements are everywhere.</div><div class=""><br class=""></div><blockquote type="cite" class=""><div dir="ltr" class=""><div class="gmail_quote"><div class="">you should probably just try to reformulate as a hybridized DG method, since that is what you would have essentially.</div></div></div></blockquote><div class=""><br class=""></div>If I was writing my own solver, sure, but there is a lot of infrastructure available through warp that rewriting it all in my own impls is unpalatable…<br class=""><div class=""><br class=""><div class="">
<div dir="auto" style="caret-color: rgb(0, 0, 0); color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div>Best regards,<br class=""><br class="">Jacob Faibussowitsch<br class="">(Jacob Fai - booss - oh - vitch)<br class="">Cell: (312) 694-3391</div></div>
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<div><br class=""><blockquote type="cite" class=""><div class="">On Sep 2, 2020, at 14:35, Matthew Knepley <<a href="mailto:knepley@gmail.com" class="">knepley@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><div dir="ltr" class="">On Wed, Sep 2, 2020 at 2:26 PM Jacob Faibussowitsch <<a href="mailto:jacob.fai@gmail.com" class="">jacob.fai@gmail.com</a>> wrote:<br class=""></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div style="overflow-wrap: break-word;" class=""><div class=""><blockquote type="cite" class=""><div dir="ltr" class=""><div class="gmail_quote"><div class="">It is a complicated topological problem and I do not have a general solution. </div></div></div></blockquote><br class=""></div><div class="">Definitely. I’ve been writing my own impls in python this past month that follows the algorithm laid out here <a href="https://www.sciencedirect.com/science/article/pii/S2352711018300797" target="_blank" class="">https://www.sciencedirect.com/science/article/pii/S2352711018300797</a> but without a robust topology framework (one that I’m not interested in reinventing the wheel for in python) I have stalled.</div><br class=""><blockquote type="cite" class=""><div dir="ltr" class=""><div class="gmail_quote"><div class="">Maybe if you explain a little more about the problem you want to use it for, I can suggest some things to make it easier.</div></div></div></blockquote><div class=""><br class=""></div>I am using a different code (warp3D if the name is familiar) to do some fairly large-scale fracture mechanics simulations which is to be integrated into a stack of other simulations. warp3D offers 2 methods of crack propagation, element-extinction and cohesive zone model. Warp requires the mesh to have the cohesive elements pre-baked into it (AFAIK it cannot generate them on the fly). I am fairly locked into using warp3D as well as the cohesive element approach (element extinction is currently used but doesn’t play nice). <div class=""><br class=""></div><div class="">My goal is therefore to insert cohesive elements into an existing tet mesh. The meshes are arbitrary, massive, and geometrically complex and the loading configuration is equally unpredictable so it is unfeasible to try and predict intelligently where to insert the cohesive elements.</div></div></blockquote><div class=""><br class=""></div><div class="">This is the part I do not understand. Isn't the whole point of cohesive elements that they are not everywhere? All the papers they are citing in the one you link use them only along</div><div class="">the crack path. If you are going to crack every face in your mesh, you should probably just try to reformulate as a hybridized DG method, since that is what you would have essentially.</div><div class=""><br class=""></div><div class=""> Thanks,</div><div class=""><br class=""></div><div class=""> Matt</div><div class=""> </div><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div style="overflow-wrap: break-word;" class=""><div class="">Accuracy of the crack-front paths are of vital importance, so the only viable options are to either insert the elements everywhere, or in closely packed grains that permeate the whole mesh.</div><div class=""><br class=""></div><div class=""><div class=""><div class=""><div dir="auto" style="letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;" class=""><div class="">Best regards,<br class=""><br class="">Jacob Faibussowitsch<br class="">(Jacob Fai - booss - oh - vitch)<br class="">Cell: (312) 694-3391</div></div></div><div class=""><br class=""><blockquote type="cite" class=""><div class="">On Sep 2, 2020, at 14:08, Matthew Knepley <<a href="mailto:knepley@gmail.com" target="_blank" class="">knepley@gmail.com</a>> wrote:</div><br class=""><div class=""><div dir="ltr" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;" class=""><div dir="ltr" class="">On Wed, Sep 2, 2020 at 1:43 PM Jacob Faibussowitsch <<a href="mailto:jacob.fai@gmail.com" target="_blank" class="">jacob.fai@gmail.com</a>> wrote:<br class=""></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div class="">I’m getting an argument out of bounds error (attached) but I suspect it’s because I’m feeding in bad input to either calls (I am marking __all__ vertices in the mesh in my input label to DMPlexLabelCohesiveComplete). Are the cohesive grains allowed to intersect? Does a cohesive region have to be closed? Does it have to be entirely enclosed by the mesh, i.e. not touching any of the boundaries?</div></blockquote><div class=""><br class=""></div><div class="">I see. If you want every face in the mesh pulled apart, we will likely have to write another implementation. For the fault problem, it is essential to</div><div class="">figure out what side of the fault each cell is on. It is a complicated topological problem and I do not have a general solution. Thus you cannot have</div><div class="">crossing faults in my implementation. You can have one fault dead-end into another. It can touch a boundary. If it ends inside the mesh, you should</div><div class="">make a boundary label around the interior boundary so it can be clamped shut.</div><div class=""><br class=""></div><div class="">Maybe if you explain a little more about the problem you want to use it for, I can suggest some things to make it easier.</div><div class=""><br class=""></div><div class=""> <span class="Apple-converted-space"> </span>Thanks,</div><div class=""><br class=""></div><div class=""> Matt</div><div class=""> </div><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div class=""><div class=""><div dir="auto" style="letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;" class=""><div class="">Best regards,<br class=""><br class="">Jacob Faibussowitsch<br class="">(Jacob Fai - booss - oh - vitch)<br class="">Cell: (312) 694-3391</div></div></div><div class=""></div></div><div class=""><div class=""></div><div class=""><br class=""><blockquote type="cite" class=""><div class="">On Sep 2, 2020, at 09:28, Matthew Knepley <<a href="mailto:knepley@gmail.com" target="_blank" class="">knepley@gmail.com</a>> wrote:</div><br class=""><div class=""><div dir="ltr" class=""><div dir="ltr" class="">On Mon, Aug 31, 2020 at 5:39 PM Jacob Faibussowitsch <<a href="mailto:jacob.fai@gmail.com" target="_blank" class="">jacob.fai@gmail.com</a>> wrote:<br class=""></div><div class="gmail_quote"><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div class="">Hello All,<div class=""><br class=""></div><div class="">What is the simplest possible configuration required to insert cohesive cells into a plex? Plex/tests/ex5.c would be the example to ape here but there is a lot there that I don’t (think) I need like a DS or any kind of physics. For now, I am essentially looking to:</div><div class=""><br class=""></div><div class="">1. Read the mesh</div><div class="">2. Perform some mesh analysis</div><div class="">3. Slap some cohesive cells along one/multiple areas identified in the previous step <span class="">(maybe even everywhere?)</span></div><div class="">4. Save the new mesh</div><div class=""><br class=""></div><div class="">This doesn’t even have to parallel. </div></div></blockquote><div class=""><br class=""></div><div class="">You can try it out easily. If it does not give you what you want, we can fix that up.</div><div class=""><br class=""></div><div class=""><a href="https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/DMPLEX/DMPlexConstructCohesiveCells.html" target="_blank" class="">https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/DMPLEX/DMPlexConstructCohesiveCells.html</a> will give you back a mesh<br class=""></div><div class="">with the cohesive cells inserted. For input, you need a suitable label.</div><div class=""><br class=""></div><div class=""><a href="https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/DMPLEX/DMPlexLabelCohesiveComplete.html#DMPlexLabelCohesiveComplete" target="_blank" class="">https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/DMPLEX/DMPlexLabelCohesiveComplete.html#DMPlexLabelCohesiveComplete</a> starts<br class=""></div><div class="">with a label marking vertices on an internal surface and creates the label needed by the call above.</div><div class=""><br class=""></div><div class="">Let me know if that works.</div><div class=""><br class=""></div><div class=""> <span class=""> </span>Thanks,</div><div class=""><br class=""></div><div class=""> Matt</div><div class=""> </div><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div class=""><div class=""><div class=""><div dir="auto" style="letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; text-decoration: none;" class=""><div class="">Best regards,<br class=""><br class="">Jacob Faibussowitsch<br class="">(Jacob Fai - booss - oh - vitch)<br class="">Cell: (312) 694-3391</div></div></div><br class=""></div></div></blockquote></div><br clear="all" class=""><div class=""><br class=""></div>--<span class=""> </span><br class=""><div dir="ltr" class=""><div dir="ltr" class=""><div class=""><div dir="ltr" class=""><div class=""><div dir="ltr" class=""><div class="">What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br class="">-- Norbert Wiener</div><div class=""><br class=""></div><div class=""><a href="http://www.cse.buffalo.edu/~knepley/" target="_blank" class="">https://www.cse.buffalo.edu/~knepley/</a><br class=""></div></div></div></div></div></div></div></div></div></blockquote></div><br class=""></div></blockquote></div><br clear="all" class=""><div class=""><br class=""></div>--<span class=""> </span><br class=""><div dir="ltr" class=""><div dir="ltr" class=""><div class=""><div dir="ltr" class=""><div class=""><div dir="ltr" class=""><div class="">What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br class="">-- Norbert Wiener</div><div class=""><br class=""></div><div class=""><a href="http://www.cse.buffalo.edu/~knepley/" target="_blank" class="">https://www.cse.buffalo.edu/~knepley/</a></div></div></div></div></div></div></div></div></div></blockquote></div><br class=""></div></div></div></blockquote></div><br clear="all" class=""><div class=""><br class=""></div>--<span class="Apple-converted-space"> </span><br class=""><div dir="ltr" class="gmail_signature"><div dir="ltr" class=""><div class=""><div dir="ltr" class=""><div class=""><div dir="ltr" class=""><div class="">What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br class="">-- Norbert Wiener</div><div class=""><br class=""></div><div class=""><a href="http://www.cse.buffalo.edu/~knepley/" target="_blank" class="">https://www.cse.buffalo.edu/~knepley/</a></div></div></div></div></div></div></div></div></div></blockquote></div><br class=""></div></body></html>