<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="">Hello,<div class=""><br class=""></div><div class="">Thank you both for your comprehensive replies.</div><div class=""><br class=""></div><div class="">Matt:<br class=""><div class="">Thanks for the rundown, I will take a look at PyLith and its cohesive element impls.</div><div class=""><br class=""></div><div class="">Blaise:</div><div class="">The project is still in very early stages as you can tell, so everything is up in the air. Currently we are weighing using a cohesive element approach vs an element extinction approach but we can certainly add a variational model into the mix. We had leaned towards the cohesive element approach as we also need to link Quantum Monte Carlo generated data to the model, which seemed logically the easiest to do with cohesive elements. Are there any examples of your codes online? The only reference I could find online was in this link <a href="https://www.math.lsu.edu/~bourdin/defectmechanics/" class="">https://www.math.lsu.edu/~bourdin/defectmechanics/</a> </div><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 Jun 19, 2020, at 10:15 AM, Blaise A Bourdin <<a href="mailto:bourdin@lsu.edu" class="">bourdin@lsu.edu</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div 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=""><br class="Apple-interchange-newline"><br class=""><blockquote type="cite" class=""><div class="">On Jun 18, 2020, at 5:28 AM, 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" class=""><div dir="ltr" class="">On Wed, Jun 17, 2020 at 4:05 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 class="" style="overflow-wrap: break-word;">Hello,<div class=""><br class=""></div><div class="">I am looking to perform large scale fracture and crack propagation simulations and have a few questions regarding PETSc support for this. Specifically I am looking for cohesive surface element support with a few twists:</div><div class=""><br class=""></div><div class="">1. Is there support for zero thickness surface elements? For example modeling virtually flat patches of adhesives holding together two larger structures being pulled apart.</div></div></blockquote><div class=""><br class=""></div><div class="">This is how PyLith works: <a href="https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fgeodynamics%2Fpylith&data=02%7C01%7Cbourdin%40lsu.edu%7Ca6ad0b6927f7495344ad08d813729554%7C2d4dad3f50ae47d983a09ae2b1f466f8%7C0%7C0%7C637280730142259699&sdata=T5m2PUCrxF4%2BPYYnqvp6%2F8pLQeH0U7MjqADvwkFjGYY%3D&reserved=0" originalsrc="https://github.com/geodynamics/pylith" shash="iWuI+CNrVfh3e7/gBfxWwDPMMx6uEv58WSeBHhZc5AHb7EdO6U4v2H4tv/aMb0VI9oa5JBmhK9odVUDTKBVx43Gm/Dae8wmQbKOedN4+ICYF/9DDPAMYGQaF+HXwrcSxlpBe9IdXiOXptT7qVQcOgQT93lT3APLwUvDvgplFTTA=" class="">https://github.com/geodynamics/pylith</a></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="" style="overflow-wrap: break-word;"><div class="">2. Is there support for “joining” two possibly distinct meshes with cohesive surface elements? For example say I have two distinct cylinders representing fibers which would “touch" to form an X shape.</div></div></blockquote><div class=""><br class=""></div><div class="">No, it would have to be coded.</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="" style="overflow-wrap: break-word;"><div class="">3. In a similar vein, is there support for a mesh to fracture entirely along a crack formed through the cohesive elements? Imagine the aforementioned X configuration separating entirely into two separate cylinders again.</div></div></blockquote><div class=""><br class=""></div><div class="">No, it would have to be coded.</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="" style="overflow-wrap: break-word;"><div class="">4. Is there a mechanism by which you can classify existing elements as cohesive elements?</div></div></blockquote><div class=""><br class=""></div><div class="">See 1.</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="" style="overflow-wrap: break-word;"><div class="">5. Is there an already implemented way of imposing tie-constraints between independent meshes? This would potentially be used to tie high order cohesive cells which would have a non-conforming interface to the “regular” mesh.</div></div></blockquote><div class=""><br class=""></div><div class="">There is nothing for non-conforming interfaces.</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="" style="overflow-wrap: break-word;"><div class="">From googling I have come across DMPlexCreateHybridMesh(), DMPlexConstructCohesiveCells(), and DMPlexCreateCohesiveSubmesh(). While these do implement cohesive cells these functions don’t at first glance seem to allow one to implement the above. </div></div></blockquote><div class=""><br class=""></div><div class="">Having worked with cohesive elements for more than a decade, I would be cautious about a new code using them for fracture. To me, it appears</div><div class="">that variational fracture codes, like those from Blaise Bourdin and J. J. Marigo's group have much better geometric flexibility, and Maurini's work on</div><div class="">the solver clears up the hardest part.</div></div></div></div></blockquote><div class=""><br class=""></div><div class="">I definitely concur with this and would be happy to help…</div><div class=""><br class=""></div><div class="">Blaise</div><div class=""><br class=""></div><div class=""><span class="" style="orphans: 2; widows: 2; -webkit-text-decorations-in-effect: none;">-- </span></div></div><div class="" 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;"><div dir="auto" class="" style="caret-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;"><div dir="auto" class="" style="caret-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;"><div dir="auto" class="" style="caret-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;"><span class="Apple-style-span" style="border-collapse: separate; font-variant-ligatures: normal; font-variant-east-asian: normal; font-variant-position: normal; line-height: normal; border-spacing: 0px; -webkit-text-decorations-in-effect: none;"><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-variant-east-asian: normal; font-variant-position: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; border-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-stroke-width: 0px;"><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><span class="Apple-style-span" style="border-collapse: separate; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-variant-east-asian: normal; font-variant-position: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; border-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-stroke-width: 0px;"><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px; font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-variant-east-asian: normal; font-variant-position: normal; font-weight: normal; letter-spacing: normal; line-height: normal; -webkit-text-decorations-in-effect: none; text-indent: 0px; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px;"><div class="" style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div class="" style="margin: 0px;">A.K. & Shirley Barton Professor of Mathematics</div><div class="" style="margin: 0px;">Adjunct Professor of Mechanical Engineering</div><div class="" style="margin: 0px;">Adjunct of the Center for Computation & Technology</div><div class="" style="margin: 0px;">Louisiana State University, <span class="" style="-webkit-text-decorations-in-effect: none;">Lockett Hall Room 344, </span><span class="" style="-webkit-text-decorations-in-effect: none;">Baton Rouge, LA 70803, USA</span></div><div class="" style="margin: 0px;"><span class="" style="-webkit-text-decorations-in-effect: none;">Tel. +1 (225) 578 1612, Fax +1 (225) 578 4276 Web </span><span class="" style="-webkit-text-decorations-in-effect: none;"><a href="http://www.math.lsu.edu/~bourdin" class="">http://www.math.lsu.edu/~bourdin</a></span></div></div></span></div></span></div></span></div></span></div></div></div></div></div></blockquote></div><br class=""></div></div></body></html>