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<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>
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<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="">
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<div style="overflow-wrap: break-word;" class="">Hello,
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<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>
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<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>
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<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>
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<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>
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<div class="">No, it would have to be coded.</div>
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<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>
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<div class="">No, it would have to be coded.</div>
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<div class="">4. Is there a mechanism by which you can classify existing elements as cohesive elements?</div>
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<div class="">See 1.</div>
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<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>
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<div class="">There is nothing for non-conforming interfaces.</div>
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<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>
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<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>
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<div>I definitely concur with this and would be happy to help…</div>
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<div>Blaise</div>
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<div style="margin: 0px;" class="">A.K. & Shirley Barton Professor of Mathematics</div>
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