On 8/7/22 06:00, Simon wrote:
the fourth-order referential deviatoric tensor as returned byPhysics::Elasticity::StandardTensors <https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.dealii.org%2Fcurrent%2Fdoxygen%2Fdeal.II%2FclassPhysics_1_1Elasticity_1_1StandardTensors.html&data=05%7C01%7CWolfgang.Bangerth%40colostate.edu%7Cc7d0b41aa97a4f5bbf6a08da786c79b6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C637954704552090273%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=u9Z1RfLeZdT2vdeD7%2BNYIXWA8h%2Bkvtdre4KIewAI0ws%3D&reserved=0>< dim >::Dev_Pincludes the fourth-order referential/spatial unit *symmetric* tensorPhysics::Elasticity::StandardTensors <https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.dealii.org%2Fcurrent%2Fdoxygen%2Fdeal.II%2FclassPhysics_1_1Elasticity_1_1StandardTensors.html&data=05%7C01%7CWolfgang.Bangerth%40colostate.edu%7Cc7d0b41aa97a4f5bbf6a08da786c79b6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C637954704552090273%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=u9Z1RfLeZdT2vdeD7%2BNYIXWA8h%2Bkvtdre4KIewAI0ws%3D&reserved=0>< dim >::S = identity_tensor <https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.dealii.org%2Fcurrent%2Fdoxygen%2Fdeal.II%2Fsymmetric__tensor_8h.html%23ab3e890348aa219805e84f7d367e098c3&data=05%7C01%7CWolfgang.Bangerth%40colostate.edu%7Cc7d0b41aa97a4f5bbf6a08da786c79b6%7Cafb58802ff7a4bb1ab21367ff2ecfc8b%7C0%7C0%7C637954704552090273%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=3bQQR2Em7YyxuQuohp19IsBWntxKehAhRzin%2F0GFlBs%3D&reserved=0><dim>().In the literature, for instance G. A. Holzapfel: "Nonlinear solid mechanics. A Continuum Approach for Engineering" (2007),however, the general fourth-order unit tensor I_{ijkl} = delta_{ik} delta_{jl} is used to compute Dev_P.I implemented a hyperelastic material model with a volumetric / isochoric split of the strain energy function and it only converges when using 'S' - as dealii does it. Using the general fourth-order unit tensor to define Dev_P, my solver does not converge at all.Is it neccessary to use 'S' due to the way dealii stores and accesses the elements of symmetric tensors?
The question is what you apply I or S to. If you apply them to symmetric rank-2 tensors, then they are the same. If you apply them to non-symmetric tensors, then they are not.
Best
W.
--
------------------------------------------------------------------------
Wolfgang Bangerth email: bange...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/
--
The deal.II project is located at http://www.dealii.org/
For mailing list/forum options, see
https://groups.google.com/d/forum/dealii?hl=en
---
You received this message because you are subscribed to the Google Groups "deal.II User Group" group.
To unsubscribe from this group and stop receiving emails from it, send an email to dealii+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/dealii/9c3d5b70-7fe0-9684-0f7e-c608baf72c50%40colostate.edu.
