{"id":425964,"date":"2025-03-17T22:19:08","date_gmt":"2025-03-17T22:19:08","guid":{"rendered":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/preserving-composite-layer-properties-in-pre-stressed-2-way-fsi\/"},"modified":"2025-03-17T22:19:08","modified_gmt":"2025-03-17T22:19:08","slug":"preserving-composite-layer-properties-in-pre-stressed-2-way-fsi","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/preserving-composite-layer-properties-in-pre-stressed-2-way-fsi\/","title":{"rendered":"Preserving Composite Layer Properties in Pre-Stressed 2-Way FSI"},"content":{"rendered":"

<p class=”MsoNormal” style=”text-align: justify;”><span lang=”EN-US” style=”mso-ansi-language: EN-US;”>Hi everyone,<\/span><\/p><p class=”MsoNormal” style=”text-align: justify;”><span lang=”EN-US” style=”mso-ansi-language: EN-US;”>For my master’s thesis, I’m running a 2-way FSI simulation of a composite airplane wing in Ansys. The wing structure consists of ~25 parts, modeled in Workbench using ACP-Pre to assign composite material layers. The ACP-Pre setup can be linked to a Static or Transient Structural module for structural analysis, while a Fluent module handles the CFD. System Coupling connects both for the 2-way FSI.<\/span><\/p><p class=”MsoNormal” style=”text-align: justify;”><span lang=”EN-US” style=”mso-ansi-language: EN-US;”>In System Coupling, I quickly get the following error from the Fluent module: “Update-Dynamic-Mesh failed. Negative cell volume detected”. From what I gathered online, this is caused by too large mesh deformations during Fluent’s remeshing in between iterations. The usual solutions are either coarsening the mesh (which isn’t really an option for me) or reducing the time step. However, I would need an extremely small time step to have it work, which would cause the simulation to take an extremely long time.<\/span><\/p><p class=”MsoNormal” style=”text-align: justify;”><span lang=”EN-US” style=”mso-ansi-language: EN-US;”>A potential workaround I found is doing a pre-stressed FSI:<\/span><\/p><\/p>\n

    <li class=”MsoNormal” style=”text-align: justify; mso-list: l0 level1 lfo1; tab-stops: list .5in;”><span lang=”EN-US” style=”mso-ansi-language: EN-US;”>Run a 1-way FSI (Fluent → Static Structural) to obtain an initial deformation.<\/span><\/li>\n

    <li class=”MsoNormal” style=”text-align: justify; mso-list: l0 level1 lfo1; tab-stops: list .5in;”><span lang=”EN-US” style=”mso-ansi-language: EN-US;”>Use the deformed geometry to start the 2-way FSI analysis.<\/span><\/li>\n<\/ol>\n

    <p class=”MsoNormal” style=”text-align: justify;”><span lang=”EN-US” style=”mso-ansi-language: EN-US;”>This approach is described in these forum posts:<\/span><\/p><ul style=”margin-top: 0in;” type=”disc”><li class=”MsoNormal” style=”text-align: justify; mso-list: l1 level1 lfo2; tab-stops: list .5in;”><span lang=”EN-US” style=”mso-ansi-language: EN-US;”>How to include a pre-stressed initial state in 2-way FSI<\/span><\/a><\/li>\n

    <li class=”MsoNormal” style=”text-align: justify; mso-list: l1 level1 lfo2; tab-stops: list .5in;”><span lang=”EN-US” style=”mso-ansi-language: EN-US;”>How to apply a pre-stressed geometry in FSI<\/span><\/a><\/li>\n<\/ul>\n

    <p class=”MsoNormal” style=”text-align: justify;”><span lang=”EN-US” style=”mso-ansi-language: EN-US;”>The problem: When importing the deformed geometry from Static Structural into Transient Structural, it seems to lose the composite ply definitions from ACP-Pre. This results in incorrect structural properties, making the solution meaningless.<\/span><\/p><p class=”MsoNormal” style=”text-align: justify;”><span lang=”EN-US” style=”mso-ansi-language: EN-US;”>My question:<\/span><\/strong><\/p><p class=”MsoNormal” style=”text-align: justify;”><span lang=”EN-US” style=”mso-ansi-language: EN-US;”>Is there a way to export the deformed composite plies from Static Structural into Transient Structural? Or could I use MAPDL to extract stiffness properties from each part and reapply them in Transient Structural?<\/span><\/p><p class=”MsoNormal” style=”text-align: justify;”><span lang=”EN-US” style=”mso-ansi-language: EN-US;”>Or are there any other solutions which allow me to use a larger time step, without getting the “Negative cell volume” error?<\/span><\/p><p class=”MsoNormal” style=”text-align: justify;”> <\/p><p class=”MsoNormal” style=”text-align: justify;”><span lang=”EN-US” style=”mso-ansi-language: EN-US;”>Any suggestions would be greatly appreciated!<\/span><\/p><\/p>\n","protected":false},"template":"","class_list":["post-425964","topic","type-topic","status-publish","hentry","topic-tag-acp-pre","topic-tag-fsi","topic-tag-prestress","topic-tag-system-coupling"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t