Partitioned FSI-Coupling with Open-Source Technology

Partitioned FSI-coupling with Open-source technology.

Pankaj Daga, Ulrich Heck, Martin Becker DHCAE Tools GmbH

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Copyright © ESICopyright Group, ©2016. ESI Group, All rights 2016. reserved. All rights reserved. 4th ESI4 OpenFOAMth OpenFOAM UserUser Conference Conference 2016 2016 – October– October 11 11 &- 12 –- Cologne, Germany DHCAE Tools GmbH, Germany

Simulation solutions based on Open-source solver technology

Engineering: Software User Support Standard/ Training: CFD services with Customised: OpenFOAM® and OpenFOAM®/our CalculiX GUIs (CastNet), Extensions Extensions

This offering is not approved or endorsed by ESI Group, the producer of the OpenFOAM® software and owner of the OPENFOAM® and OpenCFD® trade marks.

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• Introduction

• Types of FSI-coupling

• FSI-coupling using Open-source technology

• Example/Validation

• Conclusion

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Partitioned Coupling: Individual solution of fluid and structural part.

Monolithic Coupling: Combined solution of fluid and structural part with common matrix.

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•Incompressible fluid/ soft structure •Hyperelastic material •Highly dynamic f~100- 200Hz •Wall contact Error: Pressure/Flow ~ 10 %

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Copyright © ESI Group, 2016. All rights reserved. 4th ESI OpenFOAM User Conference 2016 – October 11 & 12 – Cologne, Germany Partitioned Coupling •OpenFOAM as CFD solver. •CalculiX/Abaqus as structural solver Advantage OpenFOAM: –Flexible solver structure –Mapping tools (sample) –Point based mesh-motion Objectives: –Static applications –Use of OpenFOAM functionalities –Extension/Development for transient applications

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OpenFOAM (CFD) Mesh update Flow field

Pressure, wall shear stress

Force mapping No

: Called, monitored andmonitored : Called, CalculiX (CSM)

Displacement

Coupler

- controlled by RunGui by controlled FSI Converged (Forces/Displacements)?

Yes

Data conversion (vtk)-postprocessing: ParaView

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Copyright © ESI Group, 2016. All rights reserved. 4th ESI OpenFOAM User Conference 2016 – October 11 & 12 – Cologne, Germany Pressure/ Wall shear stress • Determine pressure and wall P, Wss P, Wss shear stress on FSI-Interface P, Wss P, Wss • Use of sample utility for pressure values and wallShearStress utility for shear stress values

• Triangulation of surface mesh

• Use of triangulated element mid points as sampling point.

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• Integration to get forces.

• Distribution of forces on nodes.

• Computation of displacements with Abaqus/CalculiX.

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• Linear Element

 Triangular element 1 퐹 = 퐹 푛표푑푒 3 푇표푡푎푙

 Quad element 1 퐹 = 퐹 푛표푑푒 4 푇표푡푎푙

• Quadratic Element

 Triangular element 퐹푐표푟푛푒푟_푁표푑푒 = 0 1 퐹 = 퐹 푚푖푑_푁표푑푒 3 푇표푡푎푙

 Quad element 1 퐹 = - 퐹 푐표푟푛푒푟_푁표푑푒 12 푇표푡푎푙 1 퐹 = 퐹 푚푖푑_푁표푑푒 3 푇표푡푎푙 www.esi-group.com 11

• Interpolation method P2 P1

• Barycentric Interpolation: • Weighted based on surface area • Special treatment of the corner points.

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• Relaxation possibilities: • Forces • Displacements

• Different re-mesh options • Full • Partial

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Displacement from CalculiX

Old Mesh Re-Mesh

pointMotionU Barycentric surfaceMeshTriangulate Interpolation moveDynamicMesh snappyHexMesh Mesh update pimpleDyMFoam No

Mesh Quality Check?

Yes

Next FSI Iteration

Advantage: large displacement can be realized

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• Division of FSI-area in small region.

• Use of Arbitrary Mesh Interface(AMI).

• Re-mesh for only selected region, reduces time required.

• mergeMesh for complete fluid area.

Advantage: Complex geometry need not to be fully re-meshed.

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Results Mok

Results- OpenFOAM- Mok CalculiX

Displacement A 0.061m 0.06047m Displacement B 0.0225m 0.021557m

Daniel Pinyen Mok: „Partitionierte Lösungsansätze in der Strukturdynamik und der Fluid-Struktur-Interaktion“, PHD-Thesis, 2001.

Validated with other commercial OpenFOAM CalculiX Coupling FSI-tools. www.esi-group.com 19

Copyright © ESI Group, 2016. All rights reserved. 4th ESI OpenFOAM User Conference 2016 – October 11 & 12 – Cologne, Germany Technical Application Extrusion-Tool Fluid domain: Approx. 4 Mio fluid cells Structural domain: Approx. 25 000 quad elements

Currently used in an EU funded Cloud- Computing project for FSI-simulations of polymer extrusion dies.

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• FSI-setup for both OpenFOAM and CalculiX in a single case definition.

• Automated workflow based on input in FSI property file.

• Export of intermediate data for stl file generation.

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Copyright © ESI Group, 2016. All rights reserved. 4th ESI OpenFOAM User Conference 2016 – October 11 & 12 – Cologne, Germany Conclusion Current status: • Partitioned FSI-coupling for static applications • for shells and solids • With Re-meshing (Full/Partial)

• Validation with literature examples and commercial software

• With CalculiX: Completely Open-source • With Abaqus: Complex non-linear effects

• GUI-Integration with CastNet/RunGui

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Parts of the project received public fundings: • Zentrales Innovationsprogramm Mittelstand (ZIM): „Methods for simulating particle retention at porous structures and its effects on flow resistance“.

• Seventh Framework Programme: The research leading to these results has received funding from the European Community's Seventh Framework Programme (FP7-2013-NMP-ICT-FoF) under grant agreement n° 609100.

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