The Power of Water - FSI Simulations in the Automotive Industry

Transcription

1 optimises your technology The Power of Water - FSI Simulations in the Automotive Industry STAR Global Conference 2016 Prague Mattias Wångblad FSD Ulf Engdar FSD Fredrik Carlsson FSD Alper Cesur VCG FS Dynamics Sweden AB Mölndalsvägen 24 SE Göteborg +46 (0)

2 Outline Background Validation of FSI setup Plastic deformations of plate Summary Future work

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4 Background Strong co-operation between FS Dynamics and Volvo Car Group Long history of splash simulations at VCG Driving through water creates a lot of splash! Might cause problem for components due to contamination or as studied here; mechanical failures Fluid-Structural Interaction (FSI)

5 Validation of FSI setup Exterior plate outside of vehicle Validation of the FSI setup Comparison of deformations against experiments

6 CFD Setup Run in STAR-CCM+ Co-simulation with SIMULIA Abaqus FEA Trimmed cell meshes ~10M, 40M cells depending on case Morphing mesh LES Multiphase, VOF with HRIC Time step size ~0.1ms

7 Rendering David Frisk First step to make sure splash works Force comparison against experiment

8 Exterior polycarbonate plate

9 Deformation [mm] Displacements 30 SIMULATIONS WITH DIFFERENT MATERIAL PROPERTIES Time [s] Similar behaviour, peak and mean within 10% of average experiments Material properties very important in FSI, usually wide range in specifications

10 The reason why 2-way coupling is important way 2-way Displacement Force way coupling, plate experienced as static by STAR-CCM+ More water hitting the component, due to lack of deflection

11 Plastic deformation To see the long term risk for structural failure FEM model with plastic deformations Driving through a groove filled with water

12 Aluminium plate underneath car A middle B

13 The power of splash

14 Mesh setup Morphing mesh Interface with surrounding domain

15 Aluminium plate under car Abaqus model

16 Aluminium plate under car To the left water splash in STAR-CCM+. To the right plastic deformation in Abaqus. Fluctuations necessary to continue plastification

17 DISPLACEMENT [MM] Aluminium plate under car TIME [S] Good correlation with large splash wave Not modelling entering of groove Experiment data not very subtle measurements after 40mm

18 Final deformation A middle B Experiments: A: 35 +/- 3 mm B: 39 +/- 2 mm Simulation: A: 39 mm B: 42 mm

19 Summary Good possibility to simulate the damages from splash with co-simulation between STAR-CCM+ and Abaqus Good agreement with experiments Aiming to find indications for failures early in design phase Predict risk for mechanical failures

20 Future work The splash angle and the associated pressure forces and deformation of the component is expected to be influenced by following parameters: Pattern of tyre Tyre dynamics; MRF and Overset mesh Contact patch between the tyre and ground Consideration of the actual geometry of the gutter/groove Consideration of rigid body motion of the vehicle