Transcription
Integrating multi-body simulation and CFD:toward complex multidisciplinary design optimisationFederico UrbanESTECOItalyCourtesy ofMartin MühlmeierAUDIGermanyStefano PieriDepartment of EnergeticsUniversity of TriesteItaly
Presentation OutlineThis work show-cases how to carry out a multi-disciplinary design process couplingall the tools generally involved in a complete multi-body analysis.The integration will be managed by modeFRONTIER MDO packageThe race-car:Audi R8Courtesy ofThe track:Le Mans
Presentation Outline Courtesy ofOptimisation Goals;The physics behind the problem: Aerodynamics Multi-bodyDynamics;The numerical analyses for simulating the real-life complexity: Tools;How to put together the numerical tools for achieving the result:Methods;Optimisation Results.
GoalsINCREASE VEHICLE PERFOMANCESObjective:Input Variables:Courtesy ofMinimization of Lap-timeGeometrical Entities
AerodynamicsAerodynamics is a crucial issue in thedesign of a high-speed vehicle.It is useful and “safer” to simulate inadvance the Aerodynamics atdifferent race scenariosCourtesy ofPorsche911-GTO (McNish) Le Mans '98
Numerical AnalysesFor achieving a complete and reliable numerical simulation we shouldconsider the impact of the aerodynamic forces on the mechanicalbehaviour of the vehicleIn practice, carry out the coupled numerical solution with CFD tool(CFX) and Multi-Body tool (Adams) using a three-dimensional model.Courtesy of
ToolsThe Numerical Tools SCENARIO: 3-D Analysis CAE Tools:––––– Courtesy ofCatia V5 : Parametrization.Icem CFD 4.3: Mesh Generation.CFX 5.6: Fluid-Dynamics Simulation.MSC-Adams: Multi-Body Dynamics Simulation.modeFRONTIER: “the wrapper”Multiple CFD analyses at various positions of the car
Tools: Catia V5The parametric model: Coordinates of the fundamental points of thediffuser (Xpar, Zpar). Inclination and the Height of the rear wingprofile (H2, Alpha).Courtesy of
Tools: Icem CFD 4.3The finite-element model: Hybrid mesh (tetra prisms) - 3 millions cellsCourtesy of
Tools: CFX 5.6 - Boundary conditionsINLETWall no slip v 0Wall no slip (v 44 m/s)v 44 m/sRotating wheelsCourtesy ofSimmetryOUTLET
Tools: CFX 5.6 - ResultsVelocityCourtesy ofPressure
Tools: MSC-ADAMS CarMotorsport.Simulating vehicle dynamics The global model is represented by means of agroup of mechanical elements with specificcharacteristics. The structure of the complete car model has apyramidal layout.Courtesy of
Methods: The Idea!Original GeometryCFD SimulationsAerodynamic MatricesNew GeometryDynamic SimulationOptimizationAlgorithmLAP timeCourtesy of
Methods: The Design FlowParmacro.CATScriptCATIAH2, Alfa, Xpar, ZparCourtesy ofAUDI box.modelICEM CFDcfx5macroCFXADAMSLAP time
Methods: Design Process RequirementsIn order to achieve the most reliable map of aerodynamic forces tobe used as boundary conditions along the multi-body analyses, eachdesign is evaluated in 12 different vehicle body positionsCourtesy of
Methods: The Design FlowD.A.C.E. (Design and analysisof computer experiment),external Response SurfaceModellerH1, BetaBodyn 12Parmacro.CATScriptCATIAH2, Alfa, Xpar, ZparAUDI box.modelICEM CFDCFXifMatrix 3x4DACEADAMSMatrix 6x8With 12 simulations, it is possible to extrapolate the complete 6x8 matrix of theaerodynamic forces required by ADAMS.Courtesy ofLAP time
Methods: The Design FlowH1, BetaBodyn 12Parmacro.CATScriptCATIAH2, Alfa, Xpar, ZparAUDI box.modelICEM CFDCFXifMatrix 3x4modeFRONTIERCourtesy ofDACEADAMSMatrix 6x8LAP time
Methods: Process Itegration withmodeFRONTIERCourtesy of
Methods: Process Itegration withmodeFRONTIERCourtesy of
Methods: Complete Process FlowCourtesy of
Methods: Input Parameters RangesParameterLower BoundUpper BoundXpar (mm)27362886Zpar (mm)-244,124-94,124Alfa (degrees)-22H2 (mm)-5050 mmCourtesy of
Results: History Chart – Lap Time vs. DesignIDRESULTDesign 17 improves2,36 sec. the lap timeCourtesy ofSimplex Algorithm
Results: CFD Plots – Original vs OptimalMinimum heightMaximum inclinationCd coefficient: -15 %Cl coefficient: 6.0 %Cd coefficient: -11 %Cl coefficient: -12 %Courtesy of
Results: Dynamics Diagrams – Original vsOptimalVELOCITYOptimalOriginalCourtesy ofFUEL CONSUMPTION
Conclusive remarks modeFRONTIER managed a real-life multi-disciplinary optimization problem in aeasy-to-use environment. CATIA, ICEM, CFX, ADAMS have been integrated in aprocess integration framework.The design chain worked successfully achieving virtually 2 seconds reduction ofthe lap time.Each the Process Integration issue and the Design Optimization problemhave been reliably solvedCourtesy of
CATIA ICEM CFD CFX if ADAMS LAP time D.A.C.E. (Design and analysis of computer experiment), external Response Surface Modeller DACE With 12 simulations, it is possible to extrapolate the complete 6x8 matrix of the aerodynamic forces required by ADAMS. Courtesy of. Methods: The Design Flow Parmacro.CATScript
