The Use of Open Source Software for Integrated Design and Analysis Tools

1. The Use of Open Source Software forIntegrated Design and Analysis Tools Aerospace PDE 2002 NASA-ESA Workshop Matthias C. Haupt, P. Horst Institut für Flugzeugbau und Leichtbau Technische Universität Braunschweig Hermann-Blenk-Strasse 35 D-38108 Braunschweig Germany m.haupt@tu-bs.de

2. Agenda • Introduction • Airplane Design • Tool Integration • Applications • Conclusions / Outlook Institut für Flugzeugbau und Leichtbau, TU Braunschweig

3. Institut für Flugzeugbau und Leichtbau (IFL) Institute for Aircraft Design and Lightweight Structures Technical University Braunschweig Prof. Dr.-Ing. Peter Horst Introduction • Environment: • Faculty of mechanical engineering • Member of the Graduate College Interaction of Fluids and Structures • National and european research projects • Cooperations with institutes and industry • Remarks: • We use standards • We are looking into the STEP/XML direction • Open Source approach is interesting • Fields of activity • Lightweight structures • Numerical simulation techniques • Stability, buckling • Damage tolerance • Fluid-structure interactions • Composites, fibre reinforced material • Material testing • Component and full scale testing • Airplane design and optimization Institut für Flugzeugbau und Leichtbau, TU Braunschweig

4. Airplane Design • Aim: • Determination of the optimal shape for a defined transportation task by a multidisciplinary analysis • … classical criteria are the DOC • Tasks: • Proof of feasibility of the initial configuration • Optimization of the initial configuration • Assessment of changes of the transportation task • Estimation of the effects of new technologies • Comparison with alternative configurations at the same analysis precision Institut für Flugzeugbau und Leichtbau, TU Braunschweig

5. Airplane Design Institut für Flugzeugbau und Leichtbau, TU Braunschweig

6. Airplane Design Institut für Flugzeugbau und Leichtbau, TU Braunschweig

7. Airplane Design • Challenges: • Identification and analysis of problems already in concept phase • Early simulation of critical difficulties of the actual airplane design with visualization: • Emergency evacuation • Dynamic behaviour of the structure / crash • Retraction of the landing gear • Flightdynamic simulation of critical flight manouvers • Consideration of further nonclassical aspect of market success • Cabin design acceptance of the passengers • Ground services (use of standard service vehicles, minimal grounding times) • Compatability with the infrastructure of the airports Institut für Flugzeugbau und Leichtbau, TU Braunschweig

8. Airplane Design • Difficulties of the computer aided airplane design: • High complexity of the entire problem with extensive data • Different self developed and commercial modelling and analysis tools • Intensive data transfer between tools with diverse interface standards • Transition from simple to complex modelling and analysis tools • Manual execution of the workflow is time consuming and error-prone • Need for a flexible tool integration: • Users are students, engineers and scientists (acceptance) • Different projects ( duration: 0.3 - 6 years ) • Numerous of inhouse and commercial tools • Easy to learn, to handle and to understand • ... at low costs ... for a long period • ... different levels of complexity • ... reuse of existing code ... teaching the techniques Institut für Flugzeugbau und Leichtbau, TU Braunschweig

9. Airplane Design Tool Integration • State of the IFL tools today High Fidelity Simulation PrADO Preprocessor A PrADO-DB Module A Analysiscode A DB1 Module B Preprocessor B DB2 Analysiscode B Module C DB3 Module D Project Analysis Environment Analysiscode X Preliminary Aicraft Design Project partner A Project partner B Institut für Flugzeugbau und Leichtbau, TU Braunschweig

10. Airplane Design Tool Integration • ... the next step with STEP (?) • Better exchange of data • and methods !!! PrADO Preprocessor A Datamanagement STEP / XML (?) Module A Analysiscode A Module B Preprocessor B Analysiscode B Module C Module D Analysiscode X Integration Environment Project partner A Project partner B Institut für Flugzeugbau und Leichtbau, TU Braunschweig

11. Airplane Design • Objectives of our development: • Automation and integration of the workflow • Flexible data transfer between tools • Integration of different source codes as well as executables • Simplicity, clearness, flexibility and robustness of the integration approach • Efficient rapid prototyping for new (sub-)tasks • Interoperability with project partners • We develop methods to solve our engineering problems • Use of available technologies, standards and tools • . . . suitable Open Source Software • … perhaps a special kind of standard Institut für Flugzeugbau und Leichtbau, TU Braunschweig

12. Tool Integration Basic components of the integration approach: • Python • Object-orientiented scripting language contains elements of traditional languages • Nice, simple syntax • Modular structure • A lot of books • Unix, Windows, ... very stable • Scientific computing • Standard packages of Python • Tkinter: Widgets from Tk for GUI's • Numerical: Vector / matrix objects • Scientific Python: • Scientific tools, MPI, NetCDF, ... • Visualization Tool Kit vtk • 3D computer graphic system, • defines the architecture • compiled kernel C++ • Wrapper for Tcl, Java and Python • Render windows, renderers, actors, • properties, lights, cameras • Data objects (general, grid data), • Process objects (source, filter, mapper) • Reference books and examples • OpenGL ... WinTel, Unix • I/O for VRML, IGES, 3DS, HDF, … • Interface generators • pyfort: Fortran • swig:C, C++ Institut für Flugzeugbau und Leichtbau, TU Braunschweig

13. Tool Integration Visualization pipeline of vtk Reader = SourceObject() DataObj1 = Reader.GetOutput() Filter = ProcessObject() Filter.SetInput( DataObj1 ) DataObj2 = Filter.GetOutput() DataObj2.Update() • Data Objects • represent information • Methods to create, access and delete this information • Methods to obtain characteristic features • STEP-Objects (?) • Process Objects • operates on input data to generate output data • Sources interface to external data (Reader) or generate data from local parameters • Filter require one or more input data objects and generate one or more output data objects • Mapper objects are used to convert data into graphical primitives SourceObject DataObj1 ProcessObject DataObj2 • Pipeline Execution • causes process objects to operate • Implicit control implemented demand-driven • Process object execution if input change • Two-pass process: update and execution Institut für Flugzeugbau und Leichtbau, TU Braunschweig

14. Tool Integration • Integration environment ifls • Extension modules • utk connects vtk and pure Python objects to maintain pipeline mechanisms • usr extents the cababilities of the vtk-process objects • dtn with special data and process objects for geometry and grid generation based on DTNURBS (IGES) and GridLib • stk with process and import/export objects for analysis and simulation in a distributed environment • (Structure: Ansys, MSC, Abaqus, Fluid: HISSS, Flower, Cavecats, Tau) • Graphical editor • Interactive manipulation and visual programming • Analyses the programmed object interactions/networks • Visualize the object interactions ( tree / graph ) • Coding conventions for the automatic generation of the networks, object editors and documentation (html, latex, postscript, pdf). • Python codes are executable without the graphical editor in batch mode, because the GUI is an optional feature. Institut für Flugzeugbau und Leichtbau, TU Braunschweig

15. Tool Integration Graphical User Interface Pipeline Object Editor Object Documentation Institut für Flugzeugbau und Leichtbau, TU Braunschweig

16. Application: Oblique Flying Wing • Geometry wing, fin, wake *.db (PrADO) • Grid *.msh (HISSS) • Results *.sca (HISSS) *.plt (Tecplot) • Aerodynamic Loads • Derivatives • Optimisation • Interactive variations • Students project Institut für Flugzeugbau und Leichtbau, TU Braunschweig

17. Application: Aeroelasticity • Deflection transfer by vtkThinPlateSplineTransform • Mapping between different surface-grids • State-/Flux-transfer by • Domain- Decomposition approach • Reference geometry Institut für Flugzeugbau und Leichtbau, TU Braunschweig

18. Application: Aeroelasticity • Deflection transfer by vtkProbeFilter and self-developed hybride techniques • Reference geometry • Euler code • MSC/Nastran • Coupling iteration • for the • equilibrium state Institut für Flugzeugbau und Leichtbau, TU Braunschweig

19. Application: Aeroelasticity • A340 Wing • Incomplete FEM model Institut für Flugzeugbau und Leichtbau, TU Braunschweig

20. Application: Airport Environment • Visualization of the design parameters of a new configuration • Geometry • Simulation results Institut für Flugzeugbau und Leichtbau, TU Braunschweig

21. Application: Airport Environment • Simulation of vehicle motions in the airport environment (compatibility) • Different dynamic models • Ground service simulation with MissionLab Institut für Flugzeugbau und Leichtbau, TU Braunschweig

22. Application: Airport Environment • Flight dynamic simulation with JSBSimfrom theFlightGear-Project • Complete set of the equation of motion including ground forces and FCS • XML-formatted description of • Servoelasticity • Geometry • Massprops • Aerodynamics • LandingGear • Propulsion • Initial state Institut für Flugzeugbau und Leichtbau, TU Braunschweig

23. Application: Fluid-Structure-Interaction • ASTRA/IMENS Project - Coupled thermal-mechanical analysis MachNumber • Flap-gap model • Reenrtry X38 / CRV • Navier-Stokes-Code • coupled with • FEM-Code • Comparison with wind tunnel experiments Stanton Number Structural Temperature Institut für Flugzeugbau und Leichtbau, TU Braunschweig

24. Application: Fluid-Structure-Interaction Fluid Reader (NetCDF) Structure Reader (*.bdf) Iteration Control Heatflux Transfer Heatflux-Writer (*.bdf) CS-Analysis (Nastran) Temperature-Reader (OP2) Temperature Transfer Heatflux on the coupling surface Temperature-Writer (NetCDF) CFD-Analysis (Tau-Code) Heatflux-Reader (NetCDF) Institut für Flugzeugbau und Leichtbau, TU Braunschweig

25. Application: • ASTRA/IMENS Project • Research project of 5 DLR institutes and the IFL (responsible for coupling techniques) • Goals: • Simulation of thermal-mechanical fluid-structure interactions of hypersonic applications and the experimental validation • Timeaccuracy with respect to thermal behaviour of the structure (2001-2003) • Coupling of the codes Tau (DLR), DavisVol (Astrium) and MSC/Nastran, Ansys • Validation by wind tunnel experiments • Use of the MpCCI – Standardlibrary for direct code coupling via MPI sourcecode availability necessary otherwise file oriented data exchange • Tent workflow management system (DLR) enables distributed / grid computing (CORBA) and access on a LDAP-server for documents • Simple problems: • geometric nonconform models (grids exist) • structural modelling (radiation) • ... Institut für Flugzeugbau und Leichtbau, TU Braunschweig

26. Concluding remarks Outlook Concluding remarks • Open Source approach of ifls is successful at the IFL . . . and makes fun • Finding and evaluation of Open Source Software is not easy • Analysis codes are not considered here • Need for data standards and tools • Interactive examples ... please contact me • Outlook w.r. Open Source • ActionFactory (JULIUS-Project) • for CORBA connectivity • OpenCASCADE for geometric modelling (IGES/STEP), Python bindings in work • Simulation environment Salome (not Open Source up to now) • ... uses Python and vtk as well • PDM environment PGPDM Institut für Flugzeugbau und Leichtbau, TU Braunschweig