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

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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_at_tu-bs.de
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Agenda

• Introduction
• Airplane Design
• Tool Integration
• Applications
• Conclusions / Outlook

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Introduction

• Institut für Flugzeugbau und Leichtbau (IFL)
• Institute for Aircraft Design and Lightweight
  Structures
• Technical University Braunschweig
• Prof. Dr.-Ing. Peter Horst

• 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

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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

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Airplane Design
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Airplane Design
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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

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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

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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 B
Project partner A
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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 B
Project partner A
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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

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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

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Tool Integration
Visualization pipeline of vtk
Reader SourceObject() DataObj1
Reader.GetOutput() Filter ProcessObject() Filter
.SetInput( DataObj1 ) DataObj2
Filter.GetOutput() DataObj2.Update()
SourceObject

• 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

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

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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/networ
  ks
• 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.

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Tool Integration Graphical User
Interface
Pipeline
Object Editor
Object Documentation
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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

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Application
Aeroelasticity

• Mapping between different surface-grids
• State-/Flux-transfer by
• Domain- Decomposition approach
• Reference geometry

• Deflection transfer by vtkThinPlateSplineTransform

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Application
Aeroelasticity

• Reference geometry
• Euler code
• MSC/Nastran
• Coupling iteration
• for the
• equilibrium state

• Deflection transfer by vtkProbeFilter and
  self-developed hybride techniques

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Application
Aeroelasticity

• A340 Wing
• Incomplete FEM model

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Application
Airport Environment

• Visualization of the design parameters of a new
  configuration

• Geometry
• Simulation results

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Application
Airport Environment

• Simulation of vehicle motions in the airport
  environment (compatibility)

• Different dynamic models
• Ground service simulation with MissionLab

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Application
Airport Environment

• Flight dynamic simulation with JSBSim from the
  FlightGear-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

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Application
Fluid-Structure-Interaction

• ASTRA/IMENS Project - Coupled
  thermal-mechanical analysis

Mach Number

• Flap-gap model
• Reenrtry X38 / CRV
• Navier-Stokes-Code
• coupled with
• FEM-Code
• Comparison with wind tunnel experiments

Stanton Number
Structural Temperature
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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)
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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)
• ...

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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