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Use of AP203 CAD Data for Engineering Analysis. Hans Peter de Koning - ESA/ESTEC - The Netherlands [email protected] Sandrine Fagot - Simulog - France [email protected] STEP for Aerospace Workshop, NASA-JPL, 16-19 January 2001. Agenda.

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Use of ap203 cad data for engineering analysis

Use of AP203 CAD Data for Engineering Analysis

Hans Peter de Koning - ESA/ESTEC - The Netherlands

[email protected]

Sandrine Fagot - Simulog - France

[email protected]

STEP for Aerospace Workshop, NASA-JPL, 16-19 January 2001


Agenda
Agenda

  • Recap: Usage of CAD to create CAE model

  • Use of AP203 as input

  • Specific application for thermal-radiative CAE (ESARAD)

  • Real world example

  • Further plans

STEP for Aerospace Workshop - NASA-JPL


Recap why use cad geometry to construct cae models
Recap: Why use CAD geometry to construct CAE models?

  • Main objectives:

    • To reduce CAE model construction effort

    • To improve CAE model accuracy and fidelity

    • To transfer and retain product structure and part identification information

    • To improve consistency between CAE models for different engineering disciplines -- CAD model as ‘master digital mock-up’

  • Avoid duplication of effort

    • If it has been modelled in CAD already, why do it again?

    • CAD modeller is probably richer in shape creation functionality than the CAE modeller

STEP for Aerospace Workshop - NASA-JPL


Potential pitfalls with usage of cad for cae
Potential pitfalls with usage of CAD for CAE

  • CAE virtually always needs idealised shape

  • Idealised shape = geometric represention of the object under analysiswhich is appropriate, adequate and sufficiently detailedfor the analysis task at hand

  • Who said engineering is a hard science?

    • Lot of engineering judgement involved

    • Depends on environmental conditions, operational context

    • Depends on engineering life cycle stage

  • Nevertheless, still serious benefits from automated transfer of CAD models to CAE when used with caution

STEP for Aerospace Workshop - NASA-JPL


Use of ap203 for cad cae model transfer
Use of AP203 for CAD - CAE model transfer

  • Nearly all CAD tools now have reliable, good quality AP203 import/export functionality

  • Very attractive for CAE tools to support AP203

    • Good investment: one interface supports all CAD tools

    • First import of AP203 models, later perhaps also export

  • But also problems

    • Most CAE tools can not directly handle all AP203 shapes

      • NURB curves and surfaces, trimming loops, general surface of revolution, etc.

    • Different CAD tools generate different AP203 models

      • For example: many different ways to define a cylindrical surface

NURB =

Non-Uniform

Rational B-spline

STEP for Aerospace Workshop - NASA-JPL


Specific application thermal radiative cae
Specific Application: Thermal-radiative CAE

  • STEP AP203 model import and NURB processing capability for ESARAD

    • R&D activity in 2000 under ESA contract

    • ALSTOM Power Technology Centre (UK)

      • ESARAD tool vendor

      • Management, integration and test

    • Simulog (France)

      • AP203 to ESARAD import translator

    • Formal Software Construction Ltd. (UK)

      • ESARAD NURB surface processing

ESARAD =

Thermal-radiative analysis tool (Monte-Carlo raytracer)

STEP for Aerospace Workshop - NASA-JPL


Usage scenario construct cad ap203 to esarad
Usage scenario: Construct CAD/AP203 to ESARAD

  • Identify CAD model for export

  • Optionally prepare ‘CAE view’ in CAD tool

    • Suppress features, filter small details, flatten hierarchy, remove irrelevant parts

  • Export to STEP AP203 part 21 file

  • Translate AP203 model to native ESARAD model

  • Clean-up and adapt model in ESARAD modeller

  • Add thermal-radiative features

    • meshing, properties, environmental conditions, kinematics, ...

  •  Ready to run ESARAD analysis

STEP for Aerospace Workshop - NASA-JPL


Translate ap203 model to native esarad model 1
Translate AP203 model to native ESARAD model (1)

  • Problem: Mapping of AP203 shapes to ESARAD shapes

    • ESARAD is a surface modeller

      • primitive surface shapes

        • triangular, rectangular, quadrilateral plate

        • disc (-sector, -annulus)

        • cylinder (-segment)

        • cone, sphere, paraboloid (-segment, truncated-)

      • compound surfaces (union of primitive or compound surfaces)

      • boolean cut surfaces (e.g. plate with circular hole)

    • Most CAD tools export AP203 evaluated BREP solid models

      • AP203 CC4, CC5, CC6 models with lots of advanced shapes using NURB, trimming loops, etc.

STEP for Aerospace Workshop - NASA-JPL


Translate ap203 model to native esarad model 2
Translate AP203 model to native ESARAD model (2)

  • Approach

    • Develop heuristic algorithm to recognise / deduct as much as possible primitive shapes in the CAD AP203 export

    • Transfer any remaining shapes as NURB surfaces (with trimming loops)

    • Retain model hierarchy and axis placements

    • Retain shape identification labels, etc.

    • Translator is a stand-alone Unix filter type tool

      • Simple, maintainable, easily extendible to support new output formats

  • Upgrade ESARAD to accept NURB surfaces

    • In shape definition, but also in ray-tracing algorithm!

STEP for Aerospace Workshop - NASA-JPL


Translate ap203 model to native esarad model 3
Translate AP203 model to native ESARAD model (3)

  • Target Catia v4 as first CAD export tool for testing

    • Is most used CAD tool in European space industry

    • Developed Catia generated AP203 test suite

      • Artificial little CAD models containing different ways to construct the primitive shapes (also asking different engineers)

      • Replicated the STEP-TAS test suite using Catia

      • Real world CAD models, including a complete detailed spacecraft CAD model (generates more than 220,000 instances in Part 21 file)

  • Developed heuristic algorithm

    • As much as possible works on generic STEP p42 concepts

    • As little as possible tuned to Catia specific constructs / oddities

  • Outcome is a translator that works!

  • STEP for Aerospace Workshop - NASA-JPL


    Translate ap203 model to native esarad model 4 example from test suite
    Translate AP203 model to native ESARAD model (4)Example from test-suite

    STEP for Aerospace Workshop - NASA-JPL


    Real world example test jig for metop spacecraft
    Real World Example: Test jig for METOP spacecraft

    • METOP: earth observation satellite for Eumetsat

      • Sun-synchronous polar orbit - similar to ERS, Envisat, NASA-EOS

      • Modelled in detail in ESARAD (more than 4000 surfaces)

      • Currently in Phase C/D - Starting thermal balance test predictions

    • Task: Create ESARAD model of test jig

      • Test jig for thermal test, containing cold targets and guard heaters

      • Complicated shape - geometry available in Catia v4

    STEP for Aerospace Workshop - NASA-JPL


    Real world example test jig for metop spacecraft ap203 export from catia
    Real World Example: Test jig for METOP spacecraftAP203 export from Catia

    ISO-10303-21;

    HEADER;

    FILE_DESCRIPTION((''), '1');

    FILE_NAME('METOP FRAME UPPER ',

    '2000-09-25T09:11:38+02:00',

    (''),

    (''),

    'CATIA.STEP INTERFACE',

    'CATIA SOLUTIONS V4 RELEASE 2.0 FR 4.2.0',

    '');

    FILE_SCHEMA(('CONFIG_CONTROL_DESIGN'));

    ENDSEC;

    DATA;

    #1=APPLICATION_CONTEXT('configuration controlled 3D designs of mechanical parts and assemblies');

    #2=APPLICATION_PROTOCOL_DEFINITION('international standard','config_control_design',1994,#1);

    #3=PERSON('111111','Last_Name','First_Name',$,$,$);

    ...

    #650=VERTEX_POINT('NONE',#649);

    #651=B_SPLINE_CURVE_WITH_KNOTS('*CRV273',1,(#652,#653),.UNSPECIFIED.,.U.,.U.,(2,2),(0.00000000000,1.00000000000),.UNSPECIFIED.);

    #652=CARTESIAN_POINT('NONE',(-6663.00000000,2.51588360813,-18.6521285509));

    #16704=TRIMMED_CURVE('*CRV558',#16703,(90.0000000000),(108.628958036),.T.,.UNSPECIFIED.);

    #16705=B_SPLINE_CURVE_WITH_KNOTS('*CRV559',5,(#16706,#16707,#16708,#16709,#16710,#16711,#16712,#16713,#16714,#16715,#16716,#16717),.UNSPECIFIED.,.U.,.U.,(6,3,3,6),(0.00000000000,1.00000000000,1.70960642440,2.31910764281),.UNSPECIFIED.);

    STEP for Aerospace Workshop - NASA-JPL


    Real world example test jig for metop spacecraft translation into esarad definition language
    Real World Example: Test jig for METOP spacecraftTranslation into ESARAD definition language

    /* ESARAD GENERATED FILE FROM STEP AP203 FILE */

    /* ------------------------------------------ */

    /* INFORMATION ON STEP AP203 FILE : */

    /* COMPANY : */

    /* LOCATION : location */

    /* SERVICE : service name */

    /* PERSON : */

    /* PROJECT : project name */

    /* PREPROCESSOR_VERSION : CATIA.STEP INTERFACE */

    /* ORIGINATING_SYSTEM : CATIA SOLUTIONS V4 RELEASE 2.0 FR 4.2.0 */

    /* DATE : 25/9/2000 */

    BEGIN_MODEL MetopFrameUpper

    SHELL generated_id_1;

    generated_id_1 = SHELL_DISC(

    point1 = [ -6.763000, 1.125000, 0.160000],

    point2 = [ -6.762765, 1.125882, 0.159592],

    point3 = [ -6.763000, 1.127516, 0.165447],

    point5 = [ -6.763000, 1.122903, 0.155461]);

    SHELL generated_id_3;

    generated_id_3 = SHELL_NURB_SURFACE(

    u_dim = 9,

    v_dim = 2,

    points = {[-6.727706, 1.254837, 0.093422], [-6.698294, 1.365131, 0.042479],

    [-6.733537, 1.256119, 0.092830], [-6.704126, 1.366413, 0.041887],

    [-6.733537, 1.258635, 0.098277], [-6.704126, 1.368929, 0.047334],

    [-6.733537, 1.261150, 0.103724], [-6.704126, 1.371445, 0.052781],

    [-6.727706, 1.259869, 0.104316], [-6.698294, 1.370163, 0.053373],

    [-6.721874, 1.258587, 0.104908], [-6.692463, 1.368881, 0.053965],

    [-6.721874, 1.256071, 0.099461], [-6.692463, 1.366365, 0.048518],

    [-6.721874, 1.253555, 0.094014], [-6.692463, 1.363850, 0.043071],

    [-6.727706, 1.254837, 0.093422], [-6.698294, 1.365131, 0.042479]},

    weights = {1.000000, 1.000000,

    0.707107, 0.707107,

    1.000000, 1.000000,

    0.707107, 0.707107,

    1.000000, 1.000000,

    0.707107, 0.707107,

    1.000000, 1.000000,

    0.707107, 0.707107,

    1.000000, 1.000000},

    u_degree = 2,

    v_degree = 1,

    u_knots = {0.000000, 0.000000, 0.000000, 1.570796, 1.570796, 3.141593, 3.141593, 4.712389, 4.712389, 6.283185, 6.283185, 6.283185},

    v_knots = {0.150000, 0.150000, 0.275000, 0.275000},

    num_loops = 1,

    loops = {

    DEFINE_NURB_TRIM_LOOP (

    num_curves = 4,

    curves = {

    STEP for Aerospace Workshop - NASA-JPL


    Real world example test jig for metop spacecraft raw ap203 export in esarad

    Produced with first beta version of translator Sep-2000

    All NURB-related shapes removed, because at that stage not yet supported in ESARAD visualisation and ray-tracing

    Still a large amount of useful reference surfaces and points

    Real World Example: Test jig for METOP spacecraftRaw AP203 export in ESARAD

    STEP for Aerospace Workshop - NASA-JPL


    Real world example test jig for metop spacecraft final jig model positioned on spacecraft

    After adaptation in ESARAD modeller and adding thermal features

    Estimated 25% reduction in model construction effort

    So, even without NURB support already significant savings

    Real World Example: Test jig for METOP spacecraftFinal jig model positioned on spacecraft

    STEP for Aerospace Workshop - NASA-JPL


    Ray tracing with nurb surfaces
    Ray-tracing with NURB surfaces features

    • Status:

      • Algorithm works functionally

      • First round of performance tuning done

      • Just before workshop delivered to ESA for acceptance testing

    • Functionality will be incorporated in next industrial release of ESARAD

    STEP for Aerospace Workshop - NASA-JPL


    Example nurb shapes now supported in esarad ray tracing
    Example NURB shapes now supported featuresin ESARAD ray-tracing

    Some X-38-like concept -- no status -- just a test model

    STEP for Aerospace Workshop - NASA-JPL


    Conclusions
    Conclusions features

    • Import from CAD to ESARAD is working well

      • Could not have been done sensibly without STEP

      • Very promising development

  • Emphasis is on improving the engineering analysis cycle

    • NURB support in ESARAD is for most cases not really needed from the thermal analysis point of view

    • Striving to increase the efficiency and effectivity of the engineer, not optimising on CPU or other computer resource usage

  • However, high-fidelity NURB surfaces can be appropriate in some special cases thermal or thermal/optical analysis

    • Mirror optics

    • Parasitic heatloads infra-red sensors, passive cooler baffles

  • STEP for Aerospace Workshop - NASA-JPL


    Future
    Future features

    • Complete testing

    • Testing with exports from other CAD packages - enhancement of heuristic shape recognition

    • Improve transfer of product and part info (meta data)

    • AP203 to STEP-TAS converter?

    • AP203 import and NURB ray-tracing in next major industrial release of ESARAD

    STEP for Aerospace Workshop - NASA-JPL


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