# Presentation: 290397

## TASverter and the UpgradedSTEP-NRF and STEP-TAS Protocols

- Hans Peter de Koning (ESA/ESTEC D/TOS-MCV, The Netherlands)
- Hans-Peter.de.Koning@esa.int
- 2003 NASA-ESA Workshop on Aerospace Product Data Exchange
- April 7-10, 2003, NIST, Gaithersburg, Md, USA

**Notes:**
<Simulog est une société fondée à l’initiative de l’INRIA (INSTITUT NATIONAL DE RECHERCHE EN INFORMATIQUE ET AUTOMATIQUE) il y a plus de 10 ans, en 1984.
La définition de la mission de l’entreprise  est basée sur l’objectif initial de ses initiateurs: être un pont entre l’industrie et la recherche publique.

La mission de l’entreprise comporte deux points qui reflètent notre stratégie mais aussi le marché sur lequel Simulog évolue:
L’objectif numéro 1 est de fournir une gamme de prestation complète: Simulog doit intégrer les solutions proposées dans l’environnement industriel préexistant de ses clients.
Cette connaissance approfondie des besoins du client , de son métier et de son environnement permet d’atteindre plusieurs objectifs positifs: 1. la mise en confiance du client, qui facilite le dialogue lors de la phase de spécification des besoins (meilleure compréhension des besoins) et lors de l’apport des solutions nouvelles (plus grande facilité à obtenir l’adhésion du client). 2. la fidélisation du client, qui permet d'accroître l’efficacité et la rentabilité des études au fur et à mesure.
L’objectif numéro 2 consiste à s’adapter aux nouvelles technologies pour offrir au client une solution industrielle à un problème ne pouvant être traité par les méthodes classiques.
>

## Topics

- Brief recap of STEP-NRF and STEP-TAS protocols
- Why TASverter ?
- Scope and purpose of  TASverter
- Development approach
- Updates to NRF and TAS protocols
- Current status
- Outlook

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003

## Recap STEP-NRF (1)(Network-model Results Format)

- Generic, discipline-independent exchange of models & results
- Model definition, using a discrete network representation
- Supports model/submodel hierarchy
- Results data, produced in analysis, test or operation
- Meta-data, which records details of actual analysis, test or operation performed
- Only discrete observations
- I.e. sampled results at discrete locations for discrete states of the model / object under observation, no support for continuous fields or similar
- Any property value has explicit (physical) quantity and unit
- Data model designed to cope efficiently with large amounts of results
- Built-in support for scalar, vector, matrix, tensor data

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003

## Recap STEP-NRF (2)(Network-model Results Format)

- Central NRF data structure is the ‘datacube’
- - each element of the cube is a scalar, vector or tensor property for a specific (item, quantity, state)
- - state quantity is normally time or frequence
- - ‘simple’ and ‘advanced’ SUBTYPEs, respectively for literal and generalised functional property values

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003

## Recap STEP-TAS(Thermal Analysis for Space)

- STEP-based application protocol
- Initial scope: Exchange of thermal-radiative models for space, including rigid body kinematics and orbit / attitude / orientation specification
- Geometry represented by bounded face model with minimal topology (compatible with AP 203 CC4)
- Extended scope: Exchange of thermal lumped parameter network models
- Targetting exchange between various SINDAs, ESATAN
- STEP-TAS is a pure superset of STEP-NRF (Used as ‘integrated resource’)
- Developed since 1996 mainly on ESA funding, supported by CNES, NASA
- Originally full ARM / AIM according to ISO TC184/SC4 procedures
- Accompagnying STEP-TAS library (C and F77 API) provided since 1998
- Many tools implemented prototype or industrial beta converters

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003

## Why TASverter ?

- STEP-TAS converters did not deliver industrial solution up to now
- Only ESARAD, THERMICA and Thermal Desktop have STEP-TAS exchange included in industrial releases
- Exchange is slow, often not reliable, and fails for large models
- Existing STEP-TAS architecture had too many layers
- Bad performance (CPU / elapsed time)
- Inefficient memory usage, huge memory requirements
- Expensive to verify and maintain
- Difficult to distribute on multiple platform/compiler combinations
- However principle of providing protocol + libraryis still very good and should be retained!

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003

## Scope and purpose of TASverter

- TASverter is an initiative of ESA/ESTEC D/TOS-MCV to:
- Offer users finally a properly working solution for exchange of thermal models
- First between major European analysis tools ESARAD and THERMICA
- Remove complicated dependency on (at least) 4 developers
- STEP-TAS and STEP library developers, Tool X and Tool Y developers
- Produce a fully functional (open source) framework for validation and verification of STEP-based data exchange protocols and implementations
- Lay a solid basis for the future
- Low threshold for implementation
- Maintainable and cost-effective
- Ensure long term availability (no third party dependence)

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003

## Development approach (1)

- Implementation in pure Python (v2.2)
- Following positive experience with earlier ‘ad-hoc’ converter developments
- Internal data storage uses STEP-TAS (ARM) data model
- Implemented in ‘STEP-TAS Repository Handler’, which is largely generated automatically with pyExpress from the STEP-TAS EXPRESS schema
- For each supported tool/format a ‘reader’ and a ‘writer’ is created
- Full testsuite built up alongside development
- Unit, integration and large model testcases under configuration control
- Integrated validation and fine-tuning of STEP-NRF and STEP-TAS
- Goal is recreation of models which are understandable and editable by humans
- Efficient update cycle is possible with pyExpress STEP-TAS library generator

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003

## Development approach (2)

*Phase 1*

- STEP-TAS Repository Handler
- (produced by pyExpress)

- thermica_VIF_reader

- thermica_SYSBAS_reader

- thermica_SYSBAS_writer

- esarad_erg_reader

- esarad_erg_writer

- THERMICA
- .SYSBAS

- THERMICA
- .VIF

- ESARAD
- .erg

- THERMICA
- SYSBAS-to-VIF-export

- Part_21_reader

- Part_21_writer

- STEP-TAS
- Part 21
- .stp

- TRASYS_reader

- TRASYS_writer

- TRASYS
- .inp

*temporary route via .VIF for quick development and verification *

- thermica_VIF_writer

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003

## Updates to NRF and TAS protocols (1)

- Removed AIM and mapping table, focussed on robust ARM
- Interoperability with AP203 was not achieved in practice
- Better do an executable AP203/TAS converter (retained mapping table for this)
- Cost of full AIM implementation, verification and maintenance too high
- Major clean-up and replacement of unclear terminology
- Resolved many issues collected over the years
- Includes artificial constructs in ARM from original AIM/GR mapping
- Changed TAS navigational structure from bottom-up to top-down
- Much easier / more natural to use in OO repository API
- Revalidated relationships for TAS geometry, meshing, thermal-radiative faces and made data model more consistent

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003

## Updates to NRF and TAS protocols (2)

- Updated NRF definitions for ‘datacube’, quantities and properties
- Permitted all permutations of ordering (item, quantity, state)
- Added a dedicated datacube for material properties
- Started to move protocol documents from MS Word to XHTML
- Revalidated all WHERE and RULE constraints
- Made all INVERSE attribute definitions consistent
- Consequence is that new STEP-TAS (ARM) Part 21 files are not compatible with previous STEP-TAS (AIM) Part 21 files
- Not a serious problem since STEP-TAS was not yet really in industrial use
- Last chance for this kind of updates

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003

## Current TASverter status

- Started in October 2002; second release made per 26 March 2003
- Self-contained Windows executable (no need to install Python)
- Download from http://www.estec.esa.int/thermsoft
- THERMICA .VIF and .SYSBAS readers
- ESARAD .erg writer
- Configuration controlled testsuite with unit and large model testcases,including fully automated run scripts for verification and regression testing
- Being tested by industrial users in Europe
- Now under construction
- ESARAD .erg reader
- THERMICA .VIF and .SYSBAS writers
- Upgrade Part 21 reader/writer to industrial level (pyExpress)

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003

## TASverter example 1: ISS_coldTHERMICA to ESARAD

- 711 thermal-radiative surfaces, converted in less than 15 seconds.

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003

## TASverter example 2: ATVTHERMICA to ESARAD

- 1700 thermal-radiative surfaces, converted in less than 25 seconds.
- Model hierarchy and coordinate transformations fully retained.

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003

## TASverter example 2: ATVTHERMICA to ESARAD

- Original THERMICA .SYSBAS

- Generated ESARAD .erg

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003

## Outlook (short term)

- Update STEP-NRF and STEP-TAS protocols (ARM only)
- Submit as NWI to ISO TC 184 / SC 4 for ballot as PAS or TS
- Provide and verify pyExpress generated C++ libraries for STEP-TAS
- Publish tools and schemas in open source
- pyExpress and TASverter
- STEP-TAS and STEP-NRF schemas, Python and C++ libraries
- ESA development STEP-SPE (Space Environmental Analysis)
- Currently open for tender, start foreseen summer 2003
- Extends TAS for micro-meteorites/debris, contamination, atomox, radiation ...
- Promote implementation STEP-TAS in other European and US tools
- Cigale2 (Alcatel), TMG, TSS, Thermal Desktop, ...

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003

## Outlook (longer term)

- Extend TASverter with new reader/writer plug-ins
- Transform existing TRASYS/ESARAD converter to TRASYS reader/writer
- Transform existing SINDA85/ESATAN converter to SINDA85 reader and ESATAN writer
- Add more SINDA/ESATAN-like readers / writers
- Add AP203 reader/writer, with primitive shape recognition capability
- Can be derived from existing AP203/ESARAD converter plus old TAS AIM mapping; possibly add facetting of remaining NURBS surfaces
- Construct HDF5 mapping and libraries for STEP-NRF
- Extend pyExpress to generate pure Fortran libraries
- Some demand for legacy applications (perhaps also SINDA / ESATAN)

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003

## Acknowledgements

- Co-workers at ESA/ESTEC: Simon Appel, David Alsina
- Contractor Simulog (France): Olivier Pailles, Arnaud Klinger
- Subcontractor GRAITEC (France): Eric Lebègue and co-workers
- ESARAD / ALSTOM Power (UK): Julian Thomas, David Scurrah
- THERMICA / Astrium SAS (France): Marc Jacquiau

- 2003 NASA-ESA Workshop on Aerospace PDE at NIST

- 7-10 April 2003