Sept 06/IMechE

LOTAR and the Long Term Retention of Digital Models

Sean Barker, ARCS, CEng, MBCS, CITP

BAE SYSTEMS Advanced Technology Centre

© BAE SYSTEMS Aug 2006

Sept 06/IMechE

Effects of Generation Change

From PDES, LOTAR

Sept 06/IMechE

The Business Issue

Production

Start Design

CAD Obsolete

CAD Forgotten

Services

Legal Liability

Modifications

10 years 20 30 40 50 60

Spares

© BAE SYSTEMS Aug 2006

Sept 06/IMechE

LOTAR Focus by Objective

Retention of product models for Aerospace • Reuse

• Retain computer processable REPRESENTATION• CAD - e.g. redesign• PDM - e.g. configuration change• ...

• Certification and Legal Liability• Chain of Evidence

• Digital Signatures• Verification and Validation

Sept 06/IMechE

LOTAR Focus by Level

• Keep Hardware out of scope

• Keep Data OAIS Repository

• Keep Model LOTAR (EN

9300)

• Keep Knowledge KIM project

© BAE SYSTEMS Aug 2006

Sept 06/IMechE

A Drawing Records, A Model Defines

200mm 150mm

Drawings -

Dimensions define a drawing

Models -

Dimensions are read from a model

© BAE SYSTEMS Aug 2006

Sept 06/IMechE

Use Representation Knowledge

Presentation

A set of pixels

•20[W-];

•W25B100W-;

•98[W25BW98BW-];

• W25B100W-;

•-W;;

Knowledge

Squares:

• Have Symmetry

• Corners are stress concentrations

• Bad for manholes

Representation

Ordered set of Vertices

Assume algorithms for

• Boundaries

• Inside/outside

• Area

LOTAR

Sept 06/IMechE

LOTAR Focus by Objective

Retention of product models • Reuse

• Retain computer processable REPRESENTATION• CAD - e.g. redesign• PDM - e.g. configuration change• ...

• Certification and Legal Liability• Chain of Evidence

• Verification and Validation• Digital Signatures

Sept 06/IMechE

Model Verification

What Went In

Is What Came Out

ARCHIVE

Prove we have retained the master

From PDES, LOTAR

Sept 06/IMechE

Archive

Validation and Verification

DesignVerify Approve

Validate

Use

Retrieve

Show the model has not

changed

© BAE SYSTEMS Aug 2006

Validation

Properties

Sept 06/IMechE

• Smooth sampling point deviation calculation

• Sharp sampling point deviation calculation

Cloud of points - Smooth and Sharp Points

Shortest distance to imported surface

Native Model Target Model

Shortest distance to imported sharp edge

Smooth Edge

Sharp Edge

Native Model Target Model

Thanks to ITI, SNECMA

Sept 06/IMechE

Face Sampling Points Example #2

CADIQ Smooth Points CADIQ Sharp Points

Thanks to ITI & SNECMA

Sept 06/IMechE

Future

• More representations• Systems Engineering• Design Structure Matrices• ....

• Validation properties• PDM• ....

• Virtual schema databases