3d functional tolerancing for helicopter rotor wp 1.5...– catia v5 caa integration – worst case...

Page: 1 September 20-21, 2005© 2004 VIVACE Consortium Members. All rights reserved

VIVACE FORUM 1 - WarwickHugo FALGARONE

Benoit FRICERO

3D functional 3D functional tolerancingtolerancingfor Helicopter Rotorfor Helicopter Rotor

WP 1.5.1WP 1.5.1

Introduction of tolerancing issues andstakes for tolerance management

Forum 1 – Warwick - September 20-21, 2005


VIVACE FORUM 1 - Warwick

Outlines

• Introduction

• Aerospace Tolerancing issues

• Tolerancing tools : State of the Art

• Comparison

• Methodology specifications

• Conclusions



Introduction

Tolerance analysis = Assembly simulation withmanufactured parts, ie parts with geometric variations.

Manufacturing capability requirement : Continous trade off between cheap manufacturingprocess and high quality product

Features relationship : Garantee Product functionsand assembly

How to define these tolerances ?

How to ensure tracability between function requirement and tolerance specification ?



Introduction

Functional tolerancing Vs Traditional dimensioning



Aerospace Tolerancing Issues

Manufacturing cost analysis for an aircraft structure :

Assembly

Manufacturing

Materials

55%

25%

20%

Improve product assemblability

Improve manufacturing capabilitiesImprove tolerance management methodologiesfrom design offices to manufacturing Quality.Use tools to support these methodologies




Technical data managed for tolerance analysis :

Design requirements: Aerodynamic,Weight, …• Product functions• Key characteristics• Assembly constraints

Product geometrical definition : Digital Mock Up

Manufacturing capabilities

Assembly sequence or kinematic model of assembly process

3D stack chain : List of contributing features for each requirement

Tolerance management is a multidisciplinary process




A

B

C

D

Nominal Model

A

B

C

Model with deviations

D

B

C

D

A

Sequence A->B->C->D

C

B

Sequence A->D->B ->C

A

D

Assembly sequence impact :

Tolerance annotations include implicitly assembly sequence

Sequence is chosen regarding to product main functions




Tolerance impact analysis :– How to understand specification for downstream

tolerance users : Manufacturing– How to impact design change on tolerance

specification ?

VIVACE use Case : Non conformityOne dimension of a manufacturd part is out of tolerance

How to status on the associated risk ?• Re-build tolerance analysis to find out

justification of tolerance specification.• Deal with non conformity process even without

Digital Mock Up ; Case of old programs still in production



Tolerancing tools State of the art

• Kinematic tolerancingObjective : Validate design concepts and define frontier tolerancesWhen : early design stageData needed : Rought geometry, Manufacturing capabilities, building philosophy (kinematic scheme)

• Feature tolerancingObjective : Validate assembly of toleranced parts When : Design validationData needed : Complete geometry with GD&T, assembly sequence

• Flexible tolerancingObjective : Simulate realistic assembly process When : Design validationData needed : FEM, DMU with GD&T, assembly sequence

• Tolerance editionObjective : Edit Geometrical Dimensional and Tolerancing annotations on DMUWhen : DMU Publication (drawings)

Different tools for different goals



Tolerancing tools : State of the art

• Kinematic tolerancingMecamaster Mecamaster SARLAnaTole EADS CCR

• Feature tolerancing3DCS DCSCeTOL6 Sigma SigMetrixTolerance Manager PCO TechnologieseMTolMate PCT

• Flexible tolerancingCATIA V5 – TAA Dassault Systemes

• Tolerance editionCATIA V5 – FTA & PFTA Dassault Systemes



Helicopter case study

Rotor case studyMast

Scissors

End Plate

Ring

Objective : Check the continous non-contact between thering and the end plate



Helicopter case study

• Nominal Position

Plane Contact

Ball JointMast

Scissors

End Plate

• Worst Case Position

Measure

Currently, this computation is done with simplified 1D stack chain.

Ring



Case study

Demo case study presentation

To simplify the demonstration, let’s use a demo case study easier to handle.

c

e

b

a

d

f

U1

U3 U2

Variations Measures




• Technical Description– Kinematic modelling with liaison– Catia V5 VB integration– Worst case & statistical computation– Variations are included in liaison

Mecamaster

• Remarks– Point based modeling ( no DMU necessary)– No dynamic link with DMU– No translation of Tolerance annotation– Statistical computation very limited– Well adapted for early tolerance analysis




• Modeling

Mecamaster

aa

b & d

f

e

c

Measures

Positioning link




• Technical Description– Kinematic modelling with liaison– Catia V5 CAA integration– Worst case & statistical computation– Variations are included in liaison

AnaTole

• Remarks– Point based modeling ( no DMU necessary)– No dynamic link with DMU– No translation of Tolerance annotation– Good over constraints systems analysis– Statistical computation – Well adapted for early tolerance analysis




• Modeling

Anatole

Measures

Positioning link




• Technical Description– Kinematic modelling with liaison– Assembly graph modelling– Catia V5 CAA integration– Worst case & statistical computation– Take into account of geometrical

tolerances

CeTol 6sigma

• Remarks– Friendly graphic user interface– Features based modeling ( DMU necessary)– over-constraints systems visualisation– lack of visualization of the model over the product




CeTol 6sigma

Measures

Positioning link

Tolerance

– This graph shows the degrees offreedom of each part and link

– It becomes hard to handle withcomplex assembly as rotor ofhelicopter




– Complex assemblies are not well managed by Cetol.

A complex assembly (CATProduct) is composed of assemblies (CATProduct) and parts (CATPart).

Each assembly of the product must NOT have over constraints issues in order to perform a Cetol study.

But this is often the case when designing an helicopter.

Product




• Technical Description– Modelling based on moves– Catia V5 CAA integration– Statistical computation only– Takes into account of

geometrical tolerances (FTA & PFTA)

3DCS

• Remarks– Point & Features based modeling( no DMU necessary)– Moves characteristics difficult to handle– Computation is only based on Monte Carlo algorithms

Movessequence




• Rotor modelisation

3DCS




Results

Stat

0.180.150.190.18Stat

0.250.310.310.29WC

U3

0.270.170.230.27Stat

0.360.390.420.39WC

U2

0.30.190.260.3

0.480.470.530.54WC

U1

CETOLANATOLEMECAMASTERCorrectResults

MEASURES

WC : Worst Case computationStat : Statistical computation



Comparison

Results differences come from :• Different computing algorithm• Different modeling approach

State of the art of tolerancing tools : • Tool evaluation. Computed results• Functions available regarding to user’s requirements• Modeling principle

Tolerance annotations are the result of an assembly model performed with a tool.

This model need to be managed with PLM.

This model need to be independent from the tool chosen



Methodology improvements

5.Impact analysis

1.Functionalanalysis

3. GeometricModeling

4.Tolerance analysis

FunctionsRequirements

Geometricalfunctionalskeleton

3D stack chain

Annotations

New tolerancing Methodology, based on new design parametric methodology

2. AssemblyModeling

GeometricalRequirementsKinematic schemeAssembly sequence

New method is necessary with a associated modeling. This model shouldn’t be dependent with the choosen tool.



Geometrical and functional Skeleton

Minimum geometry needed to perform functional tolerance analysis.





Structural and functional modelling

Assembly sequence modellingSystemic analysis of assembly Positioning datum choice

formalisationGeometrical variation propagation

representation – Datum Flow ChainGeometrical and Dimensional

Tolerancing management



Methodology specifications

Tool specifications :

As in 3DCS …Display 3d variation in order to validatemodeling

As in GAIA …Use schematic modeling for structural and functional analysis.

As in CeTol …Take into account Tolerance annotation

As in CeTol …Use assembly graphs

As in Anatole …Solve overconstraint system



Conclusions

• Tolerance analysis are performed by experts but it’s based on multidisciplinary models.

• Tolerance analysis is part of a product-process approach.

• Tolerance models should be available for all users oftoleranced drawings (design office, Manufacturing, Quality control, suppliers,…)

• Tolerance models shall be managed within the virtualProduct, and during all the lifecycle.



Questions ?

Thank you for your attention

[email protected]

3d functional tolerancing for helicopter rotor wp 1.5...– catia v5 caa integration – worst case...

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