Structural In-Service Monitoring of Advanced Combat

14年 5月 29日DGQT 95/

IDENTIFICATION DOC. INDICE DATE

1

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TITRE DE LA PRESENTATION

Advanced Combat Aircraft HUMS Division DÉFENSE 1

HUMS 2001

Structural In-Service Monitoringof Advanced Combat Aircraft:

Operational Benefits

X. Labourdette,Dassault Aviation,

Military Customer Support Division,78, quai Marcel Dassault,

Cedex 300, 92552 Saint-Cloud Cedex,France


HUMS 2001 CONTENTS

• Simple facts

• Structural Design Methodology

• The Rafale Health and Usage Monitoring System

• Operational Benefits

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HUMS 2001

• Simple facts





HUMS 2001

Emergence of the need for more advanced systemsEmergence of the need for more advanced systems

SIMPLE FACTS

• Structural monitoring of previous generation aircraft

dedicated

computer

strain

gauges

mass, power, reliability penaltypoor ageing, drift, re-calibration

+

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HUMS 2001

• Simple facts





HUMS 2001

Initial Conditions Aerodynamic LoadsFatigue Spectrum

Continuous Follow-up of all Dassault Aircraft Programs

Final DesignStructure Limit Loads

First Inspection & Maintenance Program

Initial Design LoadsDurability & Damage Tolerance

Development Components TestsAirframe Cell TestPrototype Flights

Inspection & MaintenanceProgram Updating

Fatigue Index Extension

Operational Flights Structure Limit Loads

Fatigue Test on Aged Aircraftfrom Fleet + Operational Loads

STRUCTURAL DESIGN METHODOLOGY

GENERAL

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HUMS 2001

Flight Tests on

Instrumented A/C

General

F.E.M.

LoadsCalibration

StructureLimitations

models calibration

and updating

BoundaryConditions / Loads

LoadsUpdating

Detailed

F.E.M.

AllowableCriteria

Validation

Documents

Aerodynamic

Base

Ground Tests

Partial & General

Flight ControlSystem


GENERAL VALIDATION PROCESS


HUMS 2001

Fzcanard

FzFrame 1

Fzmain gear

Fzarrester hookattachment

FFUS3

-400

-200

200

400

600

800

-400 -200 0 200 400 600 800

FU02FU01

prev

CA02

V006

FVLD3

-200

0

200

400

600

800

-200 0 200 400 600 800

VO11

VO12

VO09VO10

prev

Fuselage gauge Wing gauge

FE responses

CA01 :calibration

load

measures measures

FE responses

Measurement / Calculation Correlation: these ratio are injected in general FEM model


ON-GROUND CALIBRATION OF GAUGES

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HUMS 2001

Fuselage Stringer gauge( slope of My versus nz )

0

0.2

0.4

0.6

0.8

1

1.2

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8

Mach

+ 5 %

- 5 %

0

0.2

0.4

0.6

0.8

1

1.2

0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8

Wing Root gauge( slope of Mx versus nz )

Mach

+ 5 %

- 5 %

Samples of Flight/Computation Comparisons

Winggauge

-1000

0

1000

2000

3000

4000

5000

1 s

t

Roll manoeuvre : strain response in time


FLIGHT TEST EXPLOITATION

++

If ratio “max measured/max. computed” is not # 1then aeroelasticity database is re-calibrated by

modifying aerodynamic database


HUMS 2001

• Lifting surfaces grids

• Boxes (fuselage andexternal stores)

General FE model withreference loads

Manoeuvreconditions

Aeroelasticcomputation


FLIGHT LOADS CONSTRUCTION

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HUMS 2001

Certification

Calibrated F.E. Model

with Reference Loads

Detail

Models

Specific

Analyses

Tests

Procedures

Criteria

Allowables

Direct Exploitation

Wing Box Attachment


STATIC AND FATIGUE VALIDATION PROCESS


HUMS 2001

Mass Distributions (structural & non structural)

Internal Monitoring Quantities

(strain gauges / structural resistance indicators)

Creation with CATIA (geometrical & material characteristics)

Clean A/C Configuration


GENERAL FINITE ELEMENT MODEL

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HUMS 2001

Arresting hook lug (3D)Elementary specimen (2.5D)

Fitting

Type of Models especially used for Fatigue Calculations


AIRFAME VALIDATION : DETAILED MODELS EXPLOITATION


HUMS 2001

Composite materials

Aluminium alloys

Titanium (SPF / SPF-DB)

Miscellaneous


RAFALE MATERIALS

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HUMS 2001

COMPONENTS & A/C

SUB-COMPONENTS

DETAILS

ELEMENTS

COUPONS

specificspecimens

genericspecimens

database

structurefeatures


TEST PYRAMID LOGIC (STATIC AND FATIGUE)


HUMS 2001

Fastenerhole area

Large cut-out

Impact Bolted joints

Examples of Composite Coupons


COUPON TESTS

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HUMS 2001

Used for Design Criteria & Allowable Construction

Bolted Joint Stiffeners(Composite)


GENERIC ELEMENTS TESTS

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HUMS 2001

Full Scale Test :

Fatigue (25 000 hours)

Static : Limit Load x 2


AIRCRAFT COMPONENT TESTING


HUMS 2001

• Airframe in development definition

• 110 load introductions

• 3 000 gages

• 50 displacement sensors


MECHANICAL TEST AIRFRAME

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HUMS 2001 STRUCTURAL DESIGN METHODOLOGY

EXTERNAL STORES VALIDATION


HUMS 2001

Air to Air

Air to Ground(Heavy)

P (°/s)

0 nz (g)

LOAD FACTOR

Roll rate

Design Envelope


EXTERNAL STORES VALIDATION

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HUMS 2001

Number of Exceedanceper 1 000 Flight Hours

Nz

(g) STATIC DESIGN

STATIC DESIGN


FATIGUE REFERENCE SPECTRUM


HUMS 2001

N criticalN current

ActualPropagation

Curve

Structure Fatigue Strength calculated with Reference Spectrum

Fatigue Validation Fatigue or Propagation Index > 100

Flight Number (N)

crack size Propagation CurveReference Spectrum

Reference Spectrum : XX Flight Hours equivalent to Indexes = 100

In-Service Spectrum : Computation of F.I. & P.I. Actual Consumption


FATIGUE & PROPAGATION INDEXES

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HUMS 2001

Local Stress Intensity FactorLocal Fatigue Parameters

Geometry ParametersComputation

Material Data Base

Safe Life

Crack Length

Flight

Number

2024 Wöhler Curve

0

50

100

150

200

250

300

350

400

1 e+3 1 e+4 1 e+5 1 e +6

Number of cycles N

sig

ma

(MP

a)

-2

-1

0

1

2

3

4

5

6

7

8

9

Nz

100

101

102

103

104

-

- 2

- 1

0

1

2

3

4

5

6

7

8

9

1 0

1 1

1 2

RAINFLOW

Fatigue Index Propagation IndexFatigue Validation Documents


FATIGUE VALIDATION : COMPUTATION PROCESS


HUMS 2001

• Simple facts




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HUMS 2001 RAFALE HUMS

BASIC OPERATING PRINCIPLE

formattedcartridge

Pre-flightinspection

Shut down Post-flightinspection

Start up Flight

record initialization(tail number, date, time...)

maintenance datarecording

end ofrecording

A/C Mission Computer :

HUMSIn-flight

recorded data



CONCEPT - 1/3

Missioncomputer

• Local stress and fatigue depend on steering parameters

Monitors in real time peak-to-peak

values of steering parameters

Records steering parameters when

instantaneous peak-to-peak

exceeds pre-determined values

• All data are stored on a Mass Memory Cartridge

Detects and records static

exceedance on critical areas

(static operator database)

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CONCEPT - 2/3

GroundSupportStation

Reads and checks

data consistency

Computes local stress value on

each monitored area with tables

partial derivative tables

Determines peak-to-peak

value of local stress

Exploit static

exceedance on

critical areas

Performs Rainflow

counting

Sums up unitary index on

all peak-to-peak classes

(cumulative Miner law)

FI for last flight

Computes (PREFACE

model from ONERA)

threshold effect

PI for last flight


HUMS 2001

MassMemory

Cartridge

A/C Ageing metercomputation

Flight Fault Reportexploitation

MaintenanceManagement

System

Workprogram

Preventivemaintenance

operationCorrective

maintenanceoperation

Engine Ageing metercomputation

Structural fatiguecomputation

INU performancedisplay

Engine fileexploitation

Flight Fault Report:statistical analysis

Ground Support Station

RAFALE HUMS

CONCEPT - OTHER FUNCTIONS 3/3

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TYPICAL MAN-MACHINE INTERFACE


HUMS 2001

• Simple facts




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OPERATIONAL BENEFITS - 1/3

• On-ground computation of indexes enable to:

re-compute at any time the structural health of any area,

in combination an accurate F.E. modelisation,

very easily support the software, since it is not flight-rated

save computing power on-board of the aircraft

monitor a high number of areas (# 30 on Rafale), thus

providing for an itemised following of structurally

significant elements




• On-board monitoring of a limited set of non-dedicated steering

parameters enable to:

save computing power on-board of the aircraft

devote this function to the mission computer only

save the mass, power, volume and reliability penalties

generated by a dedicated system

record a high number of flights in the memory cartridge (10)

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• Accurate modelisation enables to plan structural maintenance

out of the actual use of the aircraft

• Fully automatic processing and clear language reduces training

needs for structural life consumption assessment

• Simple inspection procedures associated with this index

concept enable to support structural inspection at Intermediate

Level throughout the aircraft life.