Virtual Product Development for the Helicopter Industrymscsoftware.ru/document/conf/Moscow_conf/conf_2005/Helicopter... · MSC Russia VPD Conference ... Virtual Product Development

MSC Russia VPD Conference | November 16-17 2005 |

Virtual Product Development for the Helicopter IndustryPeter MikolajDirector Technical Team Automotive / Aerospace Europe

November 2005


Imperative Needs in Helicopter Industry

• Products need to be easier to develop and cheaper to use as well as inherently more reliable

• Long product life cycles dictate regular technology insertions• Highly competitive market both on cost and capability grounds• Need for world class CAE to sustain and enhance market

position• Active vibration control systems to minimise component damage

and crew fatigue• Smart systems on rotors offering more freedom to simultaneously

improve performance and control vibratory forcing• Simulation needs to be done as early as possible to maximise the

benefits• Simulation demands that the modelling philosophy is sound -

achieved via correlation with test• Data integrity by tight integration between software tools


Functional Digital Aircraft®

Full Aircraft

Airframe Engines Landing Gear Cargo/Stores

Airframe

Aerodynamics

Control Surfaces

Cockpit

Simple/Complex

Bearings/Seals

Prop/Comp/Turb

Shafts

NLG & MLG

Tires

Brakes

Steering

Passengers

Cargo

Fuel Tanks

Weapons

Atmosphere

Pilot

Test Rigs

Controls Hydraulics Flexibility Electronics

Dynamics Vibrations Durability Design-of-Experiments

Runway


Main Rotor Hub• Using data from multiple codes• Modelling mechanical systems, flexible systems and

control laws


Rotor-Blade DesignBlade Structural Design methods • based on Finite Element (MSC.Patran,

MSC.Nastran) and 3D design

Blade Aerodynamics Design methods • based on CFD

- commercial software- CFD-Structure Coupling


Fatigue Problems

Crack

• Assess the durability of helicopter landing gear using CAE

• Include dynamic response of landing gear• Validate material• Validate design

• Target life = 12,000 missions


Standard Approach for Fatigue

LoadsMultibodyDynamic

MultibodyDynamic

ExternalInputs

Optimization

Fatigue Life

FatigueMethodology

FatigueMethodology

MaterialData

Linear Superposition

StressesFEModelFE

Model


Loads Generation – FE Model

• MSC.ADAMS model with flexible bodies and aerodynamic forces

• Controllers were developed for various events

• Load prediction on main gear

• Geometry for flexible bodies

• 21,861 CQUAD4


Life Prediction – Loads & Geometry

• Loads & Stresses (from MSC.ADAMS)• Modal coordinate time

histories• 42 modes (0-1000Hz)• Modal stresses


Life Prediction – Mission Profile

• Material• 826M31 (σy =800MPa, UTS=1200MPa)

• 300M (σy =1500MPa, UTS=1900MPa)

• Strain-Life Analysis• Neuber correction• Smith-Watson-Topper correction

• Duty Cycle Analysis• 1 Mission =

Take off + Landing • Run as single

fatigue analysis


Life Prediction - Results

• Fatigue Results Summary

28500

27605

3148

Life (missions)Node 12453

38300826M3112mmCase3

3207300M8mmCase2

<1826M318mmCase1

Life (missions)Node 979

MaterialWall thickness

Node 979

Node 12453

Target Life = 12,000 missions

Target Life = 12,000 missions


Optimizing Helicopter Composite Fairing

Zone PCOMP Total Ply Core -45° 0° 45° 90° TotalA 1 14.5 1.8 12.7 2 3 2 2 9B 1 14.5 1.8 12.7 2 3 2 2 9C 2 3.8 3.8 - 4 6 4 5 19D 3 2.2 2.2 - 2 4 2 3 11E 4 3.0 3.0 - 3 5 3 4 15F 5 14.5 1.8 12.7 2 3 2 2 9

Thickness (mm) Ply Count

Subcase Result Original Value Required ValueNormal Modes Lowest Frequency 52 Hz 60 HzSide Pressure Lateral Displacement 6.1 mm 5 mmTop Point Load Vertical Displacement 19.4 mm 15 mm

• Modify the laminate to achieve the required mechanical performance with the lowest increase in mass


Sizing Results• DV’s normalised to one• No discrete variables

• DV’s normalised to num plies

• Constrained to whole num. plies


Optimization Summary

• Optimization allows multiple multidisciplinary constraints

• Sizing yields updated properties• Property boundaries identified and

exported• Zones defined in CAD and transferred

back

TARGET LAYUP25/50/25

TARGET LAYUP40/40/20

• ZONE6

• ZONE4

• ZONE5

• ZONE1

• ZONE8

• ZONE2

• ZONE3

• ZONE10 • ZONE11• ZONE7

• ZONE9• ZONE12

Analysis (CAE)

Design (CAD)

Aero. Shape Zone Layup Ply Layup Ply Details Certification Manufacture


Helicopter Crash Assessment Process

1. Define multibody model in ADAMS to include tire, strut

2. Define fuselage mesh in Dytran3. Run simulations for water or land based

crash landing


Single Landing Gear Drop Testing Analysis

Helicopter Crash Assessment Process


PITCH CONTROL RODSCISSORS

ASSY

SPIDER

SLIDERBLADE

DAMPER

MASTEXTENSION ROD

MSC.Adams / MSC.NastranMSC.Adams / MSC.NastranChallenge:Tail rotor dynamic loadsSolution: ADAMS model with

imported CAMRAD aerodynamics and NASTRAN flexibility

Value: Understanding dynamic loads to use in design “ADAMS simulation therefore has permitted us to get different loading conditions for the half scissors to be studied through an FE analysis,puttinginto evidence the most critical loading combinations.”-- Bianchi F.Agusta Sp.a.


MSC.AdamsMSC.AdamsChallenge: Integrated product

development processSolution: Extensive evaluation led to

chosing MSC.ADAMS toolsValue: Anticipate one-third

reduction in project time“The capabilities of ADAMS will facilitate development of an integrated CAD/CAE application architecture which will lend itself to significant product development process improvement, including an expected one-third reduction in project time.”-- David G. EllisPrincipal Engineer


MSC.DytranMSC.Dytran

Challenge:Simulate impact on composite structureSolution: Eurocopter Germany is using MSC.Dytran to crash worthiness behavior of helicopter composite Value: Many crucial modifications have been applied leading to new fuselage concept, increase occupant safety while reducing tremendously the amount of physical tests.


Composite Fracture in Helicopter Design• Alphastar GENOA provides accurate life and

durability predictions for composite and metallic structures

• Utilizes full hierarchical modeling down to micro-scale• Employs micro-stress theory to account for

• Fiber and matrix damage• Delaminations• Manufacturing flaws, residual stresses and voids• Fiber buckling and waviness• Moisture and temperature

• GENOA FEA can be employed to reduce testing


Rotorblade Delamination

• Delamination FailureCritieria

• Longitudinal normal shear • Modified distortion energy • Relative rotation criteria• Fiber strain limit• Strain invariant failure

theory• Custom criteria


Blade and material DescriptionNumber of Elements: 15771Number of Nodes: 21829Material : 1) Aluminum 7050, 2) compositeBoundary Condition: All the bottom nodes are fixed.

Rotorblade Delamination


Blade Deflection at Peak of Cyclic Loading

Range = -0.26 – 0.035 inch


Delaminated Damage at the end of cyclic loading

Relative Rotation Criterion

Delaminated Damage Area Blade Natural frequency of vs. fatigue cycle


Damage Progression due to Excessive Delamination (Relative Rotation)

Bottom 3 plies (-45,45,0)

Bottom Middle 3 plies (-45,45,0) Top Middle 3 plies (-45,45,0)

Top Upper 3 plies (-45,45,0)


Fractured node at the blade stemFractured Area, Failure

Mechanisms ContributionInspection Intervals/Damage

Energy Release Rate (in-lbs/in2) Vs. Cycles

Show Fractured Nodes


Landing Gear FE Model

Composite Main Landing Gear Damage Detection

Generalize Stress (Nx)

Damage location,ContributingFailure Mechanisms

Composite Landing Gear

Relative Rotation(Delamination)


•Traditional methods are costly, slow and risky•Simulation reduces development time, reducing costs and improving quality

•Simulation can result in much closer co-operation between disciplines

•Next generation tools need to be an order of magnitude more sophisticated again

Conclusions

Documents

Virtual Product Development for the Helicopter Industrymscsoftware.ru/document/conf/Moscow_conf/conf_2005/Helicopter... · MSC Russia VPD Conference ... Virtual Product Development