MSC Russia VPD Conference | November 16-17 2005 |
Virtual Product Development for the Helicopter IndustryPeter MikolajDirector Technical Team Automotive / Aerospace Europe
November 2005
MSC Russia VPD Conference | November 16-17 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
MSC Russia VPD Conference | November 16-17 2005 |
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
MSC Russia VPD Conference | November 16-17 2005 |
Main Rotor Hub• Using data from multiple codes• Modelling mechanical systems, flexible systems and
control laws
MSC Russia VPD Conference | November 16-17 2005 |
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
MSC Russia VPD Conference | November 16-17 2005 |
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
MSC Russia VPD Conference | November 16-17 2005 |
Standard Approach for Fatigue
LoadsMultibodyDynamic
MultibodyDynamic
ExternalInputs
Optimization
Fatigue Life
FatigueMethodology
FatigueMethodology
MaterialData
Linear Superposition
StressesFEModelFE
Model
MSC Russia VPD Conference | November 16-17 2005 |
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
MSC Russia VPD Conference | November 16-17 2005 |
Life Prediction – Loads & Geometry
• Loads & Stresses (from MSC.ADAMS)• Modal coordinate time
histories• 42 modes (0-1000Hz)• Modal stresses
MSC Russia VPD Conference | November 16-17 2005 |
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
MSC Russia VPD Conference | November 16-17 2005 |
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
MSC Russia VPD Conference | November 16-17 2005 |
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
MSC Russia VPD Conference | November 16-17 2005 |
Sizing Results• DV’s normalised to one• No discrete variables
• DV’s normalised to num plies
• Constrained to whole num. plies
MSC Russia VPD Conference | November 16-17 2005 |
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
MSC Russia VPD Conference | November 16-17 2005 |
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
MSC Russia VPD Conference | November 16-17 2005 |
Single Landing Gear Drop Testing Analysis
Helicopter Crash Assessment Process
MSC Russia VPD Conference | November 16-17 2005 |
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 Russia VPD Conference | November 16-17 2005 |
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 Russia VPD Conference | November 16-17 2005 |
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.
MSC Russia VPD Conference | November 16-17 2005 |
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
MSC Russia VPD Conference | November 16-17 2005 |
Rotorblade Delamination
• Delamination FailureCritieria
• Longitudinal normal shear • Modified distortion energy • Relative rotation criteria• Fiber strain limit• Strain invariant failure
theory• Custom criteria
MSC Russia VPD Conference | November 16-17 2005 |
Blade and material DescriptionNumber of Elements: 15771Number of Nodes: 21829Material : 1) Aluminum 7050, 2) compositeBoundary Condition: All the bottom nodes are fixed.
Rotorblade Delamination
MSC Russia VPD Conference | November 16-17 2005 |
Blade Deflection at Peak of Cyclic Loading
Range = -0.26 – 0.035 inch
MSC Russia VPD Conference | November 16-17 2005 |
Delaminated Damage at the end of cyclic loading
Relative Rotation Criterion
Delaminated Damage Area Blade Natural frequency of vs. fatigue cycle
MSC Russia VPD Conference | November 16-17 2005 |
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)
MSC Russia VPD Conference | November 16-17 2005 |
Fractured node at the blade stemFractured Area, Failure
Mechanisms ContributionInspection Intervals/Damage
Energy Release Rate (in-lbs/in2) Vs. Cycles
Show Fractured Nodes
MSC Russia VPD Conference | November 16-17 2005 |
Landing Gear FE Model
Composite Main Landing Gear Damage Detection
Generalize Stress (Nx)
Damage location,ContributingFailure Mechanisms
Composite Landing Gear
Relative Rotation(Delamination)
MSC Russia VPD Conference | November 16-17 2005 |
•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