Reliability Testing Tools and Methods for Wind Turbine Drive Trains

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Reliability Testing Tools and Methods for Wind
Turbine Drive Trains
Robert Orange, Systems Engineer MTS Systems
Corporation

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MTS Mechanical Test Simulation Solution
Supplier

• Ground Vehicles
• Aero Structures
• Materials Structures
• Includes Wind Applications
• Sensors

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Presentation Outline

• Review the Mechanical Testing Rationale
  Requirements
• Highlight Some Characteristics of Reliability
  Testing
• Review Aero Structural Ground Vehicle Testing
• Introduce Additional Test Methods

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Reliability Review - Loads vs. Susceptibility
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Development Testing
Loads Definition
Subsystem Testing
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Test Types

• HALT (Highly Accelerated Life Test)
• Robustness test to identify weak points in the
  design
• ALT (Accelerated Life Test)
• Get reliability (failure rate) information
• Others
• Loads Definition Tests, etc.
• Acceleration Methods
• Time Compression Load Amplification

Loads gtgt Service
Loads ? Max Service
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Summary Reliability Tests

• Know both
• Service loading (at critical component level)
• and
• Component strength (know failure modes)
• Can use testing for many purposes
• Make sure the test rig / test plan meets the
  requirement.
• Test Acceleration is necessary but dangerous

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Aerospace Structures

• Flight Envelope Defines Static Limits
• Service Life Flight Envelope is basis for
  fatigue testing
• Tests
• Massively multi-axial
• Go from one balanced state to another balanced
  state
• Acceleration Methods
• Time Compression
• Load Amplification (choosing edges of flight
  envelope)

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Ground Vehicles

• Use Time Histories (rough road data)
• Multi-Axial Dynamic
• Testing at system, sub-system and component
  levels
• Loads definitions flow down from initial road
  load data tests on model and/or proxy test
  article
• System reliability built up from components,
  final tests at system level
• Acceleration Methods
• Time compression (fatigue based editing)
• Load Amplification (start from rough road
  conditions on full vehicle)

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Common Characteristics Aero/Ground Vehicles

• Rationale for loading starts from external
  environment
• Used at all levels of development (V diagram)
• Loads definitions Component Testing
  Integration Testing
• Tests
• All loads of significance are present in the test
• Load relationships match service conditions
• Load Amplification is at the limit of expected
  service loads

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Tools/Methods

• Time Compression
• Load Replication
• RPC (Remote Parameter Control)
• Hybrid Simulation

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Fatigue-based Editing
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Load Replication RPC

• Remote Parameter Control
• Method to reproduce
• Parameters loads/strains/accelerations/displacem
  ents
• At remote location Gbx bearing races, Gbx
  Mounting, Main bearing
• Get high fidelity of loads at critical components
• Real or constructed (IEC DLC) demand waveforms

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RPC Iterations
Test Rig
Nacelle
Drive
Response

Response Error
FRF-1
Drive Correction
-
Desired Response
Continue until response error ? 0
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Load Replication - Hybrid Simulation

• Combination of math model, test rig and system
  under test
• For drive train test rig
• Input Transient Wind Field ( could come from
  IEC DLCs)
• Model Blades, Hub, Tower, Foundation, Pitch
  Yaw Response
• Real
• Nacelle with controller
• Test Rig

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Test Rig
Nacelle WTC Controller
Rig Commands
WTC Pitch Yaw Cmds
Hub Forces Moments
Wind
Anemometer
Blade Model
Pitch Yaw Models
11/18/2015
Page 16
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Hybrid Simulation

• Benefits
• Most accurate replication of events
• WTG controller strategies will effect response to
  transient wind and affect loads
• No iteration steps to converge on solution real
  time
• Costs
• Most sophisticated test setup
• Highest demand on the rig controller and
  mechanical system
• Accuracy dependent upon model fidelity

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Summary

• To Achieve Higher Reliability
• Need to link service loads to test loads
• Need to integrate testing into all phases of the
  design cycle
• Do more than HALT testing
• Consider using tools that are well developed in
  other industries
• Fatigue-based editing
• Remote Parameter Control (RPC)
• Hybrid Simulation

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Thank You!

• Photos courtesy of
• Cessna Aircraft Corporation
• University of Minnesota
• Airbus Military
• Fraunhofer Institute LBF