reliability testing tools and methods for wind turbine drive trains

Reliability Testing Tools and Methods for Wind Turbine Drive Trains

Robert Orange, Systems Engineer

MTS Systems Corporation

04/19/2023

MTS: Mechanical Test & Simulation Solution Supplier

» Ground Vehicles» Aero Structures» Materials & Structures

– Includes Wind Applications

» Sensors

04/19/2023

Presentation Outline

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

04/19/2023

Reliability Review - Loads vs. Susceptibility

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Development & Testing

Conceptual Design

Sub-System Specifications

Component Specifications

System Validation

Sub-System Validation

Component Validation

Component DesignLoadsDefinition 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 >> 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

04/19/2023

Fatigue-based Editing

Edit time history data basedon regions selected from thedamage time history

Damage time historyshows where damagingcycles occur in the data

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Load Replication – RPC

» Remote Parameter Control– Method to reproduce:

» Parameters: loads/strains/accelerations/displacements» 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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Test RigNacelle

+

RPC Iterations

Continue until response error 0

Drive

Response

Desired Response

Response ErrorFRF-1Drive

Correction -

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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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Nacelle & WTC Controller

WTC Pitch & Yaw Cmds

Test Rig

Rig Commands

Pitch & Yaw Models

Blade Model

Wind AnemometerHub Forces & Moments

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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

04/19/2023

Thank You!

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

reliability testing tools and methods for wind turbine drive trains

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