Moventas XL Life Extension Program

Moventas XL Life Extension Program

Wesley ThomasVice President, Major Accounts

Sentient Science Overview – Core Goals, IP, and Industries

A Trusted Third Party Enabling Life Extension of Rotating Equipment in two ways:1. Computational Testing & Demand Management for Suppliers 2. Asset Management for Operators

☑ Life Extension☑ Root Causes☑ Predict Earlier

Key Industries Served

WIND ENERGY • 200,000 Global units• 20,000 assets under contract

AEROSPACE• Rotorcraft, Fixed Wing, & Defense• (15 Years of R&D)

RAIL• Wheel Rail Interface• Top of the Rail Friction Modifier and

Lubricants

Sentient Science Current Approach to Gearbox/Bearing Modeling

• Physical tests are unavoidable, but also expensive

• Sentient offers it’s DigitalClone technology to provide a sophisticated virtual test Lab

• Virtual test labs can support physical tests• Reduce costs• Go into physical testing with more confidence

• DigitalClone can determine bearing and gear life based on:

• Bearing material (Hardness, inclusions, etc)• Surface finish (grinded, polished, superfinished,

etc.)• Lubrication properties (pressure and heat

dependent viscosity, etc.)

Moventas XL Life Extension Program - WindEurope 2017

© 2016 Sentient Science Corporation – Confidential & Proprietary

GE 1.5MW wind turbines have experienced premature failures in the field before expected L10 20 year life

Operators have experienced repeat failures of spare gearboxes that did not meet reliability expectations, and this has led to rising Major Component Repair and Replacement costs after end-of-warranty date.

Moventas saw an opportunity to improve the design and components of known failure modes to reduce future failures, reduce O&M cost, and improve availability

Moventas requested Sentient Science to provide third-party assessment of these key technology upgrades and quantify the life extension benefits for owner-operators

Why Moventas Developed GE 1.5MW Extra Life Gearbox?

Reduce Future Wind Turbine O&M costs and maintain high turbine availability



Moventas Extra Life Technology Upgrades:

1.1 Case carburized ring gear – Benchmark performance against industry standard to show the difference in component durability.

1.2 Integrated planet gear bearings - Prove that the 2-row arrangement is more robust than a 4-row arrangement, and benchmark the performance against a industry standard.

1.3 Improved tooth surface roughness – Prove that the surface roughness of Ra=0.3 will improve micropitting resistance compared with Ra=0.6.

1.4 Improved material specifications in geared components – Prove that new material specification is better than old one and provide benchmark analysis against industry standard

1.5 New material in bearings – Prove that White Etch resistant bearing is more resistant to white etching cracks than old design and industry standard.

IMS Pinion


DigitalClone Fatigue Life SimulationsProcedure, assumptions and technical details

Given:• GE 1.5 MW Turbine• Material samples provided by Moventas• Technical details on Moventas PLH-1100, PLH-1100-XL

gearbox improvements

Assumptions:• Material properties from Sentient’s Library as needed

Procedure:• Loading analysis • Mixed elastohydrodynamic lubrication analysis• Lifing calculations• Post processing and interpretation of results

• Sentient conducted in-detail material characterization analysis on Moventas provided bearing samples to obtain the following technical details, input to DigitalClone material and life prediction model

– Grain size and morphology

– Case microstructure, core microstructure, case-core transition region microstructure

– Defects, non-metallic inclusions size distribution, if any

– Material imperfections, retained austenite, grind burn etc.

– Residual stress analysis

– Surface roughness analysis


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Moventas GE 1.5 Extra Life Gearbox Upgrades - Summary

IntegratedPlanet GearBearing

CaseCarburized Ring Gear

New BearingMaterials for High Speed Stage

Improved ToothSurface RoughnessIn Gears

ImprovedGear MaterialSpecifications

=BRG 1

BRG 2

Black oxide layer+ White Etch Resistant

60.8 61.2 61.9 61.2 60.8

56.758.7

53.852 52.3

48.746.8 47

44.3

40.8 40.5

30

35

40

45

50

55

60

65

0 500 1000 1500 2000 2500 3000 3500

Ro

ckw

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: HR

C

Depth: Microns

0.5Kg

GE 1.5 Extra Life Gearbox Achieves 4x Life



Legacy Gearbox vs. Moventas PLH-1100 Critical Locations:

Legacy Gearbox Moventas PLH 1100.2

Critical Components

Normal Roller Load

(N)

ContactStress (GPa)

Normal Roller Load

(N)

ContactStress (GPa)

LSS_UW 30,887 1.470 37,433 1.264

LSS_DW 34,488 1.385 11,829 0.929

IMS_UW 15,969 0.965 14,451 1.074

IMS_DW 65,508 1.218 71,752 1.300

HSS_UW 29,961 1.174 33,225 1.167

HSS_DW 13,451 1.129 10,922 0.922

PGC 51,208 1.880 148,442 1.741

Highest StressLowest Stress

Input Power

Output Power

Planet Gear Bearing

and Planet Gear

Low Speed Bearing

Upwind

Intermediate Speed Shaft

Bearing Upwind

High Speed Shaft

Bearing Upwind

Planetary Carrier

Bearing Upwind

Planetary Carrier

Bearing Downwind

Low Speed Bearing

Downwind

Intermediate Speed Shaft

Bearing Downwind

High Speed Shaft

Bearing Downwind

Sun

Pinion

Low Speed

Shaft Gear

Intermediate

Speed Shaft

Pinion

High Speed

Shaft Pinion

Intermediate

Speed Shaft

Wheel

• Sentient modeled the differences in GE1.5 MW Moventas PLH 1100.2 and Legacy Gearbox gearboxes

• Overall, PLH-1100.2 bearings have relatively lower stresses than Legacy Gearbox

• Moventas PLH-1100.2 integrated planet gear bearing design results in lower stresses



Advanced Technology #1: New Bearing Materialsfor High Speed Shaft Bearings (HSS)

Black Oxide (BO)White Layer Etch Resistant



MnS + Oxide

MnS + Oxide

Component Hardness, HRC

Inner race 60

Outer race 61

Roller 61

Outer Race

Case Core

Case Core

• Non-metallic MnS, Oxide and TiN inclusions are observed in the inner and outer raceway as-large-as (ALA) 35 and 50 µm, respectively • Inner raceway consists of Bainitic microstructure whereas Outer race has good martensitic microstructure• Roller is relatively clean and have good tempered martensitic microstructure• Black oxide thickness varies from 0.8 µm to 1.5 µm

Inner Race

Black oxide layer

Advanced Technology #1: New Bearing Materials for HSS Bearing - BO



62 62 62 62 62 62

59

56

51

47 47 47 46 47 47

6062 62 62 62

61 61 61 61 61

40

45

50

55

60

65

0 500 1000 1500 2000 2500 3000 3500 4000 4500

Ro

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HR

C

Depth: Microns

White Etch Resistant Bearing

IR

OR

RLR

OxideCase Case

InnerRace

• IR is case hardened, whereas both OR and roller are through hardened.

• IR case hardness is 62 and core is 47 HRC.• Average roughness of OR and roller is 62 and 61

HRC, respectively.• Presence of globular oxides, MnS and TiN

inclusions ALA 10 µm were observed in Inner Race

• High Cr % of 2.99% in the matrix

Advanced Technology #1: New Bearing Materials for HSS Bearing – White Etch Resistant Bearing


• Sentient conducted total 1,000 contact fatigue life simulations at 1.6 MW nominal torque and speed to predict the dominant damage mode and life

- Pitting/spalling/wear• PLH 1100.2 XL HSS bearings have relatively lower contact stresses• White Etch Resistant and BO material quality is superior and have additional protection in the form of black oxide coating • DigitalClone predicts both White Etch Resistant and BO bearings to meet L10 life of 20 years. • However, BO predicted to have 3% probability of failure (POF) in less 20 years due to non-metallic inclusions. BO bearing

predicted to have relatively lower life under high torque/uprate conditions• White Etch Resistant is superior in protection against white etch cracking resulting from heat treatment and improved

microstructure• Sentient recommends to use White Etch Resistant bearing at HSS and HSIS bearing locations to avoid axial cracking

RVE Size: 2.45mm by 1.57 mmNo. of grains: 11,646

Bearing Contact surface

Advanced Technology #1: New Bearing MaterialsWhite Etch Resistant and BO HSS Bearings Fatigue Life Simulation Results & Recommendations

Bearing Type L10-Fatigue Life , years Contact stress, GPa

HSS_White Etch Resistant 20 1.2 (UW-side)

HSS_BO 20 1.2 (UW-side)



Advanced Technology #2: Integrated Planet Gear Bearings



Component Supplier A, HRC Supplier B, HRC

Races 61 60

Roller 61 60

MnS+Oxide

Case Core

Case Core

Supplier A

Supplier B

• Supplier A: Good hardness, Tempered martensitic microstructure with slight carbide banding and non-metallic inclusions as large as 10 µm

• Supplier B: Good hardness, Bainitic microstructure, slight carbide banding, and non-metallic inclusions as large as 30 µm

Advanced Technology #2: Integrated Planet Gear Bearings, 2-Row: Supplier A vs Supplier B

MnS+TiN+Oxide

Case Core



Advanced Technology #2: Legacy Planet Gear Bearings, 4-Row: Supplier A vs. Supplier B

Supplier B

Case Core

Inclusion

• Supplier A: Good hardness, tempered martensitic microstructure, carbide banding and non-metallic inclusions as large as 50 µm

• Supplier B: Good hardness, Bainitic microstructure and non-metallic inclusions as large as 50 µm

Case Core

Mulit-phase inclusionButterfly formation

Supplier A

Component Supplier A, HRC Supplier B, HRC

Races 63 61

Roller 62 61



Moventas GE 1.5 Extra Life Gearbox Achieves 4x Life

Legacy GBX –Supplier B

PLH-Supplier B

Legacy Gearbox –Supplier A

PLH-Supplier A

• Sentient conducted 2000 fatigue life simulations to compare PLH1100 planet

bearing with Legacy gearbox

• DigitalClone fatigue life simulations predicted:

• Highest fatigue life of PLH 1100 -XL-A bearing due to clean material

quality and relatively lower contact stress

• Fatigue life of PLH 1100 XL- B is higher than Legacy Gearbox due to

lower contact stress and better material quality

• Legacy gearbox planet shaft bearing fatigue lives are lower as they

experience higher contact stresses and have lower material quality

• The material quality difference between Bearing A MVS and Legacy is

more significant than Bearing B, hence the huge difference in life

Advanced Technology #2: Integrated Planet Gear BearingsPLH 1100 and Legacy Gearbox Bearing A&B Fatigue Life Simulation Results

Case Study

Max Contact Pressure

(MPa)

L10rev

L50rev

L90rev

Life Improvement

PLH 1100_XL – A 1741 2.67E+09 1.31E+11 1.57E+12 216x

PLH 1100_XL - B 1741 3.18E+08 5.60E+09 3.48E+10 26x

Legacy - A 1880 3.78E+07 8.36E+08 6.01E+09 4x

Legacy - B 1880 1.05E+07 1.35E+09 2.97E+10 1x Moventas XL Life Extension Program - WindEurope 2017


Advanced Technology #3: Case Carburized Ring Gear



Advanced Technology #3: Case Carburized Ring GearLegacy Gearbox Ring Gear Material Quality

59

49

3833 31 32 35 33 35 35 34 35 33 32 34

28 31 33 30 31

0

10

20

30

40

50

60

70

0 200 400 600 800 1000 1200 1400 1600 1800 2000

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HR

C

Depth: Microns

Ring Gear

Max Hardness: 59 HRC

Min Hardness: 28 HRC

• Ring gear is case carburized with max. surface hardness of 59 HRC and min. hardness of 28 HRC.

• Case depth is 100µm

• MnS, Tin and Oxide inclusions as large as 40 µm

• Ring gear is case hardened and contains intergranular Cracks, Nitrided layer on surface, Fe3N grain boundary networks in the microstructure. These abnormal microstructure features lead to early crack nucleation and premature failures

Contact surface

Indents

MnS inclusion

Tri-phase inclusions



Legacy Gearbox

Ring gear

Max Contact Pressure

Pmax(MPa)

L10, cyc

L50,cyc

L90, cyc

PLH-1100.2 137120 years life ( based on clean material quality and

no serial defects)

Legacy Gearbox 1371 1.60E+07 6.80E+08 7.42E+09

• Sentient conducted a total of 1000 contact and bending simulations to predict the effect of case carburization on fatigue life

• PLH 1100 XL ring gear have L10 fatigue life of 20 years based on assumption of clean material quality and no serial defects

• Legacy Gearbox ring gear with poor material quality predicted to have life less than 7 years of L10 fatigue life

Advanced Technology #3: Case Carburized Ring GearPLH 1100 XL and Legacy Gearbox– Ring Gear Fatigue Life Simulation Results & Recommendations



Advanced Technology #4: Improved Material Specifications in Geared Components



IMS pinion with inclusions

IMS pinionMax Contact

Pressure(MPa)

L10,cyc

L50, cyc

L90,cyc

With no inclusions 1330 20 years life ( based on clean material quality)

With inclusions 1330 5.64E+06 9.75E+08 2.60E+10

• Sentient conducted contact fatigue life simulations to study the impact of non-metallic inclusions on IMS pinion fatigue lfie• PLH 1100.2 IMS pinion with no presence of detrimental

inclusions is predicted to meet design L10 life of 20 years based on clean material quality and no serial defects

• PLH 1100.2 with detrimental inclusions (ALA 150 µ) predicted to have L10 fatigue life of less than 5 years

• It is recommended to use IMS pinion with martensitic

microstructure with non-metallic MnS inclusions of size

ALA <30µm and lower inclusion density for superior

fatigue life

Advanced Technology #4: Improved Material Specifications PLH 1100 IMS Pinion – Effect of Inclusions Fatigue Life Simulation Results & Recommendations



Advanced Technology #5: Improved Tooth Surface Roughness


Ra = 0.3

Ra = 0.01

Ra = 0.6

Sun Pinion with Ra, µm

Pmax(MPa)

L10, cyc L50, cyc L90, cyc Life Factor

0.01 1781 9.08E+06 5.24E+07 6.67E+08 2.9x

0.3 1781 6.89E+06 3.75E+07 2.51E+08 2.2x

0.6 1781 3.10E+06 2.45E+07 1.77E+08 1x

PLH 1100 XL –Sun Pinion Fatigue Life Simulations and Recommendations

• Sentient conducted RCF simulations to predict the effect of surface finish on Sun Pinion fatigue life

• Compared to Ra of 0.6 µm, Sun Pinion with 0.3 µm has a significant increase in L10 fatigue life (by a factor of 2.2x)

• Increase in RCF L10 life (factor of 2.9x) with superfinish(Ra: 0.01 µm)

• It is recommended to have Ra of 0.3 µm as a minimum surface finish specification

Mixed-EHL pressure profiles for progressively smoother surface roughness

Ra: 0.01µmRa: 0.2µmRa: 0.3µmRa: 0.6µm

Advanced Technology #5: Improved Tooth Surface Roughness


Summary of Findings• Sentient completed modeling and comparison of PLH 1100, XL and Legacy Gearbox performance considering

design, manufacturing, materials, and loading conditions.

• Overall, PLH-1100 bearings have relatively lower stresses than Legacy Gearbox

• PLH-1100 integrated planet gear bearing design results in 8% lower contact stresses

• XL gearbox predicted to meet design L10 life of 20 years due to overall improvements in using advanced bearings, case carburized ring gear, better surface finish and clean martensitic microstructure with no presence of detrimental inclusions

• Compared to Black Oxide (BO) bearing, White Etch Resistant bearing is superior in protection against white etch cracking resulting from heat treatment and improved microstructure

• XL gearbox improvements can be reused in Moventas future gearbox designs, rebuilds and uptower repair services


DigitalClone Recommendations1. Sentient recommends to use White etch resistant case carburized bearing with high Cr-content in XL gearbox HSS

and HSIS bearing locations

2. Black oxide and case carburized integrated planet gear bearings with retained austenite of 20-25% is recommended

3. For ring gear, case carburized martensitic microstructure with a case depth of about 1500 µm and case hardness of >60 HRC is recommended

4. The following microstructural features need to be avoided or reduced for better fatigue performance1. Needle-like non-metallic MnS and metallic TiN inclusions of size >30µm and higher inclusion density

2. Carbide banding

3. Oxide/intergranular oxidation sites

4. Grain coarsening and de-carburization layer

5. It is recommended to have Ra of 0.3 µm as a minimum surface finish specifications to reduce asperity interactions and increase in XL gears and pinions RCF life


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Moventas GE 1.5 Extra Life Gearbox Upgrades - Summary

IntegratedPlanet GearBearing

CaseCarburized Ring Gear

New BearingMaterials for High Speed Stage

Improved ToothSurface RoughnessIn Gears

ImprovedGear MaterialSpecifications

=BRG 1

BRG 2

Black oxide layer+ White Etch Resistant

60.8 61.2 61.9 61.2 60.8

56.758.7

53.852 52.3

48.746.8 47

44.3

40.8 40.5

30

35

40

45

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55

60

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0 500 1000 1500 2000 2500 3000 3500

Ro

ckw

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: HR

C

Depth: Microns

0.5Kg

GE 1.5 Extra Life Gearbox Achieves 4x Life


Thank you! Learn More and Meet the Team!

Sentient Presentation Schedule WindEurope 2017

1. Introducing DigitalClone Live

2. Duke Energy Case Study

3. Main Bearing RCA

4. How to Value Digitalization

5. DigitalClone Live Product Update

6. Why Data Science Alone Wont Lower the Cost of Energy

7. Moventas XL Life Extension Program

9. Rewitec Additives to Extend Gearbox Life

10. DigitalClone Bearing Product Release

11. Wind Loads Modeling

12. Data Fusion: Material Science & Data Science

13. Drivetrain Modeling

14. Reducing Costs with Digitalization


Moventas XL Life Extension Program

Engineering

Transcript of Moventas XL Life Extension Program