Improving Bearing Life and Performance

with Computational Testing

What Business Challenge Exists?

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

Conceptual Design

Detailed Design Prototype

Physical Testing Launch

Customer Tests Product in the FieldFailure

Could this perform better?

Unexpected Bearing Failures

Bearing Failure Causes System Redesign

- How do I change my bearing recommendation for customers?

- How can I quickly predict root cause and determine solutions?

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

Smart Testing for New Products

New Product Introduction

- How do I decrease go-to-

market time and cost for new

products?

- How do I maintain customer

confidence in the

performance of these new

products?

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

Perform More Testing in Budget

New Product Introduction

- How would design changes

to my current product lines

improve market share or

price premium?

- How can I market bearings

for each specific customer

application?

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

Highlight Competitive Advantage

Competitive Tool for

Performance

- How can I prove my bearing

enhancement to customers?

- How can I highlight my

bearing or enhancement’s

competitive advantage?

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

Fleet Testing and Reliability

Understand Fleet Level,

Warranty Exposure

• How will my supply chain

decisions or requirements

affect my fleet life?

• What is the optimal bearing

for my operational plan?

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

Serialized Asset Testing

Understand Serial Level, Duty Cycle Life Extension

• How will changing my real-life operating conditions, remanufacturing, and maintenance extend the life of bearings in the field?

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

What Business Challenge Exists?

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

Conceptual Design

Detailed Design

PrototypePhysicalTesting

Launch

Customer Tests Product in the FieldFailure

Could this perform better?

Computational Testing – Perform 100’s of tests before prototyping

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

4 Main

Features

Vertical

ApplicationsOnline

Help

Private

Customer

Libraries

Online

Support

DigitalClone Technical Approach

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

1) DigitalClone System™

Loads & Requirements &

System Life

6) DigitalClone Live™ Output

Predict-Acquire-Confirm-

Control

2) DigitalClone Material™

Characterize & Create

Microstructure Model

3)DigitalClone

Component™ Friction, &

Lubrication Surface

Treatments

5) Predict Component

Failure Mode/Failure Life

4) Simulate Stress in

Microstructure - Predict

Crack Initiation &

Propagation

Superfinish

Ground Finish

Patents Pending

Failure Modes Ready for

Implementation

• Micropitting Fatigue

• Bending Fatigue

• Spalling Fatigue

• Fretting Fatigue

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

Bearing SpallingGear Pitting

Bending Fatigue Spline Fretting

Failure Modes in R&D

Released 2014

• White Etching

• Metal Wear (Abrasion, Adhesion, Scuffing)

• Corrosion Fatigue

• Composite Delamination

• Coating Degradation

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

Corrosion Fatigue and Wear

Composite Laminate

Metal Wear

White Layer Etching

Computational Testing Applications

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

Component Lifecycle

Prediction

Assembly/System

Lifecycle Prediction

Fleet Analysis,

Monitoring, & Reporting

Manag

ed S

erv

ices

Saa

S/ A

aaS

Materials

Product Lifecycle

RequirementsDesign &

Test

Manufacture

WarrantyOperate &

MaintainReuse/Retire

Materials

Rotorcraft Gearbox Bearing

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

S-N plot for off-shelve (AISI-52100) and

aerospace-quality (SAE-4620) TGB taper roller

bearings

60

70

80

90

100

110

120

130

140

150

160

1 10 100 1000 10000

% o

f D

esig

n L

oad

L10 Life (Million Revolutions)

CLP AISI-52100 CLP SAE-4620 TIMKEN 52100

75%

100%

125%

150%

75% 100% 108% 115% 125% 140% 150%

Ax

ial

Lo

ad

Radial load

0-0.2 0.2-0.4 0.4-0.6 0.6-0.8

Failure probability for 4620 taper

roller bearing under different load

combinations

Rotorcraft Gearbox Bearing

November 20, 2014

Improving Bearing Life and Performance with Computational Testing17

Some RCF spalls/radial cracks in aerospace-quality bearing (clean steel):

Some RCF spalls/radial cracks in off-shelve bearings (steel with inclusions):

Subsurface cracks

initiated at inclusions

Radial cracksRCF spalls

Surface crack

Turbocharger Hybrid Bearing

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

18Sentient Confidential

300.00

350.00

400.00

450.00

500.00

550.00

600.00

650.00

700.00

750.00

0 10000 20000 30000 40000 50000 60000 70000

Fo

rce (

N)

Shaft speed (rpm)

Inner race Outer race

1300.00

1400.00

1500.00

1600.00

1700.00

1800.00

1900.00

2000.00

0 10000 20000 30000 40000 50000 60000 70000

Pre

ssu

re (

MP

a)

Shaft speed (rpm)

Inner race Outer race

0.00

500.00

1000.00

1500.00

2000.00

2500.00

3000.00

3500.00

4000.00

0 10000 20000 30000 40000 50000 60000 70000

L10 (

Millio

n s

haft

rev

olu

tio

ns)

Shaft speed (rpm)

Turbocharger Hybrid Bearing

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

19Sentient Confidential

19

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

0 10000 20000 30000 40000 50000 60000 70000

Failu

re r

ate

(%

)

Shaft speed (rpm)

General trends seem logical

Turbocharger Hybrid Bearing

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

20Sentient Confidential

• Miner’s rule:

• Assuming:

• n: total number of shaft revolutions required for failure under the

specified duty cycle

• FS (safety factor) = 1

n = 2579.43 million shaft revolutions3.88E-4 n = 1

Duty

cycle

Gearbox Bearing System

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

• Motivation/Problem: Premature cracking on

wind turbine gearbox bearings (NU232,

NU2326, NU2334, NU2336)

• Sentient Objectives:

– Simulate radial cracking and early failure

– Determine problem areas and best fix

Gearbox Bearing System

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

• Case 1: nominal loading condition with no hoop stressNominal Loading High Loading

No Hoop Stress Case 1 – No Failures Case 2 – Radial Cracks

and Pitting/Spalling

With Hoop

Stress

Case 3 – Spalling/Pitting, No

Radial Cracking

Case 4 – Spalling/Pitting,

Little Subsurface Damage

Gearbox Bearing System

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

#4 #3

#2 #1

Premature failure: including hoop stress

Hoop stress effect

Nominal load

Higher load

Exp. Data (Harris & Barnsby)

Jalalahmadi-Sadeghi

Lundberg-Palmgren Theory

Raje-Sadeghi

S-N data for 52100 cylindrical roller bearing (CRB)

Business Challenge Solution

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

Conceptual Design

Detailed Design

PrototypePhysicalTesting

Launch

Customer Tests Product in the FieldFailure

Could this perform better?

Computational Testing – Perform 100’s of tests before prototyping

Business Challenge Solution

November 20, 2014

Improving Bearing Life and Performance with Computational Testing

Conceptual Design

Detailed Design

PrototypePhysicalTesting

Launch

Customer Tests Product in the Field

Computational Testing – Perform 100’s of tests before prototyping

Improving Bearing Life and Performance

with Computational Testing