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National Aeronautics and Space Administration

www.nasa.gov

Mechanical Components Diagnostics

Research

1

Kelsen Elizabeth LaBerge

U.S. Army Research Laboratory

4th Propulsion Control and Diagnostics Research Workshop

December 11-12, 2013

Cleveland, OH


www.nasa.gov

Tribology & Mechanical Components Branch

Drive System Team Mission

• Conduct basic research and technology

development on mechanical components and drive

systems.

• Results lead to first principle understanding of

complex phenomena of component or system

operation in normal and extreme conditions.

• Technology transfer results in improved operation

efficiency and safety of Rotary Wing Aircraft.

2


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Technologies for Propulsion – Drive Systems

• Advanced Drive System Components and Systems

– Multi / variable speed drives

– Improved gear alloys

– Enhanced gear operation / control

– Composite material application to dynamic components

– Modified geometry gear design, bearings & system arrangements

• Lubrication Technology

– Improved loss-of-lubrication (longer time, lighter weight,…)

– Reduced power loss – windage drag reduction

• Condition Based Maintenance (CBM)

– Improved detection techniques – i.e. non-metallic sensors

– Improved data algorithms

– Validated methods – rotorcraft field verification

3


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What is CBM?

• Condition Based Maintenance:

– Application and integration of processes, technologies and

knowledge via a systems approach to improve aircraft reliability

and maintenance effectiveness [1]

• Goals:

– Reduce maintenance burden

– Increase aircraft availability

– Improve flight safety

– Reduce cost

4


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RW CBM Focus - Propulsion

Propulsion System Health

– Improved detection techniques

– Improved diagnostic algorithms

• Multi-sensor data fusion

• Performance metrics

• Damage magnitude assessment

– Validated methods – rotorcraft field verification

• Test methods representative of fielded faults

– Future prognostic algorithms

• Damage life prediction models – predict remaining useful life

Structural Health & Exceedance Monitoring

– Correlate aircraft operational parameters to component life.

Research enabled through partnerships between NASA, FAA and Army

5


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Condition Indicators (CI)

• A measure of detectable phenomena, derived from

sensors that show a change in physical properties

related to a specific failure mode or fault. [1]

6

Raw Data Snapshot

Algorithm Condition

Indicator (CI)

Vibration-based Mechanical Component Diagnostics

10 20 30 40 50 60 70-40

-20

0

20

40

Tooth Number

41

2

1

84

M8A

Nk

k i

Nk

k i

dd

ddN 22 23 24 25 26 27 280

1

2

3x 10

4

M8A Condition Indicator Results

(Not Continuous)

M8

A

22 23 24 25 26 27 280

200

400

600

800

1000

Continuous LoadL

oa

d (

hp

)

Runtime (hrs)

Run Time (s)


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Planetary Fault Detection

7

Objective:

Demonstrate diagnostics to detect

gear and bearing planetary system

faults in main-rotor gearbox

Approach:

Develop algorithms from seeded fault

tests on the OH-58 main-rotor

transmission (AATD/Bell OSST)


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Planetary Fault Detection

8

Fault

Status:

• Project complete

• Successfully identified the presence

and location of a planet tooth crack in a

blind test

• Sun tooth cracks were not detected with

this method. [2]


www.nasa.gov

SBIR – Embedded Data Acquisition Tools for

Rotorcraft HUMS (Ridgetop)

9

Objective:

Develop MEMS wireless sensor for fault

detection in rotorcraft transmission applications

Approach:

• Develop MEMS vibration-monitoring

accelerometer, microcontroller conditioner,

wireless transmitter, and receiving unit for

data collection.

• Mount directly on helicopter transmission

component of interest to measure

abnormalities and faults.

Status:

• OH-58 pinion tooth crack detection test

completed after 110 hrs.

• MEMS sensors operating successfully,

detected tooth fracture.

• MEMS tests for planetary planned.


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Acceleration,G's RMS

16

17

18

19


15

16

17

18

Run time, min

0 20 40 60 80 100 120 140


14

15

16

17

Accelerometer "R"

Accelerometer "T1"

Accelerometer "T2"

SBIR – Embedded Data Acquisition Tools for

Rotorcraft HUMS (Ridgetop)

10

Fractured OH-58

pinion tooth

T2

T1

R

MEMS Accelerometers

Last Day of Testing


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CI Performance in the Lab

Objective:

• Develop CI validation

methods in the lab that better

represent fielded faults

• Identify limitations using rig

tests

Approach:

• Perform tests in GRC Rig

• Evaluate CIs during naturally

occurring faults.

• Define Fault: Class, Mode,

Degree

• Document fault progression

• Verify (CI) Response

• Correlate faulted helicopter

gears

11

FM4 Detects Damage

SI Detects Damage

Torque and Debris

Spiral Bevel Gear Fatigue Test Rig


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CI Performance in a Helicopter

12

NGB Tail 04, Input Pinion SI

CI Performance/Sensitivity to Specific Gear Wear Modes

NGB Color

1

2

4

5

6

7

10

In_DA1 In_SI Out_DA1 Out_SI

4.3.4

spalling

6.1

Brittle Fracture

4.3.2

progressive

4.3.3

flake

4.2

micropitting

Gear Wear

Mode

AGMA 1010

Condition Indicator

Input Pinion Output Gear

CI vs. Gear Wear Analysis (50%)


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Hybrid Bearing Fault Detection

Objective: • Conduct seeded fault experiments of both standard

(steel rolling element) bearings and hybrid (ceramic

rolling element) bearings to examine the difference

in damage vibration and propagation

• Determine the effectiveness of currently used flight

sensors as compared to higher bandwidth research

sensors

Approach: • Obtain healthy data under normal loading

conditions, seed fault and propagate under normal

conditions

• Seed damage using a hardness tester and monitor

the vibration change during propagation under

normal loading

Status: • One hybrid and one steel test completed

• Steel bearing ran for 50 hours after material

removal

• Test rig load path concerns

• A fixture has been designed to make the process of

seeding bearing faults with a hardness tester in

angular contact bearings more repeatable

13

58 60 62 64 66 68 70 720

1

2x 10

4

Speed (

RP

M)

58 60 62 64 66 68 70 720

500

1000

1500

Load (

lbs)

Axial Load

Radial Load

58 60 62 64 66 68 70 720

0.05

Bearing E

nerg

y

58 60 62 64 66 68 70 720

0.05

Shock P

uls

e

Energ

y

Run Time (hrs)

Axial

Horizontal

Vertical - Research

Vertical - Flight

Fault seeded Material removed

Spall Progression

58 60 62 64 66 68 70 720

0.05

58 60 62 64 66 68 70 720

100

200

Run Time (hrs)

Oil

Debri M

onitor

FE

Mass (

mg)

Oil

Debris M

onitor

FE

Mass (

mg)


www.nasa.gov

Questions

[1] US Army, “Aeronautical Design Standard Handbook for Condition Based

Maintenance Systems for US Army Aircraft,” ADS-79C, January 2012.

[2] D. G. Lewicki, K. E. LaBerge, R. T. Ehinger, and J. Fetty, “Planetary

Gearbox Fault Detection Using Vibration Separation Techniques,”

presented at the 67th American Helicopter Society Annual Forum, Virginia

Beach, VA, 2011.

14

mechanical components diagnostics research - … components diagnostics research 1 ... national...

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