PHM in context - University of Twente Research Information · Ronde Tafel PHM What is PHM ? • Prognostics & Health Management (PHM) • Concept – Optimize Life Cycle Management

Prof. dr. ir. Tiedo Tinga

Life Cycle Management

[email protected]

Nederlandse Defensie AcademieNetherlands Defence Academy

PHM in context

Dynamics based Maintenance

[email protected]

utwente.nl/time

Netherlands Defence Academy

Ronde Tafel PHM

My background

• NLDA– Optimize maintenance and LCM– Focus on military systems (ships, helicopters, vehicles)

• University of Twente– Predictive Maintenance based on physical models– Structural Health and Condition Monitoring – Focus on civil applications (windturbines, bridges, train/track)– Part of Maintenance Consortium TIME

› Collaboration 8 research groups @UT› Combining multiple disciplines

4-7-2017


Ronde Tafel PHM

Outline• Introduction

• Defining PHM

• Cases / applications

• Challenges

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Ronde Tafel PHM

The Maintenance Challenge• Critical systems require preventive maintenance • Challenge: when to do maintenance ? • Balance between

– costs» spare parts, repair, man hours» long intervals

– reliability / availability» no unexpected failures» short intervals

• Optimal approach – on-condition maintenance (just-in-time)– both efficient (costs) and effective (no failures)

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Ronde Tafel PHM

How to determine proper moment ?• Traditional approach: intervals based on

– estimate of future usage (OEM) often conservative

– collected failure data not always available (registration, PM)

– experience from the past not always representative

Experience-based and static

• Optimal approach– on-condition maintenance (just-in-time)– based on monitoring usage / loads / condition

Model-based and dynamic

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Ronde Tafel PHM

Detection or Prediction of failures ?• Condition Monitoring / Anomaly detection

(diagnostics)– Monitor degradation of system with sensors or data

+ actual condition is accurately known+ based on measurements, independent of model assumptions-- mainly diagnosis immediate action required

• Prediction techniques (prognostics)– Focus on prediction of remaining useful life (RUL)

+ maintenance can be planned in future-- complex models or analyses required

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Ronde Tafel PHM

Prognostics• Data- / experience-based approach

– Requires lots of (failure) data + some domain knowledge !– Data-mining

› Find correlations (represents past !)› Recognizes known failures (training)› Data analytics

• Model-based approach– Understand failure behaviour + loads– Also prognostics for changed operating profile– Monitor usage / loads / condition

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Ronde Tafel PHM

Dynamic maintenance – model based

Failure model

Zoom in to the level of the physical failure mechanism

Usage Platform / system Remaining life

Local Loads Service life /Damage accumul.

thermal / fluid / structural model

Usage monitoring

Load monitoring Condition monitoring

Prognostics

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Ronde Tafel PHM

• Prognostic distance

• Accuracy / reliability (false negatives / positives)

Prognostic performance

4-7-2017


PHM

Ronde Tafel PHM 4-7-2017


Ronde Tafel PHM

What is PHM ?• Prognostics & Health Management (PHM)• Concept

– Optimize Life Cycle Management of system, using advancedsensors, models, algorithms

• Main constituents– Diagnosis

› asses present condition of asset / system– Prognosis

› predict remaining life time of asset / system– Health Management

› use diagnosis / prognosis to take proper decisions on maintenance activities

• Origin– USA - development of F35 / Joint Strike Fighter – Also applied in electronics / vehicles

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Ronde Tafel PHM

sensors

data collection/registrations

data processing+ analytics

(physical) failure models

decision support

diagnosis

prognosis

health management

PHMCM / SHM

Pred.M.

Focus

RT

PHM elements

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Ronde Tafel PHM

• Smart layer– 9 piezo actuators / sensors

• Optical fibres– Fiber Bragg gratings– Strain, temp., moisture

• ComparativeVacuum Monitoring

Sensor developments

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CASES



Ronde Tafel PHM

• HUMS system available for monitoring– Usage flight hours, landings, conditions, etc.– Health mainly vibrations

• Maintenance primarely related to flight hours

• Identified critical components (Pareto + CMMS)– Cost drivers– Availability killers

• Determined failure mechanism + governing loads

NH-90 helicopter prognostics

Heerink, 2013

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Ronde Tafel PHM

• Landing gear shock absorber is critical• Time to failure not correlating to FH• Develop prognostic method

NH-90 helicopter prognostics

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Ronde Tafel PHM

• Mechanism: wear of seal(oil leakage)

• Relevant Failure Parameter: travelled distance # landings + weight

NH-90 helicopter prognostics (2)

i iV k Fs=

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Optimization of maintenance

Mission type(incl. environment)

1. in harbour 2. training9. mission in

polar conditions

…….

Mission phase 1. transit 2. surveillance 12. anti-submarine…….

27% 17% 4%

10% 15% 15%

Subsystem usage

Gas turbine

2 (out of 4) diesel generators active

1 water chiller active

SMART-L

70%

0%

30%

2 water chillers active

3 water chillers active

70%

0%

0%

Mission type selection + mission duration (Tm)

• Determine optimal interval for subsystems• Depend on usage profiles• Integrate into ship level optimum



OPV system - installation - component

Diesel engine• Liner / ring

• Valves

• Bearing

• Many others …

Radar• PCB’s

• Bearing

• Many others …



Other applications• Predictive Maintenance

– Off-shore wind turbines drive train– Rail track / switch wear prediction– Production facilities – Electronics / PV modules

• Health & Condition monitoring– Bridges / sewer systems / wind turbine blades

• Decision support / LCM– Relating degradation to usage profiles– Selection of prognostics / CM system– Business case



CHALLENGES



PHM challenges• Relevant & high quality data is crucial

– How to select, collect and access ?• Developing and validating predictive models is

time-consuming – Not feasible for all systems how to prioritize ?– How can development be accelerated ?

• How to address gap component vs. system level ?• Also data-driven methods require system

knowledge + sufficient number of examples of anomalous behavior – How to generalize / automate ?– How to combine two approaches + CM ?




Documents

PHM in context - University of Twente Research Information · Ronde Tafel PHM What is PHM ? • Prognostics & Health Management (PHM) • Concept – Optimize Life Cycle Management