Structural Health Monitoring of Offshore Wind...
20
Structural Health Monitoring of Offshore Wind Structures Current Industry Practice and Roadmap Offshore Tage 2019
Transcript of Structural Health Monitoring of Offshore Wind...
Structural Health Monitoring of Offshore Wind
Structures
Current Industry Practice
and Roadmap
Offshore Tage 2019
Airwerk Produkte und Dienstleistungen
Intelligente Bauwerke &
Asset Management
Windmessungen Prototypen-
vermessungen
Be
ratu
ng
Konzepterstellung
Beobachtungsmethode (EC 7)
Zulassung im Einzelfall
Bauwerksinspektion
Lebenszeitverlängerung
Risk und Asset Management
Konzepterstellung
Betreuung
Baugenehmigungsverfahren
Konzepterstellung
En
gin
ee
rin
g Datenanalyse und Reporting
Lebensdaueranalyse
Materialermüdung
Eigenfrequenzanalyse
Bauwerksreserven
Zustandsanalyse
Datenanalyse und
Reporting
Windpotentialanalyse
Design Prüfung und
Optimierung
Me
sste
ch
nik Strukturmonitoringsysteme
Schwingungsüberwachung
Lastmessungen
Schadenserkennung
Webportallösungen
Windmessmasten nach
IEC61400-12
Leistungskurven-
vermessungen
projektspezifisch
18.03.2019 2
SHM in Offshore Wind: a ‘History’
18.03.2019 3
2007 2010 2015 20192013/14
BSH standard ‚Konstruktion‘: 10% SHM
First commercial German offshore Wind project BARD I
VDI starts work on VDI4551
Revisied BSH standard: Monitoring of foundation elements
VDI4551 will be published
First monitoring project airwerk
Airwerk joins VDI4551
More than 100 airwerk SHM systems operating
SHM in most European offshore wind
farm projects
Trends through all industries: digitalization, industry 4.0
Trends through all industries: risk based asset management, smart infrastructure….
SHM: What, Why and How – a History
18.03.2019 4
BSH 2007: ‘…inspection of the support structure by a condition
inspection system (CMS) for at least 1/10 of the offshore
wind turbines.’
What, why and how not defined…
BSH 2015: ‘…shifting, deformation, component stress and
frequencies, shall be measured and recorded
(monitoring) in the area of the foundation elements at
representative offshore wind turbine sites.’
VDI 4551: aims to fill the information gap
Early projects tended to lack clear
monitoring aims and to feature too
many sensors.
Monitoring Targets – Current Industry
Practice
18.03.2019 5
Monitoring Target defined by VDI 4551 Current IndustryPractise
Trend
Load Carrying Capacity Yes Up
Servicability Few projects Up
Lifetime / Lifetime Prolongation Few Projects Up
Condition Based Maintenance No No trend
Risk Based Asset Management Methods No No trend
Fault Detection No No trend
Control Optimization No No trend
Design Verification Very few projects Up
There is unexploited industry potential
Monitoring Methods – Current Industry
Practice
18.03.2019 6
Monitoring Methods defined by VDI 4551 Current IndustryPractise
Trend
Monitor Actions on Structures Yes Up
Internal forces yes Up
Dynamic Structure Behaviour Few projects Up
Condition Indicators Few projects Up
Model based Condition monitoring Few examples Up
Use of SHM in Asset Management no No trend
Example: Load Carrying Capacity, Serviceability
VDI Target / Method Current Industry
Practice
Typical parameters Trend
Load Carrying Capacity Yes. Acceleration, inclination and other
displacements, strain
Up
Serviceability Few examples Acceleration, inclination Up
Action on Structures yes Wind, waves, operational parameters Up
Internal Forces yes Strain Up
18.03.2019 7
Grout displacement Inclination
Example: Load Carrying Capacity
VDI Target / Method Current Industry
Practice
Typical parameters Trend
Load Carrying Capacity Yes. Acceleration, inclination and other
displacements, strain
Up
18.03.2019 8
Indirect measurement of underwater
pile displacements
Application:
Observation Method (EC7)
Fullfill BSH requirements 20mm
0,03°
Example: Lifetime
18.03.2019 9
Comparison of predicted fatigue damage
(design) and actual fatigue damage
(measured) for a period of 2 years of
offshore operation.
VDI Target / Method Current Industry
Practice
Typical parameters Trend
Lifetime Few projects Strain
Alternatively: acceleration, inclination
Up
Example: Periodic Inspection
18.03.2019 10
VDI Target / Method Current Industry
Practice
Typical parameters Trend
Condition based Maintenance
Risk based Asset Management
No Acceleration, inclination, actions on
structure, Operational parameter
No trend
Automatically
measured data
Data taken
manually
During periodic
inspection
Example: Periodic InspectionCurrent industry practise falls short of possibilities
18.03.2019 11
VDI Target / Method Current Industry
Practice
Typical parameters Trend
Condition based Maintenance
Risk based Asset Management
No Acceleration, inclination, actions on
structure, Operational parameter
No trend
Source: API RP 581, 2008
Example: Fault DetectionIndustry doesn’t expect faults
Pitch algorithm adapted by WTG
manufacturer
18.03.2019 12
VDI Target / Method Current Industry
Practice
Typical parameters Trend
Fault Detection No Acceleration, inclination, actions on
structure, Operational parameter
No trend
Example: Dynamic Structure Behaviour
Eigenfrequencies are used for design verification and damage
detection
18.03.2019 13
VDI Target / Method Current Industry
Practice
Typical parameters Trend
Dynamic Behaviour Few projects Acceleration, inclination, Up
Example: Model Based Monitoring
18.03.2019 14
Comparison of measured and expected
structure behaviour allows root cause
identification.
In this example, scour at 5 jacket legs was
correctly predicted.
VDI Target / Method Current Industry
Practice
Typical parameters Trend
Model Based Monitoring Few examples Acceleration, inclination, strain Up
Dynamic Behaviour Few examples Acceleration, inclination Up
Roadmap – Next Steps
18.03.2019 15
Learning Phase
- Selected structures
- Extensive
instrumentation
Structure picture source: BSH
Standard Design, 2015
Mature Phase
- all structures
- Simple but well choseninstrumentation
- Use of KPIs
Maturity of Industry
How many structures should be monitored?
ACCELERATION
INCLINATION
airwerk SHM System
18.03.2019 16
ACCELERATION
INCLINATION
Enables:
- Load assessment
- Lifetime
- Design verification
- Serviceability
- Dynamic behaviour
- Fault detection
Asset Management
Displacements from acceleration data don’t reflect quasi
static structure behaviour (slow movements)…
…but allow accurate estimates of dynamic loads
airwerk SHM System: Estimate Loads
from ACC Data
18.03.2019 17
Strain
Displacement
Top displacements correlate with bottom loads
ACC
Displacements from inclination data allow accurate
estimates of static and quasi static loads
airwerk SHM System: Estimate Loads
from INC Data
18.03.2019 18
Strain
Displacement
Top displacements correlate with bottom loads
INC
Roadmap: Next Steps
18.03.2019
19
Definition of parameter limits in EPC contracts neededServicability
- Inclination limits
- Vibration limits
Load Carrying Capacity
- Internal force limits
Design Verification
Grouted connections (ZiE)
Observation Method
- Load limits
- Permanent displacement limits
Lifetime
- Fatigue load limits
Picture source: BSH Standard Design,
2015
Aim: save operation of WTGs over 25 years
Roadmap: Next Steps
18.03.2019
20
Structural Health Monitoring needs to become integral part of riskand condition based Asset Management
