In recent years more and more demanding structures are designed, built and operated
to satisfy the increasing needs of the Society. This kind of structures can be denoted
as complex ones. Among large constructions arrangements, Offshore Wind Turbines
(OWT) are definitely complex structural systems, being this complexity related to
different aspects such as hard nonlinearities, wide uncertainties and strong
interactions, either among the single parts or between the whole structure and the
design environment.
On the whole, the quality of a complex system is denoted by the idea of
dependability, while for a structure the performances are connected to the property of
structural integrity, considered as the completeness and consistency of the structural
configuration. Even if these concepts have been originally developed, respectively, in
computer science and for aerospace applications they can be applied to other high
performance systems as OWT.
The present paper will show some specific aspects of the modern approach
for the design and the analysis of complex structural systems. In the first part of the
paper, the general aspects are recalled like the System Engineering approach and the
Performance-based Design. Attention is devoted to some important aspects, such as
the structure breakdown and the safety and performance allocations. In the second
part of the paper, a basic application of the concepts introduced is presented.
ARRL: A Criterion for Composable Safety and Systems EngineeringVincenzo De Florio
While safety engineering standards define rigorous and controllable
processes for system development, safety standards’ differences in distinct
domains are non-negligible. This paper focuses in particular on the aviation,
automotive, and railway standards, all related to the transportation market.
Many are the reasons for the said differences, ranging from historical reasons,
heuristic and established practices, and legal frameworks, but also from the
psychological perception of the safety risks. In particular we argue that the
Safety Integrity Levels are not sufficient to be used as a top level requirement
for developing a safety-critical system. We argue that Quality of Service is a
more generic criterion that takes the trustworthiness as perceived by users better
into account. In addition, safety engineering standards provide very little
guidance on how to compose safe systems from components, while this is the
established engineering practice. In this paper we develop a novel concept
called Assured Reliability and Resilience Level as a criterion that takes the
industrial practice into account and show how it complements the Safety
Integrity Level concept.
Structural integrity monitoring for dependabilityFranco Bontempi
Dependability of a structural system is a comprehensive concept that – by definition – describes the quality of the system as its ability to perform as expected in a way that can justifiably be trusted. One of the attributes of dependability is integrity, which can be interpreted as the absence of improper alterations of the structural configuration. The assessment of the integrity during the whole life-cycle can be carried out efficiently by implementing a monitoring system able to detect and diagnose any fault at its onset. The essential feature of the monitoring system dealt with in the paper is the elaboration of data gathered on site by a combination of simulation and heuristics. In detail, the first part of the paper deals with the extension of the concept of dependability, as formulated in computer science, to structural engineering. The second part illustrates a two-step hierarchical strategy for the assessment of the integrity of a structure through monitoring of its response under ambient vibrations; Bayesian neural network models are used for fault detection and diagnosis from observable symptoms. In the first step, the occurrence of any fault is detected and the relevant portion of the structure identified; in the second step the specific element affected by the fault is recognised and the intensity of the alteration of the structural performance
evaluated. The strategy is applied to assess the integrity of a long-span suspension bridge subjected to wind action and traffic loading. As the bridge is under design, measured data are simulated by analysing the response of a detailed FE model of the whole structural system. The final objective of the study is the optimal design of the integrity monitoring system for the bridge.
In recent years, structural integrity monitoring has become increasingly important in structural engineering and construction management. It represents an important tool for the assessment of the dependability of existing complex structural systems as it integrates, in a unified perspective, advanced engineering analyses and experimental data processing. In the first part of this work
the concepts of dependability and structural integrity are
discussed and it is shown that an effective integrity assessment
needs advanced computational methods. For this purpose, soft computing methods have shown to be very useful. In particular, in this work the neural networks model is chosen and successfully improved by applying the Bayesian inference at four hierarchical levels: for training, optimization of the regularization terms, databased model selection, and evaluation of the relative importance of different inputs. In the second part of the article,
Bayesian neural networks are used to formulate a
multilevel strategy for the monitoring of the integrity of long span bridges subjected to environmental actions: in a first level the occurrence of damage is detected; in a following level the specific damaged element is recognized and the intensity of damage is quantified.
ARRL: A Criterion for Composable Safety and Systems EngineeringVincenzo De Florio
While safety engineering standards define rigorous and controllable
processes for system development, safety standards’ differences in distinct
domains are non-negligible. This paper focuses in particular on the aviation,
automotive, and railway standards, all related to the transportation market.
Many are the reasons for the said differences, ranging from historical reasons,
heuristic and established practices, and legal frameworks, but also from the
psychological perception of the safety risks. In particular we argue that the
Safety Integrity Levels are not sufficient to be used as a top level requirement
for developing a safety-critical system. We argue that Quality of Service is a
more generic criterion that takes the trustworthiness as perceived by users better
into account. In addition, safety engineering standards provide very little
guidance on how to compose safe systems from components, while this is the
established engineering practice. In this paper we develop a novel concept
called Assured Reliability and Resilience Level as a criterion that takes the
industrial practice into account and show how it complements the Safety
Integrity Level concept.
Structural integrity monitoring for dependabilityFranco Bontempi
Dependability of a structural system is a comprehensive concept that – by definition – describes the quality of the system as its ability to perform as expected in a way that can justifiably be trusted. One of the attributes of dependability is integrity, which can be interpreted as the absence of improper alterations of the structural configuration. The assessment of the integrity during the whole life-cycle can be carried out efficiently by implementing a monitoring system able to detect and diagnose any fault at its onset. The essential feature of the monitoring system dealt with in the paper is the elaboration of data gathered on site by a combination of simulation and heuristics. In detail, the first part of the paper deals with the extension of the concept of dependability, as formulated in computer science, to structural engineering. The second part illustrates a two-step hierarchical strategy for the assessment of the integrity of a structure through monitoring of its response under ambient vibrations; Bayesian neural network models are used for fault detection and diagnosis from observable symptoms. In the first step, the occurrence of any fault is detected and the relevant portion of the structure identified; in the second step the specific element affected by the fault is recognised and the intensity of the alteration of the structural performance
evaluated. The strategy is applied to assess the integrity of a long-span suspension bridge subjected to wind action and traffic loading. As the bridge is under design, measured data are simulated by analysing the response of a detailed FE model of the whole structural system. The final objective of the study is the optimal design of the integrity monitoring system for the bridge.
In recent years, structural integrity monitoring has become increasingly important in structural engineering and construction management. It represents an important tool for the assessment of the dependability of existing complex structural systems as it integrates, in a unified perspective, advanced engineering analyses and experimental data processing. In the first part of this work
the concepts of dependability and structural integrity are
discussed and it is shown that an effective integrity assessment
needs advanced computational methods. For this purpose, soft computing methods have shown to be very useful. In particular, in this work the neural networks model is chosen and successfully improved by applying the Bayesian inference at four hierarchical levels: for training, optimization of the regularization terms, databased model selection, and evaluation of the relative importance of different inputs. In the second part of the article,
Bayesian neural networks are used to formulate a
multilevel strategy for the monitoring of the integrity of long span bridges subjected to environmental actions: in a first level the occurrence of damage is detected; in a following level the specific damaged element is recognized and the intensity of damage is quantified.
In recent years more and more demanding structures are designed, built and operated
to satisfy the increasing needs of the Society. This kind of structures can be denoted
as complex ones. Among large constructions arrangements, Offshore Wind Turbines
(OWT) are definitely complex structural systems, being this complexity related to
different aspects such as hard nonlinearities, wide uncertainties and strong
interactions, either among the single parts or between the whole structure and the
design environment.
On the whole, the quality of a complex system is denoted by the idea of
dependability, while for a structure the performances are connected to the property of
structural integrity, considered as the completeness and consistency of the structural
configuration. Even if these concepts have been originally developed, respectively, in
computer science and for aerospace applications they can be applied to other high
performance systems as OWT.
The present paper will show some specific aspects of the modern approach
for the design and the analysis of complex structural systems. In the first part of the
paper, the general aspects are recalled like the System Engineering approach and the
Performance-based Design. Attention is devoted to some important aspects, such as
the structure breakdown and the safety and performance allocations. In the second
part of the paper, a basic application of the concepts introduced is presented.
A new design for fault tolerant and fault recoverable ALU System has been proposed in this paper. Reliability is one of the most critical factors that have to be considered during the designing phase of any IC. In critical applications like Medical equipment & Military applications this reliability factor plays a
very critical role in determining the acceptance of product. Insertion of special modules in the main design for reliability enhancement will give considerable amount of area & power penalty. So, a novel approach to this problem is to find ways for reusing the already available components in digital system in efficient way to implement recoverable methodologies. Triple Modular Redundancy (TMR) has traditionally used
for protecting digital logic from the SEUs (single event upset) by triplicating the critical components of the system to give fault tolerance to system. ScTMR- Scan chain-based error recovery TMR technique provides recovery for all internal faults. ScTMR uses a roll-forward approach and employs the scan chain implemented in the circuits for testability purposes to recover the system to fault-free state. The proposed
design will incorporate a ScTMR controller over TMR system of ALU and will make the system fault tolerant and fault recoverable. Hence, proposed design will be more efficient & reliable to use in critical applications, than any other design present till today.
Information Assurance & Reliability ArchitectureSrikar Sagi
Information Assurance(IA)
A Systematic & Systemic practice of assurance-modeling that guarantees protection of systems, information & managing information risks such as Confidentiality, Integrity, Availability, Auditing (Authentication /Authorization/Logs etc) & Non-repudiation in relation to the use, processing, storage & transmission of information, restoration of systems/services and the corresponding/inter-related systems, their processes used for protection capabilities(s)
In recent years more and more demanding structures are designed, built and operated
to satisfy the increasing needs of the Society. This kind of structures can be denoted
as complex ones. Among large constructions arrangements, Offshore Wind Turbines
(OWT) are definitely complex structural systems, being this complexity related to
different aspects such as hard nonlinearities, wide uncertainties and strong
interactions, either among the single parts or between the whole structure and the
design environment.
On the whole, the quality of a complex system is denoted by the idea of
dependability, while for a structure the performances are connected to the property of
structural integrity, considered as the completeness and consistency of the structural
configuration. Even if these concepts have been originally developed, respectively, in
computer science and for aerospace applications they can be applied to other high
performance systems as OWT.
The present paper will show some specific aspects of the modern approach
for the design and the analysis of complex structural systems. In the first part of the
paper, the general aspects are recalled like the System Engineering approach and the
Performance-based Design. Attention is devoted to some important aspects, such as
the structure breakdown and the safety and performance allocations. In the second
part of the paper, a basic application of the concepts introduced is presented.
A new design for fault tolerant and fault recoverable ALU System has been proposed in this paper. Reliability is one of the most critical factors that have to be considered during the designing phase of any IC. In critical applications like Medical equipment & Military applications this reliability factor plays a
very critical role in determining the acceptance of product. Insertion of special modules in the main design for reliability enhancement will give considerable amount of area & power penalty. So, a novel approach to this problem is to find ways for reusing the already available components in digital system in efficient way to implement recoverable methodologies. Triple Modular Redundancy (TMR) has traditionally used
for protecting digital logic from the SEUs (single event upset) by triplicating the critical components of the system to give fault tolerance to system. ScTMR- Scan chain-based error recovery TMR technique provides recovery for all internal faults. ScTMR uses a roll-forward approach and employs the scan chain implemented in the circuits for testability purposes to recover the system to fault-free state. The proposed
design will incorporate a ScTMR controller over TMR system of ALU and will make the system fault tolerant and fault recoverable. Hence, proposed design will be more efficient & reliable to use in critical applications, than any other design present till today.
Information Assurance & Reliability ArchitectureSrikar Sagi
Information Assurance(IA)
A Systematic & Systemic practice of assurance-modeling that guarantees protection of systems, information & managing information risks such as Confidentiality, Integrity, Availability, Auditing (Authentication /Authorization/Logs etc) & Non-repudiation in relation to the use, processing, storage & transmission of information, restoration of systems/services and the corresponding/inter-related systems, their processes used for protection capabilities(s)
ANALISI DEL RISCHIO PER LA SICUREZZA NELLE GALLERIE STRADALI.Franco Bontempi
SOMMARIO
Il tema della sicurezza, quando si parla di gallerie stradali, assume ancora più importanza, dato che un banale incidente o un guasto di un veicolo possono degenerare in uno scenario che causa un elevato numero di vittime. Ad esempio, il 24 marzo 1999, 39 persone sono rimaste uccise quando un mezzo pesante che trasportava farina e margarina prese fuoco all’interno del Tunnel del Monte Bianco. Nella prima parte dell’articolo vengono spiegate le fasi logiche che un modello messo a disposizione dalla PIARC/OECD, il Quantitative Risk Assessment Model (QRAM) [1-2], segue nel processo di Assegnazione del Rischio, e come esso ricava i valori dei relativi indicatori. Nella seconda parte dell’articolo, invece, viene mostrata un’applicazione di tale modello su una galleria esistente che si trova nel sud Italia, accompagnata da un’analisi di sensitività sui parametri che influenzano maggiormente il livello di rischio.
RISK ANALYSIS FOR SEVERE TRAFFIC ACCIDENTS IN ROAD TUNNELSFranco Bontempi
IF CRASC’15
III THIRD CONGRESS ON FORENSIC ENGINEERING
VI CONGRESS ON COLLAPSES, RELIABILITY AND RETROFIT OF STRUCTURES
SAPIENZA UNIVERSITY OF ROME, 14-16 MAY 2015
Appunti sulle modellazioni discrete per ponti e viadotti.
Corso di GESTIONE DI PONTI E GRANDI STRUTTURE, prof. ing. Franco Bontempi, Sapienza Universita' di Roma
PGS - lezione 03 - IMPALCATO DA PONTE E PIASTRE.pdfFranco Bontempi
Appunti su piastre per impalcati di ponti e viadotti.
Corso di GESTIONE DI PONTI E GRANDO STRUTTRE, prof. ing. Franco Bontempi, Sapienza Universita' di Roma
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Transforming Brand Perception and Boosting Profitabilityaaryangarg12
In today's digital era, the dynamics of brand perception, consumer behavior, and profitability have been profoundly reshaped by the synergy of branding, social media, and website design. This research paper investigates the transformative power of these elements in influencing how individuals perceive brands and products and how this transformation can be harnessed to drive sales and profitability for businesses.
Through an exploration of brand psychology and consumer behavior, this study sheds light on the intricate ways in which effective branding strategies, strategic social media engagement, and user-centric website design contribute to altering consumers' perceptions. We delve into the principles that underlie successful brand transformations, examining how visual identity, messaging, and storytelling can captivate and resonate with target audiences.
Methodologically, this research employs a comprehensive approach, combining qualitative and quantitative analyses. Real-world case studies illustrate the impact of branding, social media campaigns, and website redesigns on consumer perception, sales figures, and profitability. We assess the various metrics, including brand awareness, customer engagement, conversion rates, and revenue growth, to measure the effectiveness of these strategies.
The results underscore the pivotal role of cohesive branding, social media influence, and website usability in shaping positive brand perceptions, influencing consumer decisions, and ultimately bolstering sales and profitability. This paper provides actionable insights and strategic recommendations for businesses seeking to leverage branding, social media, and website design as potent tools to enhance their market position and financial success.
You could be a professional graphic designer and still make mistakes. There is always the possibility of human error. On the other hand if you’re not a designer, the chances of making some common graphic design mistakes are even higher. Because you don’t know what you don’t know. That’s where this blog comes in. To make your job easier and help you create better designs, we have put together a list of common graphic design mistakes that you need to avoid.
Book Formatting: Quality Control Checks for DesignersConfidence Ago
This presentation was made to help designers who work in publishing houses or format books for printing ensure quality.
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Can AI do good? at 'offtheCanvas' India HCI preludeAlan Dix
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1. DEPENDABILITY OF OFFSHOREDEPENDABILITY OF OFFSHORE
WIND TURBINESWIND TURBINES
Franco Bontempi, Marcello Ciampoli, Stefania Arangio
University of RomeUniversity of Rome ““La SapienzaLa Sapienza””
Department ofDepartment of
Structural and Geotechnical EngineeringStructural and Geotechnical Engineering
Honolulu, March 17th 2010
2. OUTLINEOUTLINE
Conclusions
ConclusionsConclusionsConclusionsConclusions
System approach for structural engineering applications
IntroductionIntroductionIntroductionIntroduction
The concept of dependability
PartIPartIPartIPartIPartIIPartIIPartIIPartII
Application to an offshore wind turbine support structure
Bontempi F., Ciampoli M., Arangio S. – Dependability of offshore wind turbines
3. Definition of structure
Stefania Arangio - Structural integrity monitoring of long span bridges using adaptive models
“device for channeling loads that results from the use and/or presence of the
building to the ground”
STRUCTURE
This definition does not consider some important aspects:
INTERACTION AMONG
DIFFERENT
STRUCTURAL PARTS
INTERACTION
BETWEEN THE
WHOLE STRUCTURES
AND THE DESIGN
ENVIRONMENT
Interactions are
characterized by
nonlinearities and
uncertainties
COMPLEXITY
4. Structure vs. Structural System
STRUCTURE
SYSTEM APPROACH
STRUCTURAL
SYSTEM
“a set of interrelated
components working
towards a common
purpose”
INTERACTION AMONG
DIFFERENT
STRUCTURAL PARTS
INTERACTION
BETWEEN THE
WHOLE STRUCTURES
AND THE DESIGN
ENVIRONMENT
Interactions are
characterized by
nonlinearities and
uncertainties
COMPLEXITY
Bontempi F., Ciampoli M., Arangio S. – Dependability of offshore wind turbines
5. NASA System complexity
Bontempi F., Ciampoli M., Arangio S. – Dependability of offshore wind turbines
IntroductionIntroductionPartIPartIPartIIPartIIConclusionsConclusions
6. Structure vs. Structural System
Stefania Arangio - Structural integrity monitoring of long span bridges using adaptive models
STRUCTURAL
DECOMPOSITION
Bontempi F., Ciampoli M., Arangio S. – Dependability of offshore wind turbines
SYSTEM APPROACH
STRUCTURAL
SYSTEM
INTERACTION AMONG
DIFFERENT
STRUCTURAL PARTS
INTERACTION
BETWEEN THE
WHOLE STRUCTURES
AND THE DESIGN
ENVIRONMENT
Interactions are
characterized by
nonlinearities and
uncertainties
COMPLEXITY
7. Structural decomposition
Bontempi F., Ciampoli M., Arangio S. – Dependability of offshore wind turbines
IntroductionIntroductionPartIPartIPartIIPartIIConclusionsConclusions
8. OWT Structural decomposition
SCALE
DETAIL
LEVEL
FINITE
ELEM.
SYSTEM LEVEL MACRO LEVEL MESO-LEVEL MICRO-LEVEL
Wind farm Single turbine Single turbine
Individual
components
Idealized model
components
Approximate
shape of the
components
Detailed
shape of the
components
Detailed shape of
the connections
BLOCK elements BEAM elements SHELL and
SOLID elements
SHELL and
SOLID elements
9. OUTLINEOUTLINE
Bontempi F., Ciampoli M., Arangio S. – Dependability of offshore wind turbines
System approach for structural engineering applications
IntroductionIntroductionIntroductionIntroduction
The concept of dependability
PartIPartIPartIPartIPartIIPartIIPartIIPartII
Application to an offshore wind turbine support structure
10. How is possible to define (and measure ) the quality of complex structural
systems as the OWT farms?
We need a concept able to take properly into account the different aspects
related to conceptual and structural design, construction and maintenance
during the whole lifetime.
DEPENDABILITY
It is a global concept that describes the aspects assumed as relevant with
regards to the quality performance and its influencing factors (Bentley,1993)
In rigorous terms, the dependability of a system reflects the user’s degree of
trust in that system, i.e. the user’s confidence that the system will operate as
expected and will not “fail” in normal use (Sommerville, 2000): the system
shall give the expected performance during the whole lifetime
Dependability (1)
Bontempi F., Ciampoli M., Arangio S. – Dependability of offshore wind turbines
13. ReliabilityReliability: the system capacity of failure-free operation over a
specified time in a given environment for a given performance
(can be expressed quantitatively by a probability … )
AvailabilityAvailability: the system capacity (or readiness) at a point in time
of being operational and able to perform as required (can be
expressed quantitatively by a probability … )
MaintainabilityMaintainability: the system attribute concerned with the ease of
repairing the system after a failure has been discovered or
improving the system to include new features
Active performance
Bontempi F., Ciampoli M., Arangio S. – Dependability of offshore wind turbines
IntroductionIntroductionPartIPartIPartIIPartIIConclusionsConclusions
14. IntegrityIntegrity: absence of alterations of structural response (related to
the completeness and consistency of the structural configuration)
SafetySafety: is a property of the system that reflects its ability to
operate, normally or abnormally, without danger of causing
human injury or death and without damage to the system’s
environment (safety-related prescriptions usually exclude
undesirable situations, rather than specify required
performances)
SecuritySecurity: The system property that reflects the system’s ability to
protect itself from accidental or deliberate external attack
(robustnessrobustness)
Passive performance
Bontempi F., Ciampoli M., Arangio S. – Dependability of offshore wind turbines
IntroductionIntroductionPartIPartIPartIIPartIIConclusionsConclusions
15. Reliability and safety are related but distinct
o In general, reliability (and availability) is necessary but not sufficient
condition for system safety
o Reliability is concerned with conformance to a given specification for a
given performance
o Safety is concerned with ensuring system cannot cause damage
irrespective of whether or not it conforms to its specification
ReliabilityReliability SafetySafety
SecuritySecurity
It is an essential pre-requisite for availability, reliability and safety.
Bontempi F., Ciampoli M., Arangio S. – Dependability of offshore wind turbines
IntroductionIntroductionPartIPartIPartIIPartIIConclusionsConclusions
16. Failure
Fault
Error
Permanent interruption of the system
ability to perform a required function
under assigned operating conditions
THREATS The system is in an incorrect state: it
may or may not cause failure
Defect that represents a potential
cause of error, active or dormant
Fault managing
Fault detection
Fault diagnosis
MEANS
Fault tolerant
design
Inverse problems
17. ATTRIBUTES
THREATS
MEANS
RELIABILITY
FAILURE
ERROR
FAULT
FAULT TOLERANT
DESIGN
FAULT DETECTION
FAULT DIAGNOSIS
FAULT MANAGING
DEPENDABILITY
of
STRUCTURAL
SYSTEMS
AVAILABILITY
SAFETY
MAINTAINABILITY
permanent interruption of a system ability
to perform a required function
under specified operating conditions
the system is in an incorrect state:
it may or may not cause failure
it is a defect and represents a
potential cause of error, active or dormant
INTEGRITY
ways to increase
the dependability of a system
An understanding of the things
that can affect the dependability
of a system
A way to assess
the dependability of a system
the trustworthiness
of a system which allows
reliance to be justifiably placed
on the service it delivers
SECURITY
High level / active
performance
Low level / passive
performance
ATTRIBUTES
THREATS
MEANSMEANS
RELIABILITYRELIABILITY
FAILURE
ERROR
FAULT
FAULT TOLERANT
DESIGN
FAULT TOLERANT
DESIGN
FAULT DETECTIONFAULT DETECTION
FAULT DIAGNOSISFAULT DIAGNOSIS
FAULT MANAGINGFAULT MANAGING
DEPENDABILITY
of
STRUCTURAL
SYSTEMS
AVAILABILITY
SAFETY
MAINTAINABILITY
permanent interruption of a system ability
to perform a required function
under specified operating conditions
the system is in an incorrect state:
it may or may not cause failure
it is a defect and represents a
potential cause of error, active or dormant
INTEGRITY
ways to increase
the dependability of a system
An understanding of the things
that can affect the dependability
of a system
A way to assess
the dependability of a system
the trustworthiness
of a system which allows
reliance to be justifiably placed
on the service it delivers
SECURITY
High level / active
performance
Low level / passive
performance
Dependability
Bontempi F., Ciampoli M., Arangio S. – Dependability of offshore wind turbines
18. Analysis and design of complex structural systems
Stefania Arangio - Structural integrity monitoring of long span bridges using adaptive models
STRUCTURAL
SYSTEM
INTERACTION AMONG
DIFFERENT
STRUCTURAL PARTS
INTERACTION
BETWEEN THE WHOLE
STRUCTURE AND THE
DESIGN ENVIRONMENT
Interactions are
characterized by strong
character, nonlinearity
and uncertainty
COMPLEXITY
DECOMPOSITION
STRATEGY
SYSTEM
APPROACH
QUALITY
ON THE WHOLE
FOR THE
STRUCTURAL
SYSTEM:
DEPENDABILITY
ATTRIBUTES
THREATS
MEANS
STRUCTURAL INTEGRITY
PERFORMANCE
BASED DESIGN
IntroductionIntroductionPartIPartIPartIIPartII
ConclusionConclusion
ss
19. OUTLINEOUTLINE
Bontempi F., Ciampoli M., Arangio S. – Dependability of offshore wind turbines
1/31
System approach for structural engineering applications
IntroductionIntroductionIntroductionIntroduction
The concept of dependability
PartIPartIPartIPartIPartIIPartIIPartIIPartII
Application to an offshore wind turbine support structure
20. Progressive loss of structural integrity
105m
35m
• Water level: 35 m
• Heigth of the structure
above water level:
105 m
• Pile length under sea bed
• Steel 355
•Turbine 5/6 MW
For wind farms with a lot of
structures it is interesting to
investigate the ability of the
system to sustain further levels of
demand after the ULS up to
extreme loading conditions
Bontempi F., Ciampoli M., Arangio S. – Dependability of offshore wind turbines
IntroductionIntroductionPartIPartIPartIIPartIIConclusionsConclusions
21. Description of the analysis (1)
The survivability of the system is investigated allowing large damage developing
inside the structural system: the spread of the plasticity is allowed until the last
configuration of equilibrium is reached
Non linear analysis:
-Material plasticity
-Large displacements
Integer structure (ULS) Loss of structural integrity
λ = 1.00 λ = 1.44
22. Increase of damage from the reference baseline ULS configuration to
the last equilibrium configuration
λ = 1.44λ = 1.00 λ = 1.32λ = 1.10
Description of the analysis (2)
Bontempi F., Ciampoli M., Arangio S. – Dependability of offshore wind turbines
23. Measuring the loss of integrity
1st freq
2nd freq
3rd freq
A quantitative measure can
be obtained considering the
modal behavior
Load multiplier
Frequencies
24. OUTLINEOUTLINE
Bontempi F., Ciampoli M., Arangio S. – Dependability of offshore wind turbines
System approach for structural engineering applications
IntroductionIntroductionIntroductionIntroduction
The concept of dependability
PartIPartIPartIPartIPartIIPartIIPartIIPartII
Application to an offshore wind turbine support structure
25. Conclusions
Offshore wind turbines (OWT) are complex structural systems
Their complexity is related to:
- nonlinearities
- uncertainties
- interaction between the parts
- interaction between the whole structure and the environmental
design
University of Rome “La Sapienza”
A global concept is needed to the define the quality of the OWT
in a comprehensive way
DEPENDABILITY
26. Conclusions (2)
The concept of dependability has been applied to OWT support
structures to investigate the survivability of the system in
presence of extreme actions
University of Rome “La Sapienza”
λ = 1.44λ = 1.00
The increasing of damage from
the reference ULS configuration
has been considered by means of
the load multiplier and considering
the modal behavior of the structure