risk based asset integrity management by ode

8/10/2019 Risk Based Asset Integrity Management by Ode

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Risk based Asset Integrity Management (RAIM)

1. Risk based Asset Integrity Management (RAIM) - Overview2. What is Risk based Asset Integrity Management

3. Risk Based Integrity Management procedure

4. Risk-Ranking of Structure Qualitative

5. Probability of Failure Categorisation

6. Consequence of Failure Categorisation

7. Risk Ranking Quantitative8. Risk based design

9. Risk based inspection

10. Risk based repair -- Cost-Benefit Analysis

11. Analysis Types

12. Structural Failure Probability Calculation for Storm Case13. General Structural Failure Probability Calculation

14. Progressive Collapse Analysis

15. Ship Impact Analysis

16. Typical FE analysis For a Semi sub Global Model

17. Fine mesh FE model for the critical central K node

18. Fine mesh FE model for Pontoon column intersection19. Solid FE model of tubular joint

20. Corrosion/Strength: Probabilistic Methods


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Risk based Asset Integrity Management (RAIM) -

Overview

Risk based Asset Integrity Management (RAIM) -

Overview

Asset Integrity

Management

Risk Based

Design

Condition

Assessment

Inspection Planning

Asset

Replacement

Planning

Remnant Life

Fitness for Purpose

Extended Life

On-line Monitoring

Strong Vibration

Risk Based Inspection Planning

Inspection Scheduling

Risk centered

maintenance

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What is Risk based Asset Integrity

Management An integrated service that considers all facets of a facility or

installation to establish, manage and optimize the through liferisk profile.

Risk based design

Risk based inspection

Risk based repair

Risk centered maintenance

Benefit

Optimise total cost of maintenance

Quantification of risk levels

Reduce disruption to operations

Supports Asset change of use / life extension / resale

Long term reliability, safety and reduced operating cost

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Risk Based Integrity Management

procedure

Reliability

Prediction

Statistical

Analysis

Inspection/FR

Data

FE Analysis

Fracture/Fatigue

Assessment

Risk Ranking

Mitigation

Analysis

System/Design

Modelling

Hazard I.D. & Analysis

FTA/FMEA/CCA

HAZOP/FFA

Definitions

Severity

Categories

Likelihood Categories

Safety

Criteria/Req/Rules

Inspection, Replacement, Corrosion

Management Schemes Operation controls, Redesign

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Determine Consequenceof FailureDetermine Likelihood ofStructural Failure

Structure

Consequence

Likelihood

of

failure

Risk-Ranking of Structure - QualitativeRisk-Ranking of Structure - Qualitative


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Probability of Failure Categorisation

Cat Annual Probability Description

Quantitative Event Team Experience

5 >10-2 Almost certain The event could

occur at some time

The team know several

occurrence in recent

months

4 10-3 to 10-2 probable The event could

occur at some time

It is a occurrence in the

industry in the last year.

3 10-4 to 10-3 Possible The event could

occur at some time

The team know a few

occurrence but not in the

last few years

2 10-5 to 10-4 Unlikely The event could

occur at some time

Only few occurrence are

known of in the experiences

of the team

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Consequence of Failure Categorisation

Consequence of

FailureMember

characteristicsAsset loss

Business

interruptionSafety

Environment damage

Cat Qualitative General

5 catastrophe

Essential members

to the integrity of the

system

Extensive damage

>100 million USD100 days

Multiple fatality (or

permanent total

disabilities)

Massive effect, large scale (10

100 mile2) long term impact

4 Major

Essential members

to the operational

performance of the

system

Major damage 10

-100 million USD10 days

1 fatality (or

permanent total

disability)

major effect, medium scale (1 10

mile2) medium term impact (years)

3 Considerable

Non-Essential

members but failure

can impede theperformance of the

system.

Local damage 1-

10 million USD 3 days

Major injury /illness,

permanent partial

disability or lost time

injury (>4 days)

Local effect, medium scale (1 10

mile2) medium term impact(months),

2 significantRedundant member

through mitigation

Minor damage 0.1

- 1 million USD1 day

Minor injury/illness,

restricted duties or lost

time injury (


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Risk Ranking Quantitative

Consequence of failure

Probabilistic fracture mechanics includingfatigue, corrosion, POD, etc.

Extreme statistics analysis

Final fracture or collapse probability

Failure frequency, QRA, HAZOP

Production lossContractual penalty

Negative publicity

Cost of repairing

Threat to public health, environment

Probability of failure

Probability of failure

Low Moderate High

Consequence

of failure

High

Moderate

Low

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Risk based designRisk based design

Most of current offshore standards set the probability of failure to be

between 10-5 and 10-4

Codes and standards are based on generic cases

Risk based design can be used Probability of failure is based on specific case hence more economic

Develop Safety factors for specific site condition to achieve the same level of risk as in

standards

Calculate the level of risk for investment decisions

Risk reduction --- lower overall risks with the same investment

Cost reduction -- efficient use of resources for the same target risk level

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Risk based inspectionRisk based inspection

Risk Based Inspection (RBI) uses risk techniques to focus inspection

resources, as part of AIMS

The RBI process defines

where to inspect More inspection on higher risk items Less inspection on low risk items

when to inspect Time interval based on risk prediction

how to inspect

It is updateable based upon inspection findings

It is an ongoing process used throughout the life cycle of the facility

RBI Benefit

Risk reduction --- lower overall risks with the same inspection resources Cost reduction -- efficient use of inspection resources for the same target

risk level

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Risk based Repair -- Cost-Benefit Analysis

1. Assessment of differentremediation options to

determine most optimal

action

2. Focused on capital and

revenue protection RemediationCost

Remediation Alternative

Cost

Do nothing Do everything

Total Cost

Failure

Cost

Optimal

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Analysis Types

1. Linear analysis for ULS, FLS code checking

2. Structural failure probability analysis3. Non-linear Progressive Collapse (push over) Analysis

4. Finite Element Analysis

5. Advanced Fatigue Analysis

6. Fracture Mechanics

7. Corrosion Engineering

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Structural Failure Probability Calculation

for Storm Case

- Quantitative

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General Structural Failure Probability

Calculation

Requiring Pushover analysis to

determine failure

Best estimates applied for allquantities

Uncertainties represented

explicitly

FE analysis may be required

Total risk can be reduced through

1. Load Reduction

2. Strengthening

3. Reduction in uncertainties

Failure Probability Calculation

Value

Frequency

Mean Load Mean Resistance

Load Resistance

RRS S

Reserve Strength

Failure

Failure Probability Calculation

Value

Frequency

Mean Load Mean Resistance

Load Resistance

RRS S

Reserve Strength

Failure

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Progressive Collapse Analysis for Design

Against FireNon-linear structural response analysis is

used in fire response analysis to consider

thermal expansion effects, the degradation of

material strength with increased temperature,and the structural progressive collapse under

fire.

The results of advanced fire response analysismay be used to develop an optimised scheme

of passive fire protection for the structure.

Potential savings for a typical offshore

structure are in the range of 50% of theoriginal scope

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Ship Impact Analysis

Conventional single member analyses onlyutilise the energy dissipating capacity of theimpacted member.

The progressive collapse analysis takes intoaccount all the energy dissipation mechanismsand therefore is able to provide a more realistic

estimate of the resistance (or survivability) ofthe platform to ship collision. Thus a moreoptimal design or more realistic risk assessmentcan be achieved.

Utilising advanced analysis, a number of impactscenarios can be analysed quickly. This isespecially useful at the design stage.

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Typical FE analysis For a Semi sub Global

Model


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Fine mesh FE model for the critical central

K node


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Fine mesh FE model for Pontoon column

intersection


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Solid FE model of tubular joint

Tubulars are modelled with solid

brick elements in several layers

across the thickness for accurate

determination of local hot spotstresses


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T y p ic a l L o g - N o r m a l C o r ro s i o n R a t e D is t r i b u t io n

0

2

4

6

8

1 0

1 2

0 .0 0 .1 0 .2 0 .3 0 .4 0 .5 0 .6

C o r r o s i o n R a t e (m m /y e a r )

Probabilit

yDensityFunction

M a x . V a lu e

( 9 5 % o f N o n - Ex c e e d a n c e )

M in . V a l u e

( 5 % o f N o n - Ex c e e d a n c e )

Corrosion/Strength: Probabilistic Methods

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risk based asset integrity management by ode

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