Insights to AGI Failure Investigation-VII.pptx

Insights to
Failure
Investigation
Date : 08 March 2023
By : Ts G Sujenthiran Eng Tech
:
© 2023 Approved Forensics Sdn Bhd 1

Qualifications & Certifications
Diploma in Marine Engineering - 2009
CoC Class III Motor – 2009
CoC Class II Motor - 2012
Registered Engineering Technologist - 2022
Professional Technologist - 2022 MSc Project Management - 2021

American Eagle Tankers (8 years)
• 2008 – 2009, Engineering Cadet
• 2009 – 2011, 4th Marine
Engineer
• 2011 – 2013, 3rd Marine
Engineer
• 2013 – 2014, Shipbuilding and
NS5 Project Engineer
• 2014 – 2015, 2nd Marine
Engineer

Sunway Group (3 + yrs)
• 2016 – 2018, Head of
Engineering
• 2018 – 2019, Chief Engineer

Approved Group International (3+ years)
• 2019 – 2022, Forensic Engineer
• 2023 – Snr Forensic Engineer/
Vice President
(Mechanical/Marine)

• Marine engineering
related investigation
• Engineering related
investigation
• Building and
construction related
investigation
• All types of heavy
machinery,
troubleshooting,
repair, maintenance,
operation and
restoration
Expertise

Investigation Framework Case Study 1 Case Study 2
AGI Statistics
AGENDA
Bonus
Takeaway

Failure Investigation
• To identify the root cause of failure through
understanding the failure mode and mechanism
• To prevent similar events happening in future
• To ensure no fraudulent elements in the failure

Flow of Investigation
Forensic
Engineering
Failure
Investigations
require the
process of
reverse
engineering a
failure
Failure
Mechanism
Failure Mode
Root Cause of
Failure

Failure Mechanism
• Deviant physical condition or physical state
• Nouns and adjectives

Failure Mechanism: Activities
• Damage assessment
• Damage pattern analysis

Failure Mode
• Deviant function or
behavior
• Verbs and adverbs

Failure Mode : Activities
• Research
• Knowledge
• Experience

Root Cause of Failure
• First condition or incident
• Contributory factors and
failure modes cannot serve
as root cause

Root Cause of Failure: Activities
Recognize
Need
Define
Problem
Generate
Hypothesis
Data
Collection
Data
Analysis
Test
Hypothesis
Finalize
Hypothesis

Quiz
• A drunk driver driving a sports car crashed onto a
light pole
• The accident caused the entire hood of the car to
crumble and deform

Quiz: Answer
Failure Mechanism Failure Mode Root Cause of Failure
Damage
Assessment
• Type of
deformation
• Dimensions of
the deformation
• Impact
• Magnitude of
impact (using
data from DA)
• Intoxicated driver

CS1: Biomass Boiler Chimney Collapse

Chimney
• Biomass boiler
• Internal power
generation
• Allegation:
Windstorm

Hypotheses
•Due to Windstorm?
•Or due to?

Physical Evidence: Corrosion

Hypothesis II: Corrosion Causing Factor

Design
• BS EN
1993-3-
2:2006
(Eurocode 3
- Design of
Steel
Structures,
2006)

Tolerance
For wind speeds up to 25 ms¯¹, an
unstiffened vertical circular
cylindrical shell, the membrane
stresses from external actions
may be determined from
membrane theory, treating the
cylinder as a global beam, where
shell bending effects can be
neglected, apart from the
circumferential bending moments
due to non-uniform wind
pressure distribution around
circumference”(Eurocode 3 -
Design of Steel Structures, 2006).

Microstructure of Metal
• Ferrite: soft and
ductile
• Pearlite: hard and
brittle
• Bonding of both to
form a marble like
view Ferrite
Pearlite

Metallurgical Analysis
• Section with
acceptable
thickness above the
corroded section
• Reduction of
pearlite can be
observed

Compounds
• Energy Dispersive
X-Ray (EDX)
• Acidic compounds
were present
• Promoting,
chemically induced
corrosion

Localized Corrosion!

Thickness
• Thickness at all
other sections of
the chimney were
above 5mm
• As per
calculations, they
were all within the
limit

Welding
Regions of heterogenous weld (source: ASM International, 2006)

Porosity Lack of fusion Undercut
Lack of root fusion Excessive
convexity
Asymmetrical throat size
Excessive root penetration Weld Cracking Lack of Penetration
Linear misalignment Crater Crack/Crater Pore Scatter

Welding
Defects:
Chimney

Discussion
• Wind speed was at 19 km/h, which is equivalent to 5 m/s
approx
• Thickness at thinned section below acceptable value
• Thinning observed due to corrosion
• Welding defects observed only at corroded section

Conclusion
• Material thinning
• Tear at thinned
section
• Collapse from
mid section
• Crumbling upon
impact on ground
• Uniform
corrosion due to
compounds
• Accelerated
corrosion at HAZ
zone
• Poor welding
work with
multiple defects

CS2: Steam Turbine Damage

Turbine: Shinko RB5
• Utilized for
internal power
generation
• During
maintenance
found to be
damaged badly
(July 2020)

Hypothesis
•Soil subsidence
led to
misalignment?
•Or?

Hypothesis II: Alternate Misalignment Factor

Turbine
Drive Shaft
Driven Shaft

Soil Subsidence
• Level
measurement:
ground, plinth,
turbine skid
• Measurements:
equal and levelled
: RULED OUT

Damage: Bearing
Heat Tint (Blue Tint) Uneven Wear
Extreme Friction

Damage: Shaft
Heat Tint (Blue Tint)
Friction
Uneven Wear

Wear & Tear?
• Does wear and tear
lead to heat tint?
• Normal wear and
tear is uneven?

Maintenance Record
• Maintenance
Summary: Bearings
have been changed
annually
• 2020 July all
bearings failed
together with the
shaft
Month, Year Bearings
Changed
Metal Bearing (MB) Clearance (mm) Thrust Bearing (TB) Clearance (mm)
December, 2016 - Before After Before After
2113
2114
2115
2116
-
-
-
-
0.175
0.175
0.175
0.175
2117
2119
0.30
0.25
-
-
June, 2017 MB 2113
MB 2114
2113
2114
2115
2116
-
-
-
-
0.150
0.150
0.175
0.175
2117
2119
-
-
0.33
0.27
July, 2018 MB 2115
MB 2116
2113
2114
2115
2116
0.175
0.175
0.200
0.200
0.175
0.175
0.150
0.150
2117
2119
-
-
0.32
0.24
August, 2019 MB 2113
MB 2114
TB 2117
TB 2118
2113
2114
2115
2116
0.200
0.200
0.175
0.175
0.150
0.150
0.175
0.175
2117
2119
0.38
0.27
0.24
0.27

Misalignment?
• Uneven wear shows
misalignment was
present
• What caused the
misalignment?
• Was the alignment
checked after each
service?
• Was the backlash
checked after each
service?

Backlash?
Aligned: Good Rotation
Backlash!!!!!

Backlash

Backlash
Backlash Value: High

Misaligned
Bearings are replaced
Backlash effected

Discussion
• Soil subsidence - Ruled Out
• Misalignment - Evidence
• No backlash measurement record
• Backlash hits on gear teeth first
• Bearings not replaced as a set

Conclusion
• Uneven wear
• Material loss
• Elevated
temperature
• Spalling
• Friction and
abrasion
• Improper
Maintenance

3-Step Boiler Failure Investigation Framework
• One of a kind framework
• Formulated from years of hands on experience
• Proven industry results utilized by insurance
industry professionals and engineers
• Worth: USD 500.00

Step-1

Step-2

Step-3

Lets
Investigate
A Boiler Failure

Scan Me

Background
• Mackenzie Combie Steam Boiler (in use for 20 years)
• Boilerman discovered multiple second pass smoke tubes to
be failed during inspection internally before JKKP
inspections

Chronology
• Low water level alarm activated at control room
• Boilerman checks the manual gauge glass finds low water level of boiler to be true
• Water level keeps dropping
• Boilerman inspects feed water valve opened at 60%
• Water level keeps dropping, feedwater valve remains at 60%
• To prevent further water level, boilerman opens the feed water valve by pass valve to
allow more water into the boiler
• Within 15 to 20 mins the water level in boiler rises back to normal level
• The by-pass valve was shut and boiler back to normal operations
• Upon shutting the by-pass valve water level starts to drop back, in 2 hours time the low
water level alarm activates again
• Since then the manual by-pass valve was opened approximately every two hours when
the low water level alarm activated

Hair Line Cracks on Weldment

Tube Sample: Water Side

Tube Sample: Fire Side

Water Level Transmitter

Feed Water Valve Pneumatic Actuator

Common
Causes
1. Human
2. Human
3. Human
: Operations
: Maintenance
: Incompetence

0
5
10
15
20
25
30
35
40
2001200220032004200520062007200820092010201120122013201420152016201720182019202020212022
AGI Root Cause Statistics: 2001-2022
Operations Maintenance Incompetence Fraud Manufacturing Others

Q&A

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Insights to AGI Failure Investigation-VII.pptx

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