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F+L Week 2015 | 10-13 March 2015
of the reciprocating internal combustion
engine. The modern engine presents many
challenges to lubricants and materials,
especially as engine speed, temperature and
specific output continue to rise. This talk will
emphasise the latest hardware advances,
such as variable valve timing mechanisms, tur-
bo- and super-chargers and trends in engine
downsizing.
Edward Becker is former
president and fellow of the
Society of Tribologists and
Lubrication Engineers. He
holds a PhD in mechanical
engineering from the University of Michigan.
Ed retired from General Motors after more
than 30 years, mostly in the Powertrain
division working on a variety of GM engines
and transmissions. In addition, Ed is the
president and founder of Friction & Wear
Solutions, LLC, a consulting firm dedicated
to solving tribology problems. Also of note,
he is a licensed professional engineer in
Michigan and holds six U.S. patents.
Tribological Study of
OffshoreWind Turbine
Lubricants and Their
Interactions
Tuesday 10 March 14:00 | 15:30
NARASIMALU SRIKANTH
NanyangTechnological University
Drivetrain systems mainly using gear box
sub-systems or directly driving in offshore
conditions are vulnerable to high defect
rates and uncertainty (e.g. offshore wind
and marine drivetrains). Various stressors
aggravate the failures due to environmen-
tal effects such as temperature, humidity
and salinity. Thus the bearing capacity
decreases and thereby the dynamics of the
drivetrain are affected. Existing literature has
limited information on lubricant and bearing
steel failure in relation to tribology failure
modes, such as micropitting and white
structure flaking, which needs detailed
basic research.
Accordingly, in this study efforts are
made through developing special test rigs
that mimic actual drivetrain conditions. In
this study, a test rig has been developed
that mimics actual tribological conditions
in large wind turbine drivetrain bearings.
Lab level results show similar bearing failure
modes of large wind turbines. Hence, the
test method is further utilised to study
tribological performance of both steel and
lubricants. Field results show when the
lubricant fails, the drivetrain exhibits poor
performance and shorter life with heavier
damage. Accordingly, in this study the tribo-
logical behaviour of the bearing is studied
using a combination of experimentation
and simulation studies. The results provide
a detailed understanding of the lubricant
degradation mechanisms. In addition,
tribological failure of the bearing steel can
be explained by the present understanding
of the lubricant degradation mechanisms
and their interaction with steel under real
field-level operating conditions. In order
to avert such failures, attempts have been
made through deploying suitable functional
coatings, which will be discussed. The
overall understanding will help drivetrain
designers to select the right steel and
lubricants to achieve optimal design in
harsh conditions, such as for wind turbine
drivetrain operation in offshore conditions.
Narasimalu Srikanth iswith
ERI@N (Energy Research
Institute at NanyangTechnolog-
ical University) as the Program
Director and Senior Scientist
leading thewind andmarine renewable
research. Previously hewas leading key
research activities in tribology of wind turbines
at Vestaswind systems and clean room
semiconductor manufacturing systems inASM
Technology Singapore. Prior to that, he
designedhigh-speedgear manufacturing
machinery and lubricant selection at Tata
Engineering (Pune, India). He receivedhis first
master’s degree from theDepartment of
Mechanical Engineering at the Indian Institute
of Technology, Bombay, India, in the area of
design engineering andhis secondmaster’s
degree inmaterials engineering. Narasimalu
further pursuedhis doctoral degree (PhD) from
theNational University of Singapore (NUS) with
a specialisation inmaterials andmechanical
engineering. He further pursuedgettinghis
seconddoctoral degree in technology
management from theNational University of
