JEC COMPOSITES MAGAZINE - Issue #108 - October 2016 - 34

WIND ENERGY
offshore

Fastening solution for offshore
wind turbine maintenance hatch
bigHead Bonding Fasteners is regularly challenged to provide
custom-designed fastening solutions for its customers.

matthew stevens,
Managing Director
bigHead Bonding Fasteners Ltd.

W

hile the standard range of over
400 mild steel and stainless steel
"bigHeads" provides efficient
and effective discrete fixings, whether embedded or surface-bonded to composite
materials, there are some applications that
benefit from a design approach where the
characteristic bigHead welded fixing is engineered and adapted to actually improve
the final design, to enhance its performance
or reduce costs - and even to increase safety.

Fig. 1: A solution to reduce cost

34

Offshore wind turbines
One such situation that perfectly exemplifies this engineer-to-engineer process is
when Siemens began to investigate composite materials for nacelles used on its new
6-MW offshore wind turbines. In particular,
a composite maintenance hatch had been
designed to replace a steel panel and traditional bolt fixings were used to lock and
unlock it. This required two persons to perform the operation - one inside and one
outside the nacelle. Clearly, ease of access
and its related safety were problems to be
solved, in addition to reducing maintenance
costs. Siemens nacelle suppliers approached
bigHead and, together, they developed
a solution.
Thoroughly field proven
By surface bonding the 316 marine-grade
stainless steel bigHead to the outer skin of the
nacelle and passing the threaded stud section
through its composite structure, the panel is
easily secured or removed by a single person
from the much safer interior of the structure.
The bigHead's large perforated head allows
a generous flow of adhesive to firmly secure
it in position and its outer surface includes
an over-moulded insulation layer that safeguards the nacelle against lightning strikes
and matches the structure's colour.
bigHead worked with the customer through
a stringent development stage - prototyping and extreme testing the solution against
the harsh conditions the offshore wind tur-

jec composites magazine / No108 October 2016

bines need to endure until a final design was
agreed. Now in its third year of supply, the
solution has been thoroughly field proven.
Like all bigHead's produced at its Verwood,
UK factory, every production batch is tested
and documented with completely traceable results as part of the manufacturer's ISO
9001:2008 quality management system.
Over 50 years of experience
bigHead has been manufacturing its distinctive and leading brand of discrete bonding
fasteners for over 50 years and has extensive
experience across a wide range of industries
where formed and moulded composite
products require discrete and completely secure fixing. Applications range from carbon
fibre panel fixing in specialist and luxury car
production to building and construction,
railway carriage construction, marine and
boatbuilding and more.
More information:
www.bigHead.co.uk
SzilardL@bighead.co.uk

Focus
All bigHeads are supported with tensile strength
and torque performance data readily available
from the website at www.bighead.co.uk - along
with application downloads, drawing requests,
whitepapers and useful FAQs. bigHeads are
available for small- to large-scale production as
male studs, female collars and nuts, or pins and
customised fixings in a choice of BZP mild steel
or 316 stainless steel.
http://www.bigHead.co.uk http://www.bighead.co.uk
Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #108 - October 2016
