The carbon fiber-sandwich composite simulator
dome (which is 7.67 meters (25.16 ft)
in diameter and 4.52 meters (14.83 ft) high)
was manufactured by Hahlbrock GmbH
(Wunstorf near Hannover) who has developed
special expertise in the production of
large technical moldings.
The dome comprises five main components:
platform, spherical dome, roof, doorframe and
door. Carbon fiber sandwich construction,
which was used throughout, was chosen to
produce a finished structure that would offer
a high strength-to-weight ratio and high
stiff ness values. Hahlbrock specifi cally chose
Diab foams – having successfully used them for various shipbuilding and industry projects in the past – due to their consistency and high quality.
Under normal operating conditions, the dome is subjected to acceleration forces of up to 1 g as it travels transversely at 10 meters per second (36 km/h). In an emergency it must be able to safely withstand deceleration forces of up to 2 g.
Both the self-supporting spherical dome
and the roof need to provide ultra-low
deflection properties even when experiencing
high dynamic loads to avoid any display problems
with the projected images. The roof also
has to carry the weight of the eight projectors.
The eight images are projected directly
onto the inner surface of the spherical dome
that has been finished with a robot-applied,
high-gain paint. The maximum allowable
deflection of the complete sphere is a few
millimeters and the maximum local deflection
is just 0.8 mm (0.03 in).
To meet these exacting specifications,
Hahlbrock used a special epoxy resin
infusion technique developed by the German
Aerospace Centre (DLR) in Braunschweig and
the Composite Technology Centre (CTC) in
Stade. The company also made extensive use
of 5 axis CNC machines to produce the molds
and accurately trim the core and the finished
Individual sheets of Divinycell structural
core measuring 2,440 x 1,220 mm x 50 mm
(96 x 48 x 1.96 in) were thermoformed to create
the correct profile. Then two preformed
cores were bonded together to achieve the
required core thickness of 100 mm (4 in).
Final fairing of the core surface was also
carried out by a 5 axis CNC machine.
The dome consists of 10 identical spherical
segments with each segment comprising
three preformed cores.