Diapositiva 1

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Introduction
General Layout
Structure
Mechanisms
SealingLatching
Handling Equipment
Base isolation
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Introduction
In the last decades of the XXth century the
development of new technologies such as the
segmented mirrors with active optics and the
adaptive optics broke the limitations in the
feasible diameter for the primary mirror and
caused the origin of the 8-10m class
telescopes. Considering the successful operation
of 8-10m class telescopes in operation as the
KECKs and the VLTs, both the American Community
and the European Community began to prepare the
next generation of telescopes, the Extremely
Large Telescopes. In Europe, the European
Organisation for Astronomical Research in the
Southern Hemisphere (ESO) launched in December
2006 the Detailed Study of the European Extremely
Large Telescope (E-ELT). The E-ELT is a 42m
segmented primary mirror telescope with a five
mirrors optical configuration.
Introduction
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General layout
General layout
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General layout
General layout
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Structure. General concepts
enclosure structure requirements
functional
structural
capacity
stiffness
operational
survival

• fully operational under maximum
• - snow
• ice
• wind

• withstand
• snow
• ice
• wind

• operational loads Sy 0.2/1.5
• survival loads Sy 0.2/1.1
• buckling

• not interfere with telescope volume
• deformations allow moving parts operated
• - azimuth rotation system
• - doors tracks
• - main crane
• - latching system
• seals tight
• - azimuth system
• - slit covering

Structure
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Structure. Doors structure
Large slit covering system as the main driver of
the structure design ? slit door structure as the
first issue to be developed Hyperestatic strategy
support for the sake of a compact solution ? two
bogies at the uppper rim, two at the lower rim
each of them running on a separate track Shear
stiffening in order to avoid guiding
difficulties An integrated design with the rest
of the dome
Structure
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Structure. Doors structure
Structure
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Structure. Doors drive mechanism
Each of the doors is supported at the lower part
of the two arch girders, by means of 4 bogies,
with four main wheels and four lateral wheels
each. One of the top bogies and one of the bottom
bogies are driven by means of a chain sprocket
mechanism.
Structure
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Structure. Doors drive mechanism
The bogies are driven by means of the sprocket
chain system, powered by an asynchronous
induction motor of 37kW connected by means of a
gearbox and controlled by a frequency converter
(VSD). Due to the criticality of the door
closing operation an emergency gearmotor of 4kW
allows the closing operation at a reduced speed
Structure
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Structure. Doors dynamics control

• Doors Dynamics Control
• Assessment of the integrated behaviour of
  structure, mechanism and control system, to
  predict malfunctions habitually caused in large
  moveable structures by interaction of these
  elements.
• A overall model representing,
• structure flexibility by means of a state-space
  model built with the modal information
• rolling resistance at the bogies by means of a
  Stribeck nonlinear friction model
• drive system represented by
• stiffness, damping and slack of the mechanical
  chain
• torque control TF, speed control PI and limiting
  power as a saturation
• -control system represented by a double PID
  position control loops
• Mechanical elements verification
• Justification of the selection of all commercial
  elements (wheels, bearings, pins, gearbox, motor,
  )
• Stress analysis of frames and tracks
• RAMS analysis

Structure
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Structure. Dome structure
Large observing slit presence of big
concentrated loads ? arch girder construction
based on three-dimensional beams forming the
primary structure and supported by a ring girder
in the base
-To transfer vertical loads to foundations and
provide the lateral stability of the dome -To
increase the stiffness in the perimeter of the
slit -To provide a stiff support for door tracks
in both open (cantilever structures) and closed
configuration -To provide a stiff interface
between the arch girders structure and the
azimuth rotation system -To provide support for
the cladding, louvers, walkways, sealing...
Structure
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Structure. Dome Azimuth Rotation System
Structure
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Structure. Dome azimuth Rotation Chamber
The azimuth rotation space is enclosed by a
thermal insulation system to prevent the heat
generated by this system to affect both the
telescope chamber environment and the enclosure
outer environment. In this chamber other elements
are allocated as the slip ring, the air seal,
hydraulic system elements (HPU, valves, piping),
frequency converters and braking resistors, etc
secondary structure cladding
access to rotating structure walkways
azimuth rotation chamber cooling system inlet
sealing brushes
slip rings
azimuth rotation chamber access panels
inflatable air seal
maintenancewalkways
sealing brushes
Structure
azimuth rotation chamber cooling system outlet
gutter
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Structure. Accessibility
Structure
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Mechanisms. Windscreen
Mechanisms
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