Filament winding Fibre placement Tape laying Pultrusion Tube rolling

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Filament windingFibre placementTape
layingPultrusionTube rolling

• John Summerscales

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Filament winding

• continuous fibre reinforcements are precisely
  positioned in a pre-determined pattern on a
  rotating mandrel (mould tool for filament
  winding)
• normally computer numerically controlled (CNC)
  to permit highly automated production of
  axisymmetric components

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Filament winding

• simple machine just two axes
• rotation of the mandrel
• translation of the feed eye on an axis parallel
  to the machine axis
• complexity characterised bythe number of degrees
  of freedom
• up to six separately controlled axes
• usually three orthogonal and three rotational axes

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Filament winding

• image from http//www.tifac.org.in/news/acfil.jpg

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Filament winding - tension

• fibre tension is critical to the operation of a
  filament winding machine
• normal to have fibre tensioners(closed-loop
  controlled servo-driven "dancers")
• tension required depends on
• type of fibre
• part diameter
• winding pattern

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Filament winding - tension

• fibre tension directly affects
• fibre volume fraction
• void content
• and, in turn, influences the strength and
  stiffness of the composite part.
• difficult to maintain tension on flat surfaces
• axial winding not a preferred orientation on
  cylinders.

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Filament winding - impregnation

• resin impregnation

image from http//www.pultrex.com/images/productim
ages/resin2.jpg
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Filament winding - winding patterns

• hoop (90º) a.k.a girth or circumferential winding
• angle is normally just below 90 degrees
• each complete rotation of the mandrel shifts the
  fibre band to lie alongside the previous band.
• helical
• complete fibre coverage without the bandhaving
  to lie adjacent to that previously laid.
• polar
• domed ends or spherical components
• fibres constrained by bosses on each pole of the
  component.
• axial (0º)
• beware difficult to maintain fibre tension

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Filament winding - winding patterns

• hoop helical
• polar
• images from
• http//www.tifac.org.in/news/acfil1.jpg
• http//www.tifac.org.in/news/acfil2.jpg
• http//www.tifac.org.in/news/acfil3.jpg

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Filament winding - winding pattern

• Kevlar component

image from http//www.tifac.org.in/news/acfil5.jpg
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Filament winding - geodesic path

• simplest fibre orientation is the geodesic path
• assumes non-slip winding
• once winding has commenced,fixed fibre path at
  any point dictated by the Clairaut angle ( r.sin
  a constant)
• where r is local radius, a is local angle
• at bosses, a arcsin (rb/r)
• where rb angle at the boss (polar opening)
• exploiting friction, it is possible to achieve
  non-geodesic winding within limits.

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Lattice structures (anisogrid)

• can be produced by partial coverage and careful
  choice of relative band positions

image from Vasiliev et al, Composite Structures,
2001, 54(2-3).
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Filament winding - applications

• pressure vessels, storage tanks and pipes
• rocket motors, launch tubes
• Light Anti-armour Weapon (LAW)
• Hunting Engineering made a nesting pair in 4
  minuteswith 20 mandrels circulated through the
  machineand a continuous curing oven.
• drive shafts
• Entec the worlds largest five-axis filament
  winding machine for wind turbine blades
• length 45.7 m, diameter 8.2 m, weight gt 36
  tonnes.

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Fibre placement

• multi-axis robot wet-winds fibrearound a series
  of pins(or similar restraints within a mould)in
  a predetermined pattern.
• not limited by geodesic paths
• used to produce Geoform(lattice-work with
  coverage in specific bands)
• better for thermoplastic matrix composites
• on-line consolidation and cooling permit use
  without the requirement for the fibre restraints.

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Tape laying

• computer-numerically controlled (CNC) technique
  laying prepreg reinforcement tape
• Cartesian framework for gross positioning(rather
  than a primarily rotational axis robot)
• rotational freedoms close to the work-piece.
• used for thermoset or thermoplastic matrix
• limited to flat or low curvature surfaces
• high quality aerospace compositese.g. flight
  control surfaces and wing skins.

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Pultrusion

• continuous constant cross-section profile
• normally thermoset (thermoplastic possible)
• impregnate with resin
• pull through a heated die
• resin shrinkage reduces friction in the die
• polyester easier to process than epoxy
• tension control as in filament winding
• post-die, profile air-cooled before gripped
• hand-over-hand hydraulic clamps
• conveyor belt/caterpillar track systems.
• moving cut-off machine ("flying cutter")

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Pultrusion

• production of constant cross-section profiles

Image from http//www.acmanet.org/pic/images/schem
atic.jpg
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Pultrusion - design

• manuals by Quinn and Hartley
• seek uniform thickness in order to achieve
  uniform coolingand hence minimise residual
  stress.
• hollow profiles require a cantilevered mandrel to
  enter the die from the fibre-feed end.

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Pultrusion -applications

• panels beams gratings ladders
• tool handles - ski poles kites
• electrical insulators and enclosures
• light poles - hand rails roll-up doors
• 450 km of cable trays in the Channel Tunnel
• plus ...

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Pultrusion (ACCS/Composolite)

• Advanced Composite Construction System
• components plank ............... and connectors
• used in Aberfeldy and Bonds Mill Lock bridges
• http//www.ksci.com/graphics/aberf.gif and
  http//www.stroudwater.co.uk/cpsn/bonds20mill20b
  ridge203.jpg

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Pultrusion - variations of process

• pulwinding/pulbraidingfibres are wound onto the
  core of the pultrusion before it enters the
  heated die.
• pulformingthe profile is subjected to post-die
  shaping.

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Tube rolling

• a technique where pre-preg isformed onto a
  tapered mandreland consolidated using
  shrink-wrap.
• most often used to make fishing rod blanks
• illustrated athttp//www.kilwellfibretube.co.nz/b
  lank-making.html