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Ultraviolet Light Makes "Impossible" Shapes from Composite Materials

Gordon Smith Demonstrates the Technology
Gordon Smith Demonstrates the Technology
Originally published 15 March 1999

Researchers at the Warwick Manufacturing Group, part of the University of Warwick, have developed a way of creating composite materials with shapes that have previously been impossible. The research enables materials reinforced with glass fibre to find new uses in cars and construction - it could even pave the way for making composites in space.

Composite materials, with their ability to deliver lightweight materials tailored to meet particular needs, could have many uses but handling and assembly of materials with different properties to create composites brings drawbacks as well as benefits particularly in processing techniques. One obstacle with composites has been the difficulty of joining materials. This makes it hard to create complex shapes.

Warwick researchers David Britnell and Gordon Smith have developed a process which avoids this drawback with a technique that eliminates the need to use corner joints for complex shapes.

By adapting pultrusion techniques, the researchers can create fibre-reinforced components in complex shapes. Two advances made this possible: the use of ultraviolet light rather than heat to cure the resin coated fibres; and manipulation of the pultruded composite shape by a computer controlled robot.

Dr Smith’s first idea to was to heat the materials with a laser but found that a focused ultraviolet source provided the energy needed to cure the composite. Pultrusion usually relies on pulling resin coated fibres through a long heated die. The die shapes the material, creating continuous shapes, such as round bars, angles or rectangular hollow sections. The heat from the die cures the resin as the composite forms - but by using pultrusion and UV light rather than heat from a die to cure the resin, they have increased the range of shapes that are open to composites. “You can do extremely complicated shapes, for example window frames without a joint”, says Dr Smith.

As well as its ability to create new shapes, the technology also allows manipulation of the fibres emerging from a die eg:- twisting the fibres during the heating stage to strengthen the composite.

The researchers believe that their work could benefit many industries. In cars the composites could be an alternative to steel and aluminium in space frames. In concrete, fibre composites could substitute for steel reinforcement where corrosion is a hazard. In space it might be possible to produce materials that could be processed in orbit - in space the Sun might even provide the energy to cure the resins.

For further information please contact:

Dr Gordon Smith, Warwick Manufacturing Group,
University of Warwick Tel: 024 76 523784