23 July 2006
23 July 2006
The performance and productivity achievable with 3D composite reinforcement technologies are driving demand and stimulating development in the aerospace sector, and a UK team has been discovering the advances being made in the US.
A team from UK organisations was brought together to undertake a Department of Trade and Industry (DTI) Global Watch Mission to the USA to find out about the modelling and manufacturing developments that are getting advances off the ground in the US.
High-performance composites are already a mainstay of aerospace components and secondary structures, but over the next decade the industry intends to use even more advanced techniques for primary structures such as fuselages and wings. The challenge for suppliers is to develop 3D weaving, knitting and braiding processes capable of delivering the complex shapes and cost reductions required. These techniques give control over fibre orientation and architecture to produce fully integrated 3D net-shaped preforms with variable properties, and when fully automated they can dramatically improve efficiency.
‘Recent manufacturing advances have made 3D composite structures much more of a commercial possibility, but manufacturers now need to know much more about the performance and tolerances required by end users,’ says Sue Panteny, representing the National Composites Network, which co-ordinated the mission. During visits to 3D composite reinforcement manufacturers and research organisations in New England, Pennsylvania, Delaware and North Carolina, the team of UK experts asked questions about novel machinery and modelling tools which are beginning to provide some key answers for suppliers and users.
According to the team, representing Airbus, Carr Reinforcements, Nottingham University, Parkhill Textiles, Rolls-Royce, Saint-Gobain Technical Fabrics, Bombardier Aerospace UK and the University of Ulster, technical capabilities might be similar on both sides of the Atlantic but exploitation experience is much greater in the US. ‘We were shown a near net-shaped preform for an engine fan blade which demonstrates that they are starting to develop real components and the real potential of 3D weaving for aerospace and beyond,’ says Professor Robert McIlhagger of the University of Ulster and Bombardier Aerospace UK.
Next-generation weaving at Bally Ribbon Mills
This Pennsylvanian ribbonmaker has diversified into the woven carbon fibre market on a large scale with great determination and significant funding. The five-axis weaving machine it has developed was one of the highlights of the mission. ‘For normal weaving of a flat – so-called 2D – piece of fabric you have warp and weft threads at right angles,’ says Professor Robert McIlhagger. ‘With a five-axis machine you have the warp and weft – x and y – directions but also a z direction which gives a consolidated woven structure with the ability to weave fibres into the structure at 45 degrees, taking weaving to the next level.’
Predictive modelling at 3Tex
Spun out of North Carolina State University to commercialise technologies developed in the Mechanical and Aerospace Engineering department, 3 Tex demonstrated an impressive array of expertise. ‘3 Tex has a considerable academic capability which is being used to advance its understanding of the influence of reinforcement architectures on component structures,’ says Lee Bateup of Saint-Gobain Technical Fabrics. ‘Through modelling it is gaining knowledge that will enable more precise specification and more appropriate products.’ 3 Tex has also developed 3D weaving and braiding techniques, the latter offering greater flexibility and a smart way of making hollow parts. According to Professor Andrew Long, of Nottingham University, this combination of capabilities puts the company in a strong position: ‘It is able to look at a component, talk about requirements and, as it has a strong interest in two alternative processes, recommend the right one.’
The team gained an insight into where 3D composites might go in the future at the Massachusetts Institute of Technology and the University of Delaware. The former has grown carbon nanotubes onto fibres which, if reproduced on layers of carbon fibre fabric, could make an innovative 3D material in a very usable form. Delaware, meanwhile, is investigating how the blast-resistance of some 3D woven materials could be used in military applications such as ballistics, hard armour and vehicle structures.
Five reasons to use 3D fabrics
The advantages of using complex preform shapes made using 3D weaving processes rather than fabrics made by traditional fabric cutting and layering fabrication methods include:
The image shows 3-D weaving, courtesy of 3TEX Inc. This article originally appeared in Global Watch, the monthly magazine of the DTI Global Watch Service. For further information on Global Watch please follow the link below; a link to the full report is also provided.
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