Lightweight construction: chances and risks

Unfortunately knowledge about fibre and structural reinforcement is increasing at as fast a pace as the multiplicity of market-ready technologies. This is a view shared by Professor Lothar Kroll, director of the Technical University of Chemnitz Institute for Lightweight Structural Construction. It is explained in part, he believes, by the massive amount of money invested in research over the last few years, necessary at the same time to get lightweight wide-bodied jets like the Airbus A380 and the Boeing 787 ‘Dreamliner’ off the ground. Professor Kroll: “The wide scope of the research has found many new ways of manufacturing composite components which are now ready to be put into practice. The automotive industry is profiting from the experience of technical applications in aviation and often is even able to follow a value-based approach – away from very expensive components towards cost-optimised designs on a large-scale production basis, that nevertheless offer outstanding mechanical strength and a very good ecological balance.”

However, to break new ground in lightweight construction will require you to look for the optimum solution to your own specific problems, which is far from easy. Having said that, many opportunities are provided by the multiplicity of mineral or vegetable oil based fibres and the even greater number of matrix materials made through synthesis or equally from sustainable resources. An example of this is the possibility of manufacturing carbon fibres both from upstream, mineral oil dependent components and also from natural fibres by way of pyrolysis. What is more, alongside isotropic carbon fibres, anisotropic fibres are also available, that modify their properties according to the direction of load force. This makes it possible to design functions into components such as load dependent deformations for example. This technological approach can be significant for development of smart blades, i.e. ‘intelligent’ rotor-blades for wind energy turbines, that modify their shape to optimise airflow, the stronger the wind blows, the greater the deformation.

Prof. Lothar Kroll heads up the non-profit making Cetex Institut für Textil- und Verarbeitungsmaschinen gemeinnützige GmbH (Cetex Institute for Textile & Processing Machines Ltd.) and is coordinator of the federal ‘cluster of excellence’ – MERGE Technologies for Multi-functional Lightweight Structures. Picture: TU Chemnitz / Kristin Schmidt

It is hard to keep track of the many and varied processing technologies used to manufacture new lightweight structures. They pose additional challenge that already requires consideration, of course, in investment terms even as the ‘foundation-stone’ of the new composite component is laid. With respect to scaling up production the manufacturers of plastics processing machines have succeeded in reducing the cycle times of fibre-reinforced components made from duroplastic reactive materials to a few minutes. At the same time the manufacturers of plastics processing machines are preparing for a future increase in the use of thermoplastic composites capable of being produced by thermoforming or on injection moulding machines. Since each production process places its own requirements on the reinforcement fibres, the fibre lengths and / or the non-woven / woven, knitted, embroidered or braided materials made from the rovings, it is essential that those with specialist know-how are consulted at an early stage.

Teijin Aramid, an exhibitor at Techtextil, is breaking new ground with carbon nanotube fibres, that offer thermal and electrical conductive properties similar to those of metals, whilst at the same time being as flexible, strong and as easy to use as textile fibres. In aviation and space flight, automotive construction, medical technology and the manufacture of functional clothing this novel combination of properties makes it possible to introduce completely new functions into the design.

No doubt therefore that the future of technical textiles will offer more than just reinforcement for matrix plastics.

Background picture: Source – TU Chemnitz / Hendrik Schmidt

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