Imagine self healing of a scratch on a plastic trim part of an automobile. What sounds like a dream could turn into a reality soon. While some people enthuse about the ‘steel of the 21st century’, others warn against expecting too much from the use of carbon fibre materials in large-scale motor vehicle production for reasons of technology and cost. While proponents provide proof of feasibility with automotive bodies manufactured entirely from carbon fibre reinforced plastic and/or individual bumper beam or tailgate components made from this miracle material with the high-tech image, the devotees of conventional materials tend to be dismissive. They find the miracle material too expensive, not suitable for large-scale production, and too difficult to recycle. Nevertheless both sides are aware that textile research institutes have had encouraging research successes.
As the search for light weighting moves forward, it provides fodder for strategy debates. An outcome of these debates, followed by research and development is leading to more and more innovations in carbon fibre reinforced plastic components. For example, automotive engineers are saying good-bye to the simple bonnet plate in the wake of researchers in textiles having come up with a proposal for an improved pedestrian collision protector in the form of an intelligent bonnet. In the Dresden-based ITM working in co-operation with the Aachen Institutes for Textile Technology (ITA) and Motor Vehicles (ika) an integrated passive protection has been developed from textile spacer materials and incorporated in the bonnet of the Volkswagen ‘Golf V’. In addition to its mechanical function this insulating 3D structure has acoustic and thermal properties, and is intended to absorb the impact of the collision between man and machine in such a way that the heady injury criterion (HIC) values, critical for survival, are met in line with EU regulations. Textile research is also looking in other directions. One example is fibre composite materials that help components to repair any damage themselves.
Just as the human body gradually heals itself following an injury, certain fibre composite materials are cable of regeneration after they become damaged. According to researchers at the Institute for Textile Chemistry and Chemical Fibres (ITCF) in Denkendorf, Germany, innovative new composites should restore their original material properties after a small crash for instance. It is said that special polymer technologies have already been able to achieve up to 30 continuous repair cycles – either independently or induced through UV light or heat. In addition self-healing materials enable totally new safety features; they could help to maintain, and/or restore the functionality of tyres and windscreens.
One decisive factor for the development is the speed at which research is transferred to industry. One example of this development is the topic of manufacturing reproducible pre-forms. The parties involved in the research being Institute of Textile Machinery and High Performance Material Technology (ITM) of the Technical University of Dresden, Germany. Also, the engine builder topcut bullmer GmbH from Mehrstetten (Baden-W?rttemberg), Germany. Topcut bullmer specialises in the handling of pliable materials, and has an experience in the field dating back to 80 years. Collaboration between research institute and small business has developed automated spreading concepts to apply adhesive locally for the production of pre-forms, setting a further efficiency principle for the mass production of fibre composite structures. The core task was to establish a CNC controlled automated process chain including laying, spraying and cutting technology for multi-ply fabrics that need to be laid down without creasing as a single layer or stacked for further processing on, or in the form of the finished component.
Another example is the automated drapability tester. When manufacturing fibre composite components, the drapability (ability of reinforcement textiles to adapt to the three dimensional form of the component contours specified in the design) plays a decisive role. Anyone wanting to undertake large-scale production of high-precision, fibre-based semi-finished products in qualities that are reproducible requires, amongst other things, a standardised test methodology to characterise the drapability. Previous manufacturing parameter investigations by the Institute for Textile Technology of the RWTH University of Aachen, Germany, in terms of their effect on the spherical formability of materials were taken up by Textechno Herbert Stein GmbH, based in M?nchengladbach, on the basis of ‘ZIM’ Central Innovation Programme, and in the space of only a year and a half had been incorporated in a test device that is so far the only one of its kind in the world. The ‘DRAPETEST’ is now mass produced and makes it possible to identify qualitative draping errors in non-woven and woven fabrics.
Leave a Reply