Frankfurt, July 19, 2016 – Lightweight design is essential for a resource-saving, energy-efficient environment. By 2020, lightweight design around the world is expected to total EUR 140 billion for the transport sector alone, with growth rates of seven to eight percent. With this in mind, VDMA has established the Working Group Hybrid Lightweight Technologies. Mechanical engineers and representatives from user and supplier industries use this platform to exchange information and ideas on opportunities, technologies and materials for lightweight design. VDMA hears from some of the experts of lightweight design in a series of interviews.
Interview with Jochen Schmidt, CEO at KARL MAYER Technische Textilien GmbH and member of the Board of the Hybrid Lightweight Technologies working group
Mr. Schmidt, how does a textile manufacturer end up in lightweight construction?
Jochen Schmidt: The requirements of fiber-reinforced plastics have risen. Injection-molded parts currently used in cars usually consist of short fibers, which are only a few millimeters long. We can use the textile to place, orient and lay up continuous fibers, thus improving component properties and saving weight. Our machines allow the customer to exert a targeted influence on the textile and thus on the fiber-reinforced component: a much stronger influence than is normally possible with an injection-molded part.
Our machines for these fiber-reinforced materials are basically an enhancement of existing machine technology. Our machines have already been used for the production of substrate materials for a very long time. When buildings are being renovated, you often see printed advertising banners covering several stories of the building. The actual force absorption takes place via a textile that is produced by our machines. This textile is then laminated or coated and then printed. Our machines for carbon fiber non-crimp fabrics are thus a further development for new applications.
What is a typical fiber composite application with your machines?
Schmidt: An important application on our machines are glass fiber non-crimp fabrics for vanes. Such a vane would be much too heavy if it were made of steel. The towers of wind turbines are most often made of steel, but the vanes are made of composite parts, in this case, fiber-reinforced plastic. If non-fiber-reinforced plastics were used, the vane could not endure the forces it is exposed to. Fibers absorb these forces. The centrifugal forces of a rotating vane are incredibly high , but the fiber non-crimp fabrics have the necessary strength.
What role does carbon play as a composite for the mechanical engineering company KARL MAYER?
Schmidt: Machines for producing non-crimp fabrics for carbon fiber composites, but also those made of glass fibers, are part of our technical textiles division. The entire division makes up about 15 to 20 percent of the KARL MAYER group. Our goal is to drive further development on the carbon market, as we see large potential here. We expect continuous growth in the carbon sector over the next few years.
KARL MAYER collaborates with the C3 project. What is this project about?
Schmidt: It is a federally supported joint project for promoting carbon-concrete composites, therefor the reinforcements made out of carbon fiber non-crimp fabrics. The carbon fiber constructions weight less and perform significantly better than normal reinforced steel when it comes to their load capacity. In addition, the lighter and still strong composite can be shaped more freely, and it does not corrode, which means that no corrosion protection is needed for the reinforcement. This enables reducing the thickness of the component by a great deal and thus the amount of concrete needed. This saves resources, as less concrete is used. It also saves large amounts of water and cement.
Do the savings balance out the higher costs of carbon?
Schmidt: If you are restoring a bridge for example, this is usually done by adding an additional layer of concrete that had been reinforced with steel mats. Using carbon in place of steel saves a great deal of weight and materials. This means that restoring the bridge can be done at the same or even lower cost. Direct application of carbon as a material is still comparatively expensive. But there are many applications in which the material savings are so substantial that it is still worth it.
There are other examples where it is worth using carbon. For example, when renovating an area where ceiling height is relevant. A renovation might not be possible at all with regular steel constructions, as too many layers would be needed and the ceiling height would no longer be sufficient. Carbon in concrete is used for high quality applications and when it is difficult to use steel for renovations.
What is your company's contribution to this project?
Schmidt: Our contribution focuses on the production of biaxial non-crimp fabric structures for reinforcing concrete parts. The biaxial fabrics have a grid structure. The load bearing carbon fiber is placed at an angle of 0 degrees as the warp and at a 90 degree angle as the weft and then is fixed with our weft knitting machines in one step. Based on this, we are also doing some fundamental research in concrete application. Thus, adaptations of this can always be derived for other materials or parts.
In which sectors do buyers deliver your machines?
Schmidt: Our customers provide numerous sectors with fabrics. Aviation remains the largest area of application for carbon, now closely followed by the automotive industry. There is considerable growth here, but carbon is also gaining importance in wind power generation. Measured against the amounts of carbon used, concrete is still a very small area of application.
Do you see further potential for the composite?
Schmidt: Whenever it is necessary to accelerate parts or to move heavy weight, it is well worth using carbon. I, for one, see great potential for carbon components in mechanical engineering in general.
What do you hope to gain from the Hybrid Lightweight Technologies working group?
Schmidt: We have in focus the use of composites, since these are exactly the components that the fabrics made with our machines are aimed at. We hope to gain more knowledge and a better connection with end users and mechanical engineering from our membership. This means we will be able to react better and faster to new requirements. This also applies to the next step, hybrid lightweight construction. Therefore we need to network in order to develop the right technology and material mix. Exchange with mechanical engineering and end users helps us greatly with this.
Germany 
