Textile-integrated carbon filament yarn sensors for structural health monitoring of membranes and composites: Fid-Bau Portal

Textile-integrated carbon filament yarn sensors for structural health monitoring of membranes and composites

Häntzsche, Eric / Bardl, Georg / Nocke, Andreas / Cherif, Chokri

Short notice given only substantially as follows: The structural health monitoring of large-scaled fiber-reinforced composite components, as well as the monitoring of textile-based membranes for a large-range application spectrum, plays a crucial role for the further advancement of lightweight design approaches. It is only through structurally integrated condition monitoring systems, that damages can be detected early on, thus enabling the possibility of local repairs before complete structural failure occurs. Therewith, idle periods of machinery and plants can be significantly decreased or even avoided. The potential of carbon filament yarns (CFY) acting as basic-material for two-dimensional integrated strain sensors in thermoplastic composites has been shown in previous investigations. Using the CFYs' piezo-resitive effect, means the mapping of every structural stresses on a measureable electrical carrier signal, an increasing strain can be calculated and visualized due to an increasing resistance of the carbon filaments. This contribution presents current research activities aimed at the textile-technically integration of CFY sensors into single-layer-woven as well as non-crimp fabrics for architectural membrane applications and composite applications respectivly. For the integration of the textile-based sensors, two integral manufacturing processes are applied: the integration into multiaxial non-crimp fabric structures during the warp knitting process is done through a warp yarn shogging device, which offers the possibility to move individual CFY bands over the fabric's width. With suchlike manufactured semi-finished reinforcement structures, a functional model of a small wind turbine blade in glass-fiber epoxy composite design has been build up using RTM technique. For the superficial embedding of CFYs onto single-layer woven structures, a multiaxial weaving machine with LINDAUER DORNIER'S Open Reed Weave (ORW) technology and lateral shogging device for additional CFY warps is used, thus allowing the manufacturing of textile sensors with custom two-dimensional layouts during the weaving process. With this approach, in-situ sensor systems within the load-transferring areas of the membrane and with a high sensor protection can be provided, allowing a continuous and nondestructive structure- and load-monitoring of limp constructions, e.g. floating domes or even foil hoods for biogas storage facilities. Based on two functional models, the potential of the ORW weaving and warp knitting technique in combination with warp shogging devices and of the realizable sensor structures are presented as well. Further research steps aiming at the electro-mechanical behaviour of the sensors under static and dynamic loads and at the long-term stability of its electrical contact points are presented.