Intrinsically controlled carbon fiber composites by exploiting electrical properties

• Applicant: Professor Dr.-Ing. Markus Böl
• Subject Area: Plastics Engineering ; Lightweight Construction, Textile Technology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 553258609

The basic idea of the research project is based on the electrical conductivity of carbon fibers and their change in resistance when stretched. With this "self-sensing" approach, a possibility for complete sensor integration in fiber composite structures is pursued. Since the integrated sensor and the surrounding component are made of the same material, this approach can minimize negative effects of the sensor on the mechanical properties of the material due to different Young's moduli or coefficients of expansion. As a manufacturing process for sensors made of carbon fiber-reinforced plastic (CFRP), the pultrusion process in particular is being investigated in this research project, as it enables the cost-effective production of sensors of almost any length. This is particularly interesting for use in very large components, such as CFRP chords of rotor blades for wind turbines. Elongation of the sensor in the longitudinal direction leads to a change in resistance. This phenomenon enables the use of CFRP for load monitoring of structures. For piezoresistive sensors, the k-factor describes the sensitivity of the sensor and represents the relationship between the normalized resistance change and strain. Literature research indicates that the k-factor of carbon fibers is about 2, which is the same as conventional strain gauges, so these sensors are promising for load monitoring of structures. Integrated structure monitoring can reduce the need for costly inspections, thereby reducing downtime and costs. Other conceivable applications include monitoring bridges or elevator ropes.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr.-Ing. Michael Sinapius