Composites and Sustainability

This project, funded by the DFG, aims to qualify the use of staple fiber yarns made from recycled carbon fibers (rCF-SF) for the production of organic sheets and their behavior in the thermoforming process.

In this DFG project, rCF-SF tapes are produced from staple fiber yarns in a laboratory test rig with in-line-quality acquisition. The tapes are further processed into organo sheets in the tape laying process including improving of the single fiber orientation and finally post-consolidated in the autoclave. Subsequently, the influence of the process parameters on the resulting mean fiber orientation is determined and corresponding algorithms for the process regulation and the process control are derived. Due to the finite fiber length, the staple fibers offer the potential to slide against each other after the melting temperature of the matrix polymer is exceeded. The staple fibers thus enable a pseudo-plastic material behavior in the thermoforming process. In the tensile test, the staple fiber organo sheets are analyzed in detail with regard to their pseudo-plastic material behavior and the description model for the process behavior in the thermoforming process is calibrated. The results of the 1D tensile tests on the pseudo-plastic deformation behavior are transferred to the 2D thermoforming process and the calibrated description model is used for the simulation of the 2D-thermoforming process. The continuous digital recording of process variables allows linking the correlation between input (yarn properties, process parameters) and output variables (tape properties, preform properties).