Deformation Behavior of Staple Fiber Organo Sheets

This DFG funded project investigates the processing of staple fiber yarns made from recycled carbon fibers (rCF-SF) to organo sheets and the characterization of their pseudo-plastic deformation behavior in thermo-forming experiments.

In the first project phase, rCF-SF consisting of rCF and PA6 were processed into staple fiber tapes (SF tapes) by using a modified calendaring process being developed at IVW. In the calendering unit, the SF yarns are heated above the polymer’s melting temperature and stretched by a speed difference between
the preconsolidation rolls and the consolidation rolls, thereby improving fiber orientation. The influence of total stretching, temperature and number of machine passes on the tape geometry, the resulting fiber orientation and the mechanical properties were investigated to determine optimum process parameters. During further work, additional stretching will be applied to the SF-tape in the tapelaying process. The resulting impact on fiber orientation and mechanical properties will be quantified subsequently. In the second project phase, SF organo sheets will be tested in temperature controlled tensile tests to evaluate their pseudo-plastic deformation behavior. For this purpose, a test module will be developed to reconsolidate it after finalizing the tensile test. To determine the influences on pseudoplastic deformation behavior, parameters such as process speed, tempera-ture and SF-tape total stretching are analyzed. Based on these findings, a description model for the thermoforming process behavior will be calibrated and subsequently validated. The project goal is to develop an innovative process chain from staple fiber yarn to the finished component. At the same time, a comprehensive understanding for the pseudo-plastic deformation behavior during thermoforming needs to be established.