DFG-SFOB – Process analysis of pseudo-plastic behavior of unidirectional reinforced staple fiber organic sheets

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The project "Process analysis of the pseudo-plastic deformation behavior of unidirectionally reinforced staple fiber organic sheets" aims to use an innovative process chain to use staple fiber yarns made from recycled carbon fibers (rCF-SF) for the production of unidirectionally reinforced organic sheets. The aim is both to recycle CF primary waste and to open up new fields of application through the pseudo-plastic deformation behavior of rCF-SF during thermoforming.

In this project, staple fiber yarns made of recycled carbon fibers (rCF) and PA6 fibers were produced by Wagenfelder Spinnerei GmbH and then processed into semi-finished tape products at IVW using a modified impregnation and calendaring process. The influence of the process parameters (temperature, process speed and stretching) on the mechanical properties as well as on the macroscopic (width and thickness) and microscopic properties (fiber orientation and impregnation) was investigated.

The rCF-SF tapes produced were then further processed into tape preforms in an automated tape laying process (7 NL/min). These tape preforms were processed into organic sheets in an autoclave (25 min. holding time at a target temperature of 265 °C at 25 bar pressure, total process time 118 min.) and then tested for their pseudo-plastic deformation behavior using a newly developed test setup. This test setup enabled local, homogeneous heating of the tensile specimens in the loaded area. After reaching the target temperature, a high-speed tensile test was carried out, followed by reconsolidation of the specimens. To analyze the pseudo-plastic behavior, various process parameters, including test speed, test temperature and the total elongation of the SF tapes, were systematically varied. The results obtained serve as the basis for the development of a simulation model that enables a precise description of the process behavior during thermoforming, which is then validated in real thermoforming tests.

The project "Process analysis of the pseudo-plastic deformation behavior of unidirectional reinforced staple fiber organic sheets" is funded by the German Research Foundation (DFG) - funding code 471480678.

Reconsolidated sample after the temperature-controlled tensile test

Test module for temperature-controlled tensile tests

Contact

M.Sc.

Martin Detzel

Scientific Staff Remanufacturing & Repair

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