Relevance of deconsolidation on the porosity of thermoplastic CFRP tubes wound with direct electrical resistance heating

Abstract

Continuous Resistance Heating Technology (CoRe HeaT) uses Joule heating to melt carbon fibre reinforced thermoplastic tapes during automated fibre placement (AFP) or winding, enabling higher deposition rates and improved productivity. Heating of thermoplastic carbon fibre (CF) material causes deconsolidation, voids and release of internal stresses. The extreme heating rates that can be achieved with Joule heating and the challenges with temperature homogeneity that come along, are other factors that can play a role in that regard. The study employs static tests and a CoRe HeaT-assisted winding machine, analysing micrographs with a machine learning-based semantic segmentation model to detect voids. Results show wound tubes have interlaminar voids rather than intralaminar ones, indicating deconsolidation has limited effect on overall porosity. Thus, optimizing compaction at the nip point is crucial for defect-free preforms.