Contact development between the surfaces of two tapes is considered as a critical step in processing carbon fiber reinforced thermoplastic composites. In this study, the development of intimate contact between carbon fiber reinforced Polyamide-6 (PA-6) tapes is investigated experimentally using consolidation experiments and X-ray computed tomography for quantitative contact characterization. The experimental results indicate that the development of intimate contact occurs in the range of seconds even when temperatures are only slightly above the melting temperature and applied pressures is in the range of 1-4 kPa. Experimental data are compared with the results of the two analytical models proposed by Lee and Springer as well as Yang and Pitchumani. Both models overestimate the time needed to reach full contact for the PA-6 tape. In comparison to previously investigated PEEK materials, PA-6 has a relatively low viscosity and the tapes possess a resin-rich layer near the surface, which seems to influence the contact development process. Besides the assumptions made for viscosity, the sensitivity to input parameters describing the surface topology strongly influence the model results and the accuracy of predictions.
The topography of a surface consists of structures of different length scales. The surface roughness caused by these structures plays a decisive role in interfacial properties. Atomic Force Microscopy (AFM) can be applied to measure the surface topography with great accuracy and thus facilitates roughness quantification. Here, however, the data reduction poses a challenge. In a conventional approach, surface roughness parameters are evaluated based on averaging height differences, which leads to values dominated by the largest height differences of the surface topography. To quantify contributions of smaller structures to the roughness, a previous study presented a tunable local background correction, which eliminates structures on a larger than selected scale. Therefore, this method only considers surface structures smaller than the chosen scale. A different approach to quantify surface roughness on all length scales covered by AFM measurements uses Fourier transformation of the surface topography to calculate the power spectral density, which describes the amplitudes of different contributing spatial frequencies.In the current study, a new approach based on power spectral density is used to quantify surface roughness parameters as a function of the length scale of contributions to the surface topography. This procedure allows a comprehensive characterization of surface roughness and an intuitive comparison of different surfaces.The usefulness of this method and its compatibility to local background correction is demonstrated by analyzing several commercially available carbon fibers with and without different fiber surface treatments.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.