Tensile properties of flexible composites with knitted reinforcements from various yarn materials

Markus Schwaiger, Florian Röper, Markus Wolfahrt, Johannes Taesler, Heiko Schirmer, Moritz Salzmann, Michael Feuchter, Katharina Resch-Fauster

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung


The tensile behavior of a flexible epoxy resin reinforced with knitted reinforcements from various fiber materials was comprehensively studied in the wale and course direction. By measuring dry yarns, temperature‐treated yarns, dry knitted fabrics and flexible composites, the effect of the fiber material and the knitted fabric on the tensile properties was analyzed. The interlock knit structure strongly affected the deformation behavior of the flexible composites which differed significantly from the dry knitted fabrics. The deformation behavior of the flexible composites was monitored using digital image correlation which revealed the formation of cracks and high local strain differences in the course direction for all fiber materials. This was linked to fiber‐matrix debonding by scanning electron microscope observations. In the wale direction, the deformation of the knitted structure under tensile load led to plastic deformation of the matrix material. Overall, with yarns from recycled thermoplastic fibers, a higher maximum stress and strain at break was achieved compared to bio‐based fibers. However, irreversible damage occurred for all fiber materials at similar strain values. Highlights Tensile tests on yarns, knitted fabrics and flexible composites. Investigation of the effect of fiber material on mechanical properties. High local strain differences in composites due to knitted structure. Fiber‐matrix debonding in course direction. Plastic deformation of the matrix material in the wale direction.
Seiten (von - bis)2602-2614
FachzeitschriftPolymer Composites
Frühes Online-Datum27 Nov. 2023
PublikationsstatusVeröffentlicht - 20 Feb. 2024

Bibliographische Notiz

Funding Information:
The research project is funded by the Austrian Ministry for Climate Action, Environment, Energy, Mobility, Innovation and Technology in frame of the program “Produktion der Zukunft” under contract no. 871403, within the context of the project “Semiflexible and flexible composites based on renewable resources”. Special thanks go to Sebastian Maar for testing of the yarns and knitted fabrics. The funding of the Montanuniversitaet Leoben for Open Access publishing is gratefully acknowledged.

Publisher Copyright:
© 2023 The Authors. Polymer Composites published by Wiley Periodicals LLC on behalf of Society of Plastics Engineers.


  • Verbundwerkstoff
  • flexibel
  • Zugprüfung

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