TY - JOUR

T1 - Tensile properties of flexible composites with knitted reinforcements from various yarn materials

AU - Schwaiger, Markus

AU - Röper, Florian

AU - Wolfahrt, Markus

AU - Taesler, Johannes

AU - Schirmer, Heiko

AU - Salzmann, Moritz

AU - Feuchter, Michael

AU - Resch-Fauster, Katharina

N1 - Publisher Copyright: © 2023 The Authors. Polymer Composites published by Wiley Periodicals LLC on behalf of Society of Plastics Engineers.

PY - 2024/2/20

Y1 - 2024/2/20

N2 - 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.

AB - 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.

KW - Verbundwerkstoff

KW - flexibel

KW - Zugprüfung

UR - http://www.scopus.com/inward/record.url?scp=85178339678&partnerID=8YFLogxK

U2 - 10.1002/pc.27942

DO - 10.1002/pc.27942

M3 - Article

VL - 45.2024

SP - 2602

EP - 2614

JO - Polymer Composites

JF - Polymer Composites

SN - 1548-0569

IS - 3

ER -