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Article
Publication date: 16 October 2018

Özgür Keleş, Eric H. Anderson and Jimmy Huynh

Mechanical reliability (variations in mechanical properties) of fused deposition modeled (FDMed) short-fiber-reinforced composites are unknown, which limits wider and safer use of…

Abstract

Purpose

Mechanical reliability (variations in mechanical properties) of fused deposition modeled (FDMed) short-fiber-reinforced composites are unknown, which limits wider and safer use of these composites. Accordingly, this paper aims to investigate the mechanical reliability of FDMed model material short-carbon-fiber-reinforced acrylonitrile butadiene styrene (SCFR-ABS). A new vibration-assisted FDM (VA-FDM) process was used to reduce porosity.

Design/methodology/approach

Tensile tests were performed on FDMed SCFR-ABS produced with and without vibrations. Weibull analysis was performed to quantify the variation in fracture strength, tensile strength, strain at break and strain at tensile strength.

Findings

Introduction of vibrations to the extrusion head during FDM decreased the inter-bead porosity in SCFR-ABS and thus improved elastic modulus, toughness, fracture strength, tensile strength and strain at break. Weibull modulus of fracture strength increased from 25 to 57 with vibrations.

Practical implications

The reported Weibull analysis offers a practical design guideline to predict failure rates at specific service stresses.

Originality/value

A detailed Weibull analysis of the variations in the mechanical properties of FDMed SCFR-ABS was performed for the first time. A new vibration-assisted FDM process was reported to reduce inter-bead porosity in FDMed composites.

Details

Rapid Prototyping Journal, vol. 24 no. 9
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 10 July 2021

Stephanie S. Luke, David Soares, Janaye V. Marshall, James Sheddden and Özgür Keleş

Fused filament fabrication of continuous-fiber-reinforced polymers is a promising technique to achieve customized high-performance composites. However, the off-axis tensile…

Abstract

Purpose

Fused filament fabrication of continuous-fiber-reinforced polymers is a promising technique to achieve customized high-performance composites. However, the off-axis tensile strength (TS) and Mode I fracture toughness of fused filament fabricated (FFFed) continuous-glass-fiber-reinforced (CGFR) nylon are unknown. The purpose of this paper is to investigate the mechanical and fracture behavior of FFFed CGFR nylon with various fiber content and off-axis fiber alignment.

Design/methodology/approach

Tensile tests were performed on FFFed CGFR-nylon with 9.5, 18.9 and 28.4 fiber vol. %. TS was tested with fiber orientations between 0 and 90 at 15 intervals. Double cantilever beam tests were performed to reveal the Mode I fracture toughness of FFFed composites.

Findings

TS increased with increasing fiber vol. % from 122 MPa at 9.5 vol. % to 291 MPa at 28 vol. %. FFFed nylon with a triangular infill resulted in 37 vol. % porosity and a TS of 12 MPa. Composite samples had 11–12 vol. % porosity. TS decreased by 78% from 291 MPa to 64 MPa for a change in fiber angle θ from 0 (parallel to the tensile stress) to 15. TS was between 27 and 17 MPa for 300 < θ < 900. Mode I fracture toughness of all the composites were lower than ∼332 J/m2.

Practical implications

Practical applications of FFFed continuous-fiber-reinforced (CFR) nylon should be limited to designs where tensile stresses align within 15 of the fiber orientation. Interlayer fracture toughness of FFFed CFR composites should be confirmed for product designs that operate under Mode I loading.

Originality/value

To the best of the authors’ knowledge, this is the first study showing the effects of fiber orientation on the mechanical behavior and effects of the fiber content on the Mode I fracture toughness of FFFed CGFR nylon.

Details

Rapid Prototyping Journal, vol. 27 no. 7
Type: Research Article
ISSN: 1355-2546

Keywords

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