In-plane Shear Properties of High-Performance Filaments

Slusarksi, K. A.; Walter, Matthew S.; Bogetti, Travis A.; Wetzel, Eric D.

doi:10.1007/978-3-319-00765-6_14

Cited by 3 publications

(2 citation statements)

References 11 publications

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“…However, the methodology entails a large experimental scatter owing to the uncertainty in the determination of the exact defect size that caused the failure and the maximum stress attained during the experiments. The focused ion beam (FIB) opens revolutionary opportunities for testing materials at the microlevel by selective removing/carving material and generating complex geometries suitable for testing [1,2].…”

Section: Introductionmentioning

confidence: 99%

Strength and toughness of structural fibres for composite material reinforcement

Herráez

Fernández

Lopes

et al. 2016

Phil. Trans. R. Soc. A.

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The characterization of the strength and fracture toughness of three common structural fibres, E-glass, AS4 carbon and Kevlar KM2, is presented in this work. The notched specimens were prepared by means of selective carving of individual fibres by means of the focused ion beam. A straight-fronted edge notch was introduced in a plane perpendicular to the fibre axis, with the relative notch depth being a 0 / D ≈0.1 and the notch radius at the tip approximately 50 nm. The selection of the appropriate beam current during milling operations was performed to avoid to as much as possible any microstructural changes owing to ion impingement. Both notched and un-notched fibres were submitted to uniaxial tensile tests up to failure. The strength of the un-notched fibres was characterized in terms of the Weibull statistics, whereas the residual strength of the notched fibres was used to determine their apparent toughness. To this end, the stress intensity factor of a fronted edge crack was computed by means of the finite-element method for different crack lengths. The experimental results agreed with those reported in the literature for polyacrylonitrile-based carbon fibres obtained by using similar techniques. After mechanical testing, the fracture surface of the fibres was analysed to ascertain the failure mechanisms. It was found that AS4 carbon and E-glass fibres presented the lower toughness with fracture surfaces perpendicular to the fibre axis, emanating from the notch tip. The fractured region of Kevlar KM2 fibres extended along the fibre and showed large permanent deformation, which explains their higher degree of toughness when compared with carbon and glass fibres. This article is part of the themed issue ‘Multiscale modelling of the structural integrity of composite materials’.

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Section: Introductionmentioning

confidence: 99%

Strength and toughness of structural fibres for composite material reinforcement

Herráez

Fernández

Lopes

et al. 2016

Phil. Trans. R. Soc. A.

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“…It is well suited for research efforts where only a small number of fibers may be available and can unveil key insights into the microstructure-property relationships governing the CF performance through inspection of pores, inclusions, and other irregularities in the fiber fracture surface [6]. Alternative methods, such as atomic force microscopy, nanoindentation, and picosecond ultrasonics, have been proposed but have not gained widespread adoption [5,[7][8][9]. ASTM C1557-20 is the most widely used method for tensile testing single fibers to determine their tensile strength, strain at break, and Young's modulus [10].…”

Section: Introductionmentioning

confidence: 99%

Analyzing the effect of misalignment on single-filament carbon fiber tensile testing via stereoscopic computer vision imaging

Love-Baker

Harrell

Brown

et al. 2021

Meas. Sci. Technol.

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An understanding of the constitutive properties of carbon fibers (CFs) is critical to the accuracy of high-resolution composite simulations and to the development of CF derived from low-cost alternative precursor materials. Single-fiber tensile testing is a capable tool to measure CF properties and is well suited to research efforts where only a small number of fibers may be available. However, single-fiber tensile tests are challenging to conduct due to the difficulty in handling small diameter fibers (5–15 μm), the brittleness of single fibers, and the required nanoscale/microscale resolution of testing equipment. The accuracy of the measured properties depends on several factors, but a critical factor is fiber misalignment, especially at short gauge lengths. Current standards do not address the effect of tensile specimen misalignment on measured properties. This work presents a robust method of fiber alignment using stereoscopic computer vision that enables users to align fibers vertically for tensile testing to improve the accuracy of resulting mechanical properties. Additionally, an analytical relationship between fiber misalignment angle and measured properties is developed and validated against the experimental results. As a result, new best practices for single-fiber tensile testing of CF are recommended.

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