A study of the effect of experimental test parameters on data scatter in microbond testing

Pandey, Gajendra; Kareliya, Chirag Himmatbhai; Singh, Raman P.

doi:10.1177/0021998311410508

Cited by 25 publications

(23 citation statements)

References 21 publications

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“…The average IFSS, Τ ave , is calculated as the experimental peak force divided by the contact surface area at the interface, assuming the stress distribution is uniform over the interface. 21,26 Alternatively, the ultimate IFSS, Τ ult , is the shear stress at the point where interfacial failure initiates. 27 The value of Τ ult can be determined from Raman spectroscopy 27 by evaluating local strains in specimens at the fibre/matrix interface, 15 but these experiments are difficult to perform compared to the microdroplet test.…”

Section: Fe Modelling For Microdroplet Testmentioning

confidence: 99%

“…In addition, the contact point of the blades on the droplet is expected to influence the stress distribution at the interface, affecting the failure mode and the IFSS. 20,21 The FE model is used to study the effect of the radial opening distance between the shear blades, and the axial misalignment of the blades, which can occur due to inaccurate experimental setup. 22,23 The meniscus that forms where the fibre exits the droplet is neglected in some FE models in the literature.…”

Section: Introductionmentioning

confidence: 99%

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Finite element study of the microdroplet test for interfacial shear strength: Effects of geometric parameters for a carbon fibre/epoxy system

Zhao

Qian

Harper

et al. 2017

Journal of Composite Materials

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A 3D finite element model has been developed to identify the main causes of variability in the microdroplet test, which is commonly used to characterise the interfacial shear strength between polymer matrices and single filaments. A more realistic droplet shape and test configuration, including meniscus details and prismatic shear blades, have been modelled for a carbon fibre/epoxy system to simulate a more representative set up than is commonly used in the literature. The interfacial behaviour has been modelled using a cohesive surface contact and fibre breakage has been captured using a maximum stress criterion. A statistical study has been performed to systematically evaluate the influence of key geometrical test parameters on the variability in the measured interfacial shear strength values and the likelihood of fibre breakage. Parameters studied are fibre embedded length, fibre diameter, shear blade radial opening distance and shear blade axial misalignment. Results of the studied carbon fibre /epoxy system suggest that fibre embedded length and the combined effects of the shear blade radial distance and the shear blade axial misalignment are the most significant sources of variability for the measured interfacial shear strength. However, fibre embedded length and the shear blade radial distance are the most significant variables contributing to fibre breakage.

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Section: Fe Modelling For Microdroplet Testmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Finite element study of the microdroplet test for interfacial shear strength: Effects of geometric parameters for a carbon fibre/epoxy system

Zhao

Qian

Harper

et al. 2017

Journal of Composite Materials

View full text Add to dashboard Cite

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“…The deformation associated with debonding is assumed to be elastic, although some authors have noted that plastic deformation can occur for thermoplastic systems [31], potentially invalidating results. The calculation for apparent IFSS also assumes that the stress along the interface is constant, which is a simplification, as the shear-lag approach [32,33] and FEA modelling [34,35] have both shown it varies along the embedded length. A constant interfacial stress also implies that failure is more sudden, with no account for the progressive ''unzipping'' due to interfacial crack propagation.…”

Section: Microbond Testmentioning

confidence: 99%

The usability of recycled carbon fibres in short fibre thermoplastics: interfacial properties

et al. 2016

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The objective of this study was to investigate the feasibility of combining discontinuous recycled carbon fibres with polypropylene, to produce a low-cost, high specific stiffness material for high-volume applications. The inherent low affinity of carbon fibre and polypropylene motivated a detailed study of the surface characteristics of carbon fibre and interfacial behaviour between the two materials, using the microbond test. The effects of removing the sizing from the fibres, as well as introducing a maleic anhydride-grafted polypropylene coupling agent, were extensively investigated. Polypropylene was found to degrade when prepared under atmospheric conditions; therefore, it was necessary to form droplets under nitrogen. Removal of the sizing from the fibre using pyrolysis and solvolysis techniques altered the surface morphology of the fibre and increased the interfacial shear strength (IFSS) by 4 and 33 %, respectively. A more significant improvement in the fibre-matrix adhesion was achieved by adding a maleic anhydride coupling agent at 2 wt%, which increased the IFSS by 320 %.

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“…The matrix was sheared off by Zwick Z005 (Ulm, Germany) type universal tester using a special droplet removing device [17,18] at room temperature. Electron micrographs were made on EOL JSM-6380LA (Tokyo, Japan) type electron microscope, with gold coated specimens.…”

Section: Methodsmentioning

confidence: 99%

“…value was determined according to as the ratio of deboning force and embedded surface of fiber [15,17]:…”

Section: Methodsmentioning

confidence: 99%

Investigation of fiber/matrix adhesion: test speed and specimen shape effects in the cylinder test

2013

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Abstract:The cylinder test, developed from the microdroplet test, was adapted to assess the interfacial adhesion strength between fiber and matrix. The sensitivity of cylinder test to pullout speed and specimen geometry was measured. It was established that the effect of test speed can be described as a superposition of two opposite, simultaneous effects which have been modeled mathematically by fitting two parameter Weibull curves on the measured datas.Effects of the cylinder size and its geometrical relation on the measured strength values have been analyzed by finite element method. It was concluded that the geometry has a direct influence on the stress formation. Based on the results achieved, recommendations were given on how to perform the novel single fiber cylinder test.

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A study of the effect of experimental test parameters on data scatter in microbond testing

Cited by 25 publications

References 21 publications

Finite element study of the microdroplet test for interfacial shear strength: Effects of geometric parameters for a carbon fibre/epoxy system

Finite element study of the microdroplet test for interfacial shear strength: Effects of geometric parameters for a carbon fibre/epoxy system

The usability of recycled carbon fibres in short fibre thermoplastics: interfacial properties

Investigation of fiber/matrix adhesion: test speed and specimen shape effects in the cylinder test

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