Improvement in Fiber Testing of High‐Modulus Single‐Filament Materials

An instrumented indentation method is established to accurately measure the local elastic-plastic material properties of a single fiber by accounting for the additional sources of compliance associated with fiber indentation. The Oliver-Pharr instrumented indentation data analysis method is compared for indentation of a standard, planar fused silica sample and in the radial direction of homogeneous, isotropic E-glass fibers of two different diameters. Compliance contributions from substrate deflection and other nonindentation-related fiber deflections are quantified and shown to be negligible. The added compliance observed is attributed to the lack of constraint due to the finite geometry of a curved fiber surface. This compliance contribution is accounted for by using a proposed area correction to capture the geometry of the curved fiber-probe contact combined with a structural compliance correction. Implementation of these corrections to experimental indentation curves results in accurate measurements of the fiber elastic modulus and hardness.

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“…(6)- (9), h 0 c is the contact height in the transverse plane for contact depth h c in a flat plane. In Fig.…”

Section: B Measuring Single Filament Indentation Propertiesmentioning

confidence: 99%

“…entire filament) properties of fibers through various microtensile testing and compression techniques. [1][2][3][4][5][6][7][8][9][10][11] In this study, the focus will be on material deformation under indentation and measuring the local properties of isotropic, homogeneous E-glass fibers in the radial direction.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear indentation of fibers

2011

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“…The most common technique, the compliance method, corrects the total displacement measured on a universal testing machine by excluding strain due to components other than the fiber itself (ASTM 0-3379-75; Li and Langley, 1985). Reliable measurement of modulus requires high accuracy in measurement of strain.…”

Section: Youngs Modulusmentioning

confidence: 99%

Carbide, Nitride and Boride Materials Synthesis and Processing

Weimer¹

1997

254

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“…Obviously, the two effects will result in low stress, high strain, and low modulus for the fiber being measured. 5 Third, there are various types of damage to the fiber in the sample preparation and testing process, such as picking a fiber up from a bundle, adhering the fiber to a window card, mounting the fiber sample to the tensile machine, and even the chemical action of adhesives on the fiber.…”

Section: Introductionmentioning

confidence: 99%

“…Chi et al 4 concluded that there are shortcomings in single-filament measurements, such as the difficulty of extracting individual fibers from a bundle and the loss of weaker fibers because they are brittle and easy to fracture in the sampling. Li and Langley 5 proposed a system compliance factor derived from the plotting of the indicated compliance versus the gauge length over the square of the fiber diameter, instead of versus the gauge length alone. Huang et al 6 also studied an improved method to obtain a more accurate modulus in single-filament measurements.…”

Section: Introductionmentioning

confidence: 99%

Tensile strength and its variation for PAN‐based carbon fibers. II. Calibration of the variation from testing

Jiangwei

2007

J of Applied Polymer Sci

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ABSTRACT:The tensile behavior of carbon fibers shows large scattering. This is due to the fiber itself and the testing operations. Because of the high tenacity and modulus, low strain, and easy breakability in bending, not only is the tensile test for single carbon fibers extremely difficult, but the measured results are also oppugned. To achieve a reliable and accurate characterization, several factors influencing the objective and exact testing of single carbon fibers have been measured and discussed, including the wrong pretension, nonaxial stretching, and adhesion effects. The experimental results indicate that the error of strain causing them ranges from 1.5 to 12.3%. Because of the typical linear stress-strain curves of carbon fibers, the ratio of the strain error to the modulus error is approximately equal to 1 : 1, so the calibration of the measured strain must be conducted for the accurate evaluation of the modulus and itself. The calibration is put forward.

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Improvement in Fiber Testing of High‐Modulus Single‐Filament Materials

Cited by 27 publications

References 1 publication

Nonlinear indentation of fibers

Nonlinear indentation of fibers

Carbide, Nitride and Boride Materials Synthesis and Processing

Tensile strength and its variation for PAN‐based carbon fibers. II. Calibration of the variation from testing

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