Damage Self-Diagnosis in Carbon Fiber-Reinforced Composites Under Fatigue Loading

An experimental study was conducted to sense interlaminar delamination in carbon-fiber composites utilizing inherent material piezoresistivity. Damage detection was carried out using discrete electrodes mounted on a Double Cantilever Beam (DCB) specimen. The DCB composite specimens were tested for fatigue interlaminar fracture. The traditional two-point probe and four-point probe technique were employed to measure the through-thickness electrical resistance change. Optical marker method was also used to detect interlaminar crack growth. The results show that the two-point probe measurements did not capture effectively the delamination propagation while the four-point probe measurement showed a promising sensing capability in terms of delamination propagation.

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Bisphenyl-Polymer/Carbon-Fiber-Reinforced Composite Compared to Titanium Alloy Bone Implant

International Journal of Polymer Science ◽

10.1155/2011/168924 ◽

2011 ◽

Vol 2011 ◽

pp. 1-11 ◽

Cited By ~ 6

Author(s):

Richard C. Petersen

Keyword(s):

Titanium Alloy ◽

Carbon Fiber ◽

Polymer Processing ◽

Fiber Reinforced Composites ◽

Carbon Fiber Composites ◽

Reinforced Composites ◽

Fiber Reinforced ◽

Implant Surface ◽

Carbon Fiber Reinforced Composites ◽

Carbon Fiber Reinforced

Aerospace/aeronautical thermoset bisphenyl-polymer/carbon-fiber-reinforced composites are considered as new advanced materials to replace metal bone implants. In addition to well-recognized nonpolar chemistry with related bisphenol-polymer estrogenic factors, carbon-fiber-reinforced composites can offer densities and electrical conductivity/resistivity properties close to bone with strengths much higher than metals on a per-weight basis.In vivobone-marrow tests with Sprague-Dawley rats revealed far-reaching significant osseoconductivity increases from bisphenyl-polymer/carbon-fiber composites when compared to state-of-the-art titanium-6-4 alloy controls. Midtibial percent bone area measured from the implant surface increased when comparing the titanium alloy to the polymer composite from 10.5% to 41.6% at 0.8 mm,P<10−4, and 19.3% to 77.7% at 0.1 mm,P<10−8. Carbon-fiber fragments planned to occur in the test designs, instead of producing an inflammation, stimulated bone formation and increased bone integration to the implant. In addition, low-thermal polymer processing allows incorporation of minerals and pharmaceuticals for future major tissue-engineering potential.

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Carbon Nanotube Layer for Reduction of Fiber Print-Through in Carbon Fiber Composites

Advances in Polymer Technology ◽

10.1155/2019/6520972 ◽

2019 ◽

Vol 2019 ◽

pp. 1-11 ◽

Cited By ~ 1

Author(s):

Joana F. Guedes ◽

Marta S. S. Martins ◽

Ramiro Martins ◽

Nuno Rocha

Keyword(s):

Carbon Nanotube ◽

Carbon Fiber ◽

Production Method ◽

Fiber Composites ◽

Fiber Reinforced Composites ◽

Carbon Fiber Composites ◽

Reinforced Composites ◽

Space Applications ◽

Scanning Electron Microscopy Morphology ◽

Carbon Fiber Reinforced Composites

Fiber print-through effect is a limitation to the use of carbon fiber-reinforced composites in space applications, namely, mirror telescopes. Replica method is used for the production of lightweight telescope mirrors. However, this method requires a polished mandrel, increasing considerably the final cost. In this work, we report a cheaper and simpler alternative production method, which consists in the addition of a carbon nanotube filled epoxy resin layer on the surface of carbon reinforced composites, in order to reduce fiber print-through of the materials. The influence of different carbon nanotube functionalizations, concentrations, and dispersion levels are also assessed. The surface properties are evaluated by interferometry (roughness and waviness) and scanning electron microscopy (morphology). The results show that the waviness, roughness, and consequently fiber print-though are considerably reduced with the addition of a thin layer of nonfunctionalized carbon nanotubes.

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