2753 Mode I and Mode II Interlaminer Fracture Toughness of CFRP laminates Toughened by Carbon-nano-fiber

2007 ◽  
Vol 2007.1 (0) ◽  
pp. 667-668
Author(s):  
Masahiro ARAI ◽  
Kazutoshi MATSUSHITA ◽  
Koh-ichi SUGIMOTO ◽  
Morinobu ENDO
Keyword(s):  
Fracture Toughness ◽  
Mode I ◽  
Mode Ii ◽  
Cfrp Laminates ◽  
Nano Fiber

Mode II Interlaminar Fracture Toughness of CNF-CFRP Hybrid Composite

2006 ◽  
Author(s):  
Masahiro Arai ◽  
Koh-Ichi Sugimoto ◽  
Morinobu Endo
Keyword(s):  
Fracture Toughness ◽  
Carbon Fiber ◽  
Hybrid Composites ◽  
Beam Theory ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture ◽  
Cfrp Laminates ◽  
Nano Fiber ◽  
Hybrid Laminates

Interlaminar fracture toughness for mode II deformation were investigated for carbon fiber (CF)/epoxy laminates toughened by carbon-nano-fiber/epoxy interlayer. Vapor grown carbon fiber (VGCF) and vapor grown carbon ‘nano’ fiber (VGNF) were chosen as the stiffeners for the interlayer. In order to illustrate the effect of the interlayer on the model II fracture toughness of the laminates, several types of CFRP/CNF hybrid laminates were fabricated, which are composed of unidirectional prepregs and carbon nano fiber varying the thickness of the interlayer. Mode II interlaminar fracture toughnesses of the hybrid composites were evaluated by end notched flexure (ENF) test using short-type beam specimens. The fracture toughnesses were calculated by traditional beam theory using the energy release rate of the crack. From the experimental results, it is confirmed that the mode II interlaminar fracture toughnesses for hybrid laminates are from 2.0 to 3.0 times higher than that of original CFRP laminates, and the optimal thickness (area density) of the CNF interlayer exists. The difference in the effect of the interlayer fracture properties under mode II deformation was discussed on the bases of fractographic observations derived from scanning electric microscope.

scholarly journals Mixed-Mode Interlaminar Fracture Toughness of Glass and Carbon Fibre Powder Epoxy Composites—For Design of Wind and Tidal Turbine Blades

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2103
Author(s):  
Christophe Floreani ◽  
Colin Robert ◽  
Parvez Alam ◽  
Peter Davies ◽  
Conchúr M. Ó. Brádaigh
Keyword(s):  
Fracture Toughness ◽  
Carbon Fibre ◽  
Composite Structures ◽  
Mixed Mode ◽  
Epoxy Composites ◽  
Mode I ◽  
Mode Ii ◽  
Pure Mode ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture

Powder epoxy composites have several advantages for the processing of large composite structures, including low exotherm, viscosity and material cost, as well as the ability to carry out separate melting and curing operations. This work studies the mode I and mixed-mode toughness, as well as the in-plane mechanical properties of unidirectional stitched glass and carbon fibre reinforced powder epoxy composites. The interlaminar fracture toughness is studied in pure mode I by performing Double Cantilever Beam tests and at 25% mode II, 50% mode II and 75% mode II by performing Mixed Mode Bending testing according to the ASTM D5528-13 test standard. The tensile and compressive properties are comparable to that of standard epoxy composites but both the mode I and mixed-mode toughness are shown to be significantly higher than that of other epoxy composites, even when comparing to toughened epoxies. The mixed-mode critical strain energy release rate as a function of the delamination mode ratio is also provided. This paper highlights the potential for powder epoxy composites in the manufacturing of structures where there is a risk of delamination.

scholarly journals Effect of sewage sludge ash filler on mode I and mode II interlaminar fracture toughness of S-glass/epoxy composites

2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Mohamad Alsaadi 1,2 ◽  
Ahmet Erkliğ 2
Keyword(s):  
Fracture Toughness ◽  
Sewage Sludge ◽  
Epoxy Composites ◽  
Mode I ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Sewage Sludge Ash ◽  
Interlaminar Fracture ◽  
Glass Fiber Reinforced ◽  
Sludge Ash

In this study, the influence of sewage sludge ash (SSA) waste particle contents on the mechanical properties and interlaminar fracture toughness for mode I and mode II delamination of S-glass fiber reinforced epoxy composites were investigated. Composite laminate specimens for tensile, flexural double-cantilever beam (DCB) and end-notched flexure (ENF) tests were prepared and tested according to ASTM standards with 5, 10, 15 and 20 wt% SSA filled S-glass/epoxy composites. Properties improvement reasons was explained based on optical and scanning electron microscopy. The highest improvement in tensile and flexural strength was obtained with 10 wt% content of SSA. The highest mode I and mode II interlaminar fracture toughness’s were obtained with 15 wt% content of SSA. The mode I and mode II interlaminar fracture toughness’s improved by 33 and 63.6%, respectively, compared to the composite without SSA.

Combined Mode Fracture Toughness Measurement by the Disk Test

1978 ◽  
Vol 100 (2) ◽  
pp. 175-182 ◽  
Author(s):  
Hideo Awaji ◽  
Sennosuke Sato
Keyword(s):  
Fracture Toughness ◽  
Internal Crack ◽  
Mode I ◽  
Mode Ii ◽  
Mode Fracture ◽  
Fracture Toughness Measurement ◽  
Circular Specimen ◽  
Combined Mode ◽  
Toughness Measurement ◽  
Disk Test

The disk test in which a circular specimen with an internal crack is subjected to diametral compression is used to investigate combined mode I and mode II fracture. The stress intensity factors in the disk test are calculated numerically by means of the boundary collocation procedure and the dislocation method. Special care was taken to analyze the effect of the compression anvils. This method has the advantage, of allowing successive measurement of mode I, mode II and the combined mode fracture toughness under the same conditions. Some kinds of graphite, plaster and marble are examined to obtain the fracture toughness values, KIC, KIIC and the combined mode fracture criterion.

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