scholarly journals Evaluation of Mode II Static Interlaminar Fracture Toughness in 0º/45º-Oriented Layers of CFRP Laminates

2018 ◽  
Vol 44 (5) ◽  
pp. 195-202 ◽  
Author(s):  
Yoshiki FURUSAWA ◽  
Hiroki SUGIMOTO ◽  
Hiroshi SAITO ◽  
Mototsugu TANAKA ◽  
Manato KANESAKI ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture ◽  
Cfrp Laminates ◽  
Oriented Layers

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.

EFFECTS OF TEMPERATURE ENVIRONMENT ON MODE II INTERLAMINAR FRACTURE TOUGHNESS IN ASYMMETRIC CFRP LAMINATES

2021 ◽  
Author(s):  
RYOSUKE IWAMA ◽  
HIROSHI SAITO ◽  
ISAO KIMPARA
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanism ◽  
Coupling Effect ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture ◽  
Cfrp Laminates ◽  
Out Of Plane ◽  
Practical Temperature ◽  
Coupling Components

When delamination occurs in CFRP laminates due to impact, a portion of the laminate structure becomes asymmetric across the delamination in the thickness direction, resulting in a coupling effect of in-plane and out-of-plane deformations. Thus, it is important to evaluate the coupling effects on the interlaminar fracture toughness and fracture mechanism in CFRP laminates. In addition, it is necessary to withstand practical temperature environments. Based on Verchery's approach, the authors intentionally prepared asymmetric laminates with non-zero and zero-coupling components in the classical lamination theory to evaluate the effects of coupling components on the interlaminar fracture toughness in CFRP laminates. In this study, the Mode II interlaminar fracture toughness of CFRP laminates with and without coupling components in the stiffness matrix was measured by the end notched flexure (ENF) test in the temperature range from room temperature to 80°C. The relationship between the temperature and the interlaminar fracture toughness was quantitatively evaluated. Fracture surface observation was also conducted to clarify the fracture mechanism.

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.

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