Delamination Fracture of Multidirectional Carbon-Fiber/Epoxy Composites under Mode I, Mode II and Mixed-Mode I/II Loading

1999 ◽  
Vol 33 (1) ◽  
pp. 73-100 ◽  
Author(s):  
N. S. Choi ◽  
A. J. Kinloch ◽  
J. G. Williams
Keyword(s):  
Carbon Fiber ◽  
Mixed Mode ◽  
Epoxy Composites ◽  
Mode I ◽  
Mode Ii ◽  
Delamination Fracture ◽  
Carbon Fiber Epoxy

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 A Study of the Interlaminar Fracture Toughness of Unidirectional Flax/Epoxy Composites

2020 ◽  
Vol 4 (2) ◽  
pp. 66 ◽  
Author(s):  
Yousef Saadati ◽  
Jean-Francois Chatelain ◽  
Gilbert Lebrun ◽  
Yves Beauchamp ◽  
Philippe Bocher ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Mixed Mode ◽  
Failure Modes ◽  
Glass Fibers ◽  
Epoxy Composites ◽  
Mode I ◽  
Mode Ii ◽  
Pure Mode ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture

Having environmental and economic advantages, flax fibers have been recognized as a potential replacement for glass fibers as reinforcement in epoxy composites for various applications. Its widening applications require employing failure criteria and analysis methods for engineering design, analysis, and optimization of this material. Among different failure modes, delamination is known as one of the earliest ones in laminated composites and needs to be studied in detail. However, the delamination characteristics of unidirectional (UD) flax/epoxy composites in pure Mode I has rarely been addressed, while Mode II and Mixed-mode I/II have never been addressed before. This work studies and evaluates the interlaminar fracture toughness and delamination behavior of UD flax/epoxy composite under Mode I, Mode II, and Mixed-mode I/II loading. The composites were tested following corresponding ASTM standards and fulfilled all the requirements. The interlaminar fracture toughness of the composite were determined and validated based on the specific characteristics of natural fibers. Considering the variation in the composite structure configuration and its effects, the results of interlaminar fracture toughness fit in the range of those reported for similar composites in the literature and provide a basis for the material properties of this composite.

Mixed-mode I/II interlaminar fracture toughness of carbon fiber/epoxy composites with the addition of multiwalled carbon nanotubes by spraying technique

2018 ◽  
Vol 52 (22) ◽  
pp. 3045-3052 ◽  
Author(s):  
JA Rodríguez-González ◽  
C Rubio-González
Keyword(s):  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Carbon Fiber ◽  
Multiwalled Carbon Nanotubes ◽  
Mixed Mode ◽  
Mode I ◽  
Interlaminar Fracture Toughness ◽  
Multiwalled Carbon ◽  
Bending Tests ◽  
Carbon Fiber Epoxy

This work reports the effect of multiwalled carbon nanotubes on mixed-mode I/II interlaminar fracture toughness ([Formula: see text]) of unidirectional carbon fiber/epoxy composite laminates made by prepregs. The carbon fiber/epoxy laminates were fabricated in an autoclave with a previous deposition of different multiwalled carbon nanotube contents at their middle plane interface by spraying technique. Mixed-mode bending tests were conducted on carbon fiber/epoxy laminate specimens under different mixed-mode ratios. The results of mixed-mode bending tests showed that the addition of multiwalled carbon nanotubes can effectively improve the [Formula: see text] of carbon fiber/epoxy laminates. With a 0.2 wt.% multiwalled carbon nanotubes content in carbon fiber/epoxy laminates, the [Formula: see text] under mixed-mode ratios of 0.2, 0.5 and 0.8 increased by 25%, 12% and 19%, respectively. These results were explained in terms of the damage mechanisms observed at the fracture surfaces of tested specimens by scanning electron microscopy.

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