Determination of mode I and mode II static and fatigue delamination toughness of a laminated graphite/epoxy composite

2000 ◽  
Author(s):  
Anthony Vinciquerra
Keyword(s):  
Epoxy Composite ◽  
Mode I ◽  
Mode Ii ◽  
Delamination Toughness

scholarly journals Generation of R-Curve from 4ENF Specimens: An Experimental Study

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
V. Alfred Franklin ◽  
T. Christopher
Keyword(s):  
Composite Materials ◽  
Fracture Energy ◽  
Epoxy Composite ◽  
Beam Theory ◽  
Fiber Direction ◽  
Crack Growth Resistance Curve ◽  
Aerospace Applications ◽  
Delamination Toughness ◽  
Theory Solution

The experimental determination of the resistance to delamination is very important in aerospace applications as composite materials have superior properties only in the fiber direction. To measure the interlaminar fracture toughness of composite materials, different kinds of specimens and experimental methods are available. This article examines the fracture energy of four-point end-notched flexure (4ENF) composite specimens made of carbon/epoxy and glass/epoxy. Experiments were conducted on these laminates and the mode II fracture energy, GIIC, was evaluated using compliance method and was compared with beam theory solution. The crack growth resistance curve (R-curve) for these specimens was generated and the found glass/epoxy shows higher toughness values than carbon/epoxy composite. From this study, it was observed that R-curve effect in 4ENF specimens is quite mild, which means that the measured delamination toughness, GIIC, is more accurate.

Interlaminar fracture toughness of flax-epoxy composites

2016 ◽  
Vol 36 (2) ◽  
pp. 121-136 ◽  
Author(s):  
F Bensadoun ◽  
I Verpoest ◽  
AW Van Vuure
Keyword(s):  
Fracture Toughness ◽  
Epoxy Composite ◽  
Flax Fibre ◽  
Epoxy Composites ◽  
Mode I ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture ◽  
Brittle Polymer ◽  
Tensile Toughness

The purpose of this study was to determine the influence of fibre architectures on the interlaminar fracture toughness and tensile toughness of flax fibre epoxy composites. The fracture toughness was investigated for both Mode I (GIC) and Mode II (GIIC) for seven flax-epoxy architectures: one plain weave, two twill 2 × 2 weaves, a quasi-unidirectional and a unidirectional architecture, the UD’s being tested in both [0,90] and [90,0] composite lay-ups. The results of the Mode I and Mode II showed promising results of the flax-epoxy composite performance. The addition of flax fibre increases the GIC and GIIC of the composites over that of the unreinforced brittle polymer by at least two to three times. Further improvements are made with the use of woven textiles. The tensile toughness was found to be a good indicator of the capacity of a material to sustain perforation or non-perforation impact.

scholarly journals Determination of mode I and mode II fracture toughness of walnut and cherry in TR and RT crack propagation system by the Arcan test

Holzforschung ◽  
2017 ◽  
Vol 71 (12) ◽  
pp. 985-990 ◽  
Author(s):  
Koji Murata ◽  
Erik Valentine Bachtiar ◽  
Peter Niemz
Keyword(s):  
Fracture Toughness ◽  
Crack Propagation ◽  
Release Rate ◽  
Strain Energy ◽  
Shear Plane ◽  
Mode I ◽  
Mode Ii ◽  
Mode Ii Fracture ◽  
Mode Ii Fracture Toughness

AbstractTwo specimen types, each from walnut and cherry wood, were prepared for tangential-radial (TR) and radial-tangential (RT) crack propagation systems at 65% of RH and 20°C before mode I and mode II fracture toughness was determined through Arcan tests. It was found that fracture toughness in mode I is in agreement with literature data. In the mode II test, however, the crack propagated in the direction normal to the shear plane and not parallel to it. The release rate of strain energy in terms of the opening failure in mode II was lower than that in mode I. It can be concluded that it is difficult to determine the fracture toughness of RT or TR propagation in hardwood specimens in mode II.

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