Is there a ply thickness effect on the mode I intralaminar fracture toughness of composite laminates?

In this work, the effect of seawater ageing on mode I and mode II interlaminar fracture toughness ([Formula: see text] and [Formula: see text]) of prepreg-based woven glass fiber/epoxy laminates with and without multiwall carbon nanotubes (MWCNTs) has been investigated. The first part of the investigation reports the moisture absorption behavior of multiscale composite laminates exposed to seawater ageing for ∼3912 h at 70 °C. Then, the results of mode I and mode II fracture tests are presented and a comparison of [Formula: see text] and [Formula: see text] for each type of material group and condition is made. Experimental results showed the significant effect of seawater ageing on [Formula: see text] of multiscale composite laminates due to matrix plasticization and fiber bridging. The improvement in [Formula: see text] of the wet glass fiber/epoxy laminate was about 50% higher than that of the neat laminate (without MWCNTs) under dry condition. It was also found that the presence of MWCNTs into composite laminates promotes a moderate increase (8%) in their [Formula: see text] as a result of the additional toughening mechanisms induced by CNTs during the delamination process. Scanning electron microscopy analysis conducted on fracture surface of specimens reveals the transition from brittle (smooth surface) to ductile (rough surface) in the morphology of composite laminates due to the influence of seawater ageing on the polymeric matrix and fiber/matrix interface.

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Experimental method for mode I fracture toughness of composite laminates using wedge loaded double cantilever beam specimens

Composites Part A Applied Science and Manufacturing ◽

10.1016/j.compositesa.2018.05.036 ◽

2018 ◽

Vol 112 ◽

pp. 119-125 ◽

Cited By ~ 9

Author(s):

Sota Oshima ◽

Akinori Yoshimura ◽

Yoshiyasu Hirano ◽

Toshio Ogasawara

Keyword(s):

Fracture Toughness ◽

Experimental Method ◽

Cantilever Beam ◽

Composite Laminates ◽

Double Cantilever Beam ◽

Mode I ◽

Mode I Fracture ◽

Mode I Fracture Toughness

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Effects of the Stacking Sequence, Material Nature and Addition of an Adhesive Film on the Delamination Resistance of Woven Composite Laminates in Mode I and II

Advanced Composites Letters ◽

10.1177/096369351502400101 ◽

2015 ◽

Vol 24 (1) ◽

pp. 096369351502400

Author(s):

P. Navarro ◽

J. Aubry ◽

F. Pascal ◽

S. Marguet ◽

J.F. Ferrero ◽

...

Keyword(s):

Fracture Toughness ◽

Composite Laminates ◽

Woven Fabrics ◽

Woven Composites ◽

High Fracture Toughness ◽

Mode I ◽

Woven Composite ◽

High Fracture ◽

Adhesive Film ◽

Woven Composite Laminates

Woven composites are well-known for their good transverse properties and for their high fracture toughness. The damage mechanisms leading to delamination in woven composites are identified in mode I and II and are compared with those occurring in unidirectional laminates. The influence of several parameters, including the draping sequence and the fibre / matrix interface on the fracture toughness of woven composite laminates is studied. Pure Mode I and Mode II tests are carried out on several carbon/epoxy and glass/epoxy woven composites configurations and the differences observed are discussed from a fractographic point of view. The study illustrates the high fracture toughness of the composites made of woven fabrics as well the influence of the orientation of the plies, the nature of the fibres and the addition of an adhesive film.

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The effects of through-the-thickness stitching on the Mode I interlaminar fracture toughness of flax/epoxy composite laminates

Materials & Design ◽

10.1016/j.matdes.2016.07.093 ◽

2016 ◽

Vol 109 ◽

pp. 659-669 ◽

Cited By ~ 50

Author(s):

M. Ravandi ◽

W.S. Teo ◽

L.Q.N. Tran ◽

M.S. Yong ◽

T.E. Tay

Keyword(s):

Fracture Toughness ◽

Composite Laminates ◽

Epoxy Composite ◽

Mode I ◽

Interlaminar Fracture Toughness ◽

Interlaminar Fracture

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The Thickness Effect of PSF Nanofibrous Mat on Fracture Toughness of Carbon/Epoxy Laminates

Materials ◽

10.3390/ma14133469 ◽

2021 ◽

Vol 14 (13) ◽

pp. 3469

Author(s):

Hamed Saghafi ◽

Ali Nikbakht ◽

Reza Mohammadi ◽

Dimitrios Zarouchas

Keyword(s):

Fracture Toughness ◽

Composite Laminates ◽

Double Cantilever Beam ◽

Thickness Effect ◽

Toughening Mechanism ◽

Geometrical Features ◽

Electrospinning Method ◽

Fracture Tests ◽

Mat Thickness ◽

First Time

The geometrical features of nanofibers, such as nanomat thickness and the diameter of nanofibers, have a significant influence on the toughening behavior of composite laminates. In this study, carbon/epoxy laminates were interleaved with polysulfone (PSF) nanofibrous mats and the effect of the PSF nanomat thickness on the fracture toughness was considered for the first time. For this goal, the nanofibers were first produced by the electrospinning method. Then, double cantilever beam (DCB) specimens were manufactured, and mode-I fracture tests were conducted. The results showed that enhancing the mat thickness could increase the fracture toughness considerably (to about 87% with the maximum thickness). The toughening mechanism was also considered by presenting a schematic picture. Micrographs were taken using a scanning electron microscope (SEM).

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Impact. Estimation Method for Mixed Mode (I+II) Interlaminar Fracture Toughness of Composite Laminates under Low-Velocity Impact Loading.

Journal of the Society of Materials Science Japan ◽

10.2472/jsms.50.235 ◽

2001 ◽

Vol 50 (3) ◽

pp. 235-241 ◽

Cited By ~ 1

Author(s):

Takayuki KUSAKA ◽

Noriyo HORIKAWA ◽

Masayoshi MASUDA ◽

Shinichi ADACHI

Keyword(s):

Fracture Toughness ◽

Impact Loading ◽

Composite Laminates ◽

Mixed Mode ◽

Estimation Method ◽

Low Velocity Impact ◽

Mode I ◽

Interlaminar Fracture Toughness ◽

Low Velocity ◽

Velocity Impact

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Improvement of Vibration Damping Capacity and Fracture Toughness in Composite Laminates by the Use of Polymeric Interleaves

10.1115/imece1999-0213 ◽

1999 ◽

Author(s):

Ronald F. Gibson ◽

Hui Zhao

Keyword(s):

Fracture Toughness ◽

Composite Laminates ◽

Critical Thickness ◽

Vibration Damping ◽

Thickness Effect ◽

Damping Capacity ◽

Mode Ii ◽

Interlaminar Fracture Toughness ◽

Interlaminar Fracture ◽

Mode Ii Fracture Toughness

Abstract It is shown that simultaneous improvement of vibration damping capacity and interlaminar fracture toughness in composite laminates can be achieved by using polymeric interleaves between the composite laminae. The specific case of Mode II interlaminar fracture toughness and flexural damping capacity of interleaved composite laminates is studied. Graphite/epoxy, E-glass/epoxy and E-glass/polyetherimide composite laminates with polymeric interleaves of several different thicknesses and materials were tested using both the end notch flexure (ENF) test for Mode II fracture toughness and the impulse-frequency response test for flexural damping capacity. The Mode II energy release rate GIIc for all three composites increased linearly with increasing interleaf thickness up to a critical thickness, then dropped off with further increases in thickness. The damping loss factor η for all three composites increased linearly with increasing interleaf thickness up to the maximum thickness. Analytical models for predicting the influence of interleaves on GIIc and η are developed, along with a hypothesis for the critical thickness effect with regard to fracture toughness.

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