scholarly journals Studies on Mixed Mode Interlaminar Fracture Toughness of M55J/M18 Carbon/Epoxy Laminates

2000 ◽  
Vol 9 (5) ◽  
pp. 096369350000900 ◽  
Author(s):  
S. Jose ◽  
R. Ramesh Kumar ◽  
G. Venkateswara Rao ◽  
P. Sriram
Keyword(s):  
Fracture Toughness ◽  
Mixed Mode ◽  
Fracture Criterion ◽  
Experimental Studies ◽  
Mode I ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture ◽  
Delamination Fracture ◽  
Epoxy Material

Experimental studies are carried out to determine the interlaminar fracture toughness of unidirectional laminates made of M55J/M18 carbon/epoxy material under different mixed mode ratios ( G I/ G II). A mixed mode delamination fracture criterion using mixed mode bending specimens is developed. It is observed that when loading in mode I is predominant, G II has a considerable value but the opposite is not true when mode II is predominant.

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.

Influence of Temperature on Interlaminar Fracture Toughness of a Carbon Fiber-Epoxy Composite Material

2016 ◽  
Vol 1135 ◽  
pp. 35-51 ◽  
Author(s):  
Rita de Cássia Mendonça Sales ◽  
Bianca Lis Rossi Dias Endo ◽  
Maurício Vicente Donadon
Keyword(s):  
Fracture Toughness ◽  
Mixed Mode ◽  
Mechanical Resistance ◽  
Mode I ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Interlaminar Fracture ◽  
Delamination Resistance ◽  
Different Temperatures ◽  
Influence Of Temperature On

Composite materials have been increasingly used in the aerospace industry for the manufacturing of structures, because of the associated properties of low weight and high mechanical resistance. On the other hand, they have low delamination resistance. This paper presents the results of an experimental study performed to obtain the values of interlaminar fracture toughness (G) of a laminate under three different temperatures, using 0º carbon-epoxy prepreg fabric plies and manufactured via Hand lay up cured in autoclave (HLUP). Double Cantilever Beam (DCB) tests were performed to evaluate mode I toughness, Four Point Bend End Notched Flexure (4ENF) for mode II and Mixed Mode Bending (MMB) for mixed mode I / mode II at -54°C, 25°C and 80°C. The data were collected and analyzed using a routine developed in Matlab®. Finally, the relation between GI and GII through the failure envelope and the temperature influence on the interlaminar fracture toughness was assessed.

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.

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.

scholarly journals Improved Interlaminar Fracture Toughness and Electrical Conductivity of CFRPs with Non-Woven Carbon Tissue Interleaves Composed of Fibers with Different Lengths

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 803 ◽  
Author(s):  
Feng Xu ◽  
Bo Yang ◽  
Lijie Feng ◽  
Dedong Huang ◽  
Min Xia
Keyword(s):  
Electrical Conductivity ◽  
Fracture Toughness ◽  
Carbon Fibers ◽  
Mode I ◽  
Mode Ii ◽  
Thickness Direction ◽  
Interlaminar Fracture Toughness ◽  
Filtration Method ◽  
Interlaminar Fracture ◽  
Pull Out

Non-woven carbon tissue (NWCT) with different fiber lengths was prepared with a simple surfactant-assistant dispersion and filtration method and used as interleaving to enhance both delamination resistance and electrical conductivity of carbon fiber reinforced plastics (CFRPs) laminates. The toughing effect of NWCT on both Mode I and Mode II interlaminar fracture of CFRPs laminate is dependent on length of fibers, where the shorter carbon fibers (0.8 mm) perform better on Mode I interlaminar fracture toughness improvement whereas longer carbon fibers (4.3 mm) give more contribution to the Mode II interlaminar fracture toughness increase, comparing with the baseline composites, and the toughness increase was achieved without compromising of flexural mechanical properties. More interestingly, comparing with the baseline composites, the electrical conductivity of the interleaved composites exhibited a significant enhancement with in-plane and through-the-thickness direction, respectively. Microscopy analysis of the carbon tissue interleaving area in the laminate indicated that carbon fibers with shorter length can form into a 3D network with more fibers aligned along through-the-thickness direction compared with longer ones. The shorter fibers thus potentially provide more effective fiber bridges, pull-out and matrix deformation during the crack propagation and improve the electric conductivity significantly in through-the-thickness direction.

Interlaminar Fracture of CF/EP Composites Modified with Nano-Silica

2007 ◽  
Vol 121-123 ◽  
pp. 1403-1406 ◽  
Author(s):  
Shi Qiang Deng ◽  
P. Rosso ◽  
Lin Ye ◽  
Klaus Friedrich
Keyword(s):  
Fracture Toughness ◽  
Fracture Behaviour ◽  
Mode I ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Nano Silica ◽  
Interlaminar Fracture ◽  
Transverse Tension ◽  
Tension Tests ◽  
Nano Additives

Fracture toughness and other mechanical properties of epoxies modified with nano-slica particles were measured to elaborate effects of nano-additives on fracture behaviour of the modified epoxies. Interlaminar fracture behaviours of the nano-silica modified CF/EP composites were subsequently investigated by conducting Mode-I and Mode-II interlaminar fracture toughness tests as well as transverse tension tests. It was found that the fracture toughness of the nano-silica modified epoxies and the interlaminar fracture toughness of nano-silica modified CF/EP composites have been increased significantly (>50%), while the strength and modulus of the materials remain unchanged or slightly higher. In particular, the nano-silica modified epoxies showed only very little reduction in the glass transition temperature (Tg).

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