Prediction of Mode I and Mode II Interfacial Fracture Behaviors of Composite Laminates Considering Temperature Effects

Bimaterial systems in which two dissimilar materials are adhesively joined by a thin adhesive interlayer have been widely used in a variety of modern industries and engineering structures. It is well known that interfacial fracture is the most common failure mode for these bimaterial systems. Particularly, the interface fracture is a mixed mode in nature mode-I (pure peel) and mode-II (pure shear) due to the disrupted symmetry by the bimaterial configuration. Obviously, characterizing individual fracture modes, especially mode-I fracture, is essential in understanding and modeling the complex mixed mode fracture problems. Meanwhile, the J-integral is a highly preferred means to characterize the interfacial fracture behaviors of a bimaterial system because it cannot only capture more accurate toughness value, but also facilitate an experimental characterization of interfacial traction-separation laws (cohesive laws). Motivated by these important issues, a novel idea is proposed in the present work to realize and characterize the pure mode-I nonlinear interface fracture between bonded dissimilar materials. First, a nearly pure mode-I fracture test can be simply realized for a wide range of bimaterial systems by almost eliminating the mode-II component based on a special and simple configuration obtained in this work. Then, the concise forms of the J-integral are derived and used to characterize the interfacial fracture behaviors associated with classical and shear deformation beam theories. The proposed approach may be considered as a promising candidate for the future standard mode-I test method of bimaterial systems due to its obvious accuracy, simplicity, and applicability, as demonstrated by the numerical and experimental results.

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Seawater effects on interlaminar fracture toughness of glass fiber/epoxy laminates modified with multiwall carbon nanotubes

Journal of Composite Materials ◽

10.1177/0021998320950788 ◽

2020 ◽

pp. 002199832095078

Author(s):

Julio A Rodríguez-González ◽

Carlos Rubio-González

Keyword(s):

Carbon Nanotubes ◽

Fracture Toughness ◽

Glass Fiber ◽

Composite Laminates ◽

Multiwall Carbon Nanotubes ◽

Mode I ◽

Mode Ii ◽

Interlaminar Fracture Toughness ◽

Multiscale Composite ◽

Multiwall Carbon

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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An experimental study on interfacial fracture toughness of 3-D printed ABS/CF-PLA composite under mode I, II, and mixed-mode loading

Journal of Thermoplastic Composite Materials ◽

10.1177/0892705719874860 ◽

2019 ◽

pp. 089270571987486 ◽

Cited By ~ 2

Author(s):

Abdul Samad Khan ◽

Aaqib Ali ◽

Ghulam Hussain ◽

Muhammad Ilyas

Keyword(s):

Fracture Toughness ◽

Mixed Mode ◽

Interfacial Fracture ◽

Mode I ◽

Mode Ii ◽

Interfacial Fracture Toughness ◽

Fused Deposition ◽

Specimen Test ◽

Nozzle Temperature ◽

Printing Speed

Multimaterial structures made using fused deposition modeling (FDM) offer an attractive prospect for enhancing their mechanical properties and functionality. In this study, the interfacial fracture toughness of a unidirectional hybrid composite fabricated by FDM was studied through mechanical testing. The composite structure comprises acrylonitrile butadiene styrene and carbon fiber-reinforced polylactic acid. Since, de-adhesion or bond failure at the interface can occur under a combination of the different fracture modes, therefore, interfacial fracture toughness, in terms of the critical energy release rate, was characterized using double cantilever beam specimen test for mode I, end-notched flexural specimen test for mode II, and mixed-mode bending specimen test for mixed-mode I/II. Effects of varying process parameters, like printing speed and nozzle temperature, on the interfacial fracture toughness in mode I and II were also investigated. It was found that increasing the nozzle temperature and printing speed enhance the fracture toughness, both in mode I and II, but the effect of increasing nozzle temperature on mode II fracture toughness was quite significant.

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Experimental and numerical study on Mode I and Mode II interfacial fracture toughness of co-cured steel-CFRP hybrid composites

International Journal of Adhesion and Adhesives ◽

10.1016/j.ijadhadh.2021.103030 ◽

2021 ◽

pp. 103030

Author(s):

Youqiang Yao ◽

Pengcheng Shi ◽

Mingda Chen ◽

Gang Chen ◽

Cong Gao ◽

...

Keyword(s):

Fracture Toughness ◽

Hybrid Composites ◽

Numerical Study ◽

Interfacial Fracture ◽

Mode I ◽

Mode Ii ◽

Interfacial Fracture Toughness

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Characterization of cohesive model and bridging laws in mode I and II fracture in nano composite laminates

JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES ◽

10.15282/jmes.12.4.2018.24.0370 ◽

2018 ◽

Vol 12 (4) ◽

pp. 4329-4355 ◽

Cited By ~ 4

Author(s):

P. Ghabezi ◽

M. Farahani

Keyword(s):

Energy Release Rate ◽

Energy Release ◽

Release Rate ◽

Composite Laminates ◽

Beam Theory ◽

Critical Parameters ◽

Mode I ◽

Mode Ii ◽

Reliable Determination ◽

Cohesive Model

The cohesive model and traction-separation curves have brought a considerable possibility for researchers and fracture engineers to assess and simulate failure in composite laminates. Reliable determination of the traction–separation laws is very pivotal to the success of this approach in finite element methods. The objective of this paper is assessment of nanoparticles effect on bridging laws, cohesive mechanism and traction-separation parameters of nanocomposites mode I and II fracture. To do this analyzing of the experimental data from double cantilever beam, and end notched flexure tests including construction of the R-curves (energy release rate versus crack length), reconstruction of these curves in terms of the pre-crack tip opening and sliding displacement, and calculation of the corresponding bridging and traction-separation laws through the J-integral approach were carried out. For the calculation of the energy release rate in Mode I, three corresponding data reduction schemes namely Corrected Beam Theory, Experimental Compliance Method and Modified Compliance Calibration are utilized, while Compliance Calibration Method, Corrected Beam Theory and Compliance-Based Beam and II fracture are applied for that of mode II. The main concern of this research is introduction of critical parameters of two modified models to simulate mode I and II fracture. Adding 0.43 wt% nanoparticles to composite DCB samples leads to increase of 116%, 68% and 70% in GI,0 calculated by CBT, ECM and MCC respectively, and a 72% increase in GI,ss is measured by CBT, while this value for ECM and MCC is 110% and 48%. Adding 0.2 wt% nanoparticles to the composite samples results in 86% (50 MPa) increase in critical stress in mode II fracture calculated by method CBBM. This method presented the lowest value for critical displacement, fluctuated between 0.08-.11 mm in mode II.

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Mode I and Mode II Delamination of Flax/Epoxy Composite Laminate

MATEC Web of Conferences ◽

10.1051/matecconf/201820201002 ◽

2018 ◽

Vol 202 ◽

pp. 01002

Author(s):

Thamilarasu S. Rajendran ◽

Mahzan Johar ◽

Shukur Abu Hassan ◽

King Jye Wong

Keyword(s):

Fracture Toughness ◽

Composite Laminates ◽

Epoxy Composite ◽

Shear Fracture ◽

Natural Fibres ◽

Fracture Mechanisms ◽

Mode I ◽

Mode Ii ◽

Scanning Electron Micrographs ◽

Experimental Calibration

In recent decades, natural fibres are getting their attention as reinforcement in composite materials. This is because natural fibres are environmental friendly. However, delamination is commonly recognised as one of the earliest failures in composite laminates. The objective of the present work is to investigate mode I and mode II delamination behaviour of flax fabrics reinforced epoxy composite. The delamination characterisation was carried out using double cantilever beam (DCB) and three point end notched flexure (ENF) tests. The fracture toughness were calculated using experimental calibration method (ECM). Results showed that the average fracture toughness was 485 N/m and 962 N/m, respectively. Finally, through scanning electron micrographs, it was observed that the ply/ply debonding and fibre/matrix debonding were the major fracture mechanisms in DCB specimen. As for ENF specimen, shear fracture dominated the energy dissipation process.

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Review of Through-the-Thickness Reinforced z-Pinned Composites

Journal of Composites Science ◽

10.3390/jcs4010031 ◽

2020 ◽

Vol 4 (1) ◽

pp. 31 ◽

Cited By ~ 2

Author(s):

Vassilis Kostopoulos ◽

Nikolaos Sarantinos ◽

Stavros Tsantzalis

Keyword(s):

Mechanical Properties ◽

Composite Laminates ◽

Fatigue Loading ◽

Mode I ◽

Mode Ii ◽

Impact Properties ◽

Compression After Impact ◽

Out Of Plane ◽

Plane Direction ◽

The Impact

This work reviews the effects of z-Pins used in composite laminates as through-the-thickness reinforcement to increase the composite’s properties in the out-of-plane direction. The paper presents the manufacture and microstructure of this reinforcement type while also incorporating the impact of z-Pins on the mechanical properties of the composite. Mechanical properties include tensile, compression, flexure properties in static, dynamic and fatigue loads. Additionally, mode I and mode II properties in both static and fatigue loading are presented, as well as hygrothermal, impact and compression after impact properties.

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Influence of Milled Glass Fiber Fillers on Mode I & Mode II Interlaminar Fracture Toughness of Epoxy Resin for Fabrication of Glass/Epoxy Composites

Fibers ◽

10.3390/fib8060036 ◽

2020 ◽

Vol 8 (6) ◽

pp. 36

Author(s):

Kannivel Saravanakumar ◽

Vellayaraj Arumugam ◽

Rotte Souhith ◽

Carlo Santulli

Keyword(s):

Fracture Toughness ◽

Glass Fiber ◽

Composite Laminates ◽

Glass Fibers ◽

Mode I ◽

Mode Ii ◽

Additional Energy ◽

Maximal Increase ◽

Mode Ii Fracture Toughness ◽

Delamination Resistance

The present work is focused on improving mode I and mode II delamination resistance of glass/epoxy composite laminates (50 wt.% of glass fibers) with milled glass fibers, added in various amounts (2.5, 5, 7.5 and 10% of the epoxy weight). Including fillers in the interlayer enhances the delamination resistance by providing a bridging effect, therefore demanding additional energy to initiate the crack in the interlaminar domain, which results in turn in enhanced fracture toughness. The maximal increase of mode I and mode II fracture toughness and of flexural strength was obtained by the addition of 5% milled glass fiber. The mechanism observed suggests that crack propagation is stabilized even leading to its arrest/deflection, as a considerable amount of milled glass fiber filler was oriented transverse to the crack path. In contrast, at higher filler loading, tendency towards stress concentration grows due to local agglomeration and improper dispersion of excess fillers in inter/intralaminar resin channel, causing poor adhesion to the matrix, which leads to reduction in fracture toughness, strength and strain to failure. Fractured surfaces analyzed using scanning electron microscopy (SEM) revealed a number of mechanisms, such as crack deflection, individual debonding and filler/matrix interlocking, all contributing in various ways to improve fracture toughness.

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