scholarly journals Toughening Behavior of Carbon/Epoxy Laminates Interleaved by PSF/PVDF Composite Nanofibers

2020 ◽  
Vol 10 (16) ◽  
pp. 5618 ◽  
Author(s):  
Hamed Saghafi ◽  
Roberto Palazzetti ◽  
Hossein Heidary ◽  
Tommaso Maria Brugo ◽  
Andrea Zucchelli ◽  
...  
Keyword(s):  
Composite Laminates ◽  
Polyvinylidene Fluoride ◽  
Composite Nanofibers ◽  
Electrospun Nanofibers ◽  
Critical Energy ◽  
Mode I ◽  
Mode Ii ◽  
Critical Energy Release Rate ◽  
Mode Ii Loading ◽  
Combination Mode

This paper presents an investigation on fracture behavior of carbon/epoxy composite laminates interleaved with electrospun nanofibers. Three different mats were manufactured and interleaved, using only polyvinylidene fluoride (PVDF), only polysulfone (PSF), and their combination. Mode-I and Mode-II fracture mechanics tests were conducted on virgin and nanomodified samples, and the results showed that PVDF and PSF nanofibers enhance the Mode-I critical energy release rate (GIC) by 66% and 51%, respectively, while using a combination of the two registered a 78% increment. The same phenomenon occurred under Mode-II loading. SEM micrographs were taken, to investigate the toughening mechanisms provided by the nanofibers.

Mode I Interlaminar Fracture Characterization of CFRP Composite Laminates

2012 ◽  
Vol 488-489 ◽  
pp. 552-556 ◽  
Author(s):  
S.S.R. Koloor ◽  
H. Hussin ◽  
M.N. Tamin
Keyword(s):  
Composite Laminates ◽  
Critical Energy ◽  
Fracture Plane ◽  
Mode I ◽  
Critical Energy Release Rate ◽  
Fracture Characterization ◽  
Delamination Crack ◽  
Deformation Response ◽  
Dcb Specimen ◽  
Cfrp Composite

This study examines the deformation response of CFRP composites with preexisting delamination crack under Mode I loading. A DCB specimen is used in a series of Mode I interlaminar tests, each having a different initial delamination crack length. The 48-ply composite laminate has a symmetric ply sequence with 0/0 fiber orientation at the mid-plane. Apparent toughness is indicated by the composite specimen with a starter film insert, likely due to the presence of a neat pocket of resin at the front of the starter crack. The compliance of pre-delamination cracked specimens increases faster beyond the normalized delamination length, a/L of 0.68 due to effects of severe deflection of the longer DCB specimen arm. The critical energy release rate, GIC = 0.5 N/mm is determined based on pre-cracked DCB specimens. Fractographic analysis revealed a smooth fracture plane that indicates interface delamination as the primary failure mode.

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

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.

Effect of fixation stitches on out-of-plane response of textile non-crimp fabric composites

2018 ◽  
Vol 48 (7) ◽  
pp. 1151-1166 ◽  
Author(s):  
Somen K Bhudolia ◽  
Kenneth KC Kam ◽  
Pavel Perrotey ◽  
Sunil C Joshi
Keyword(s):  
Fracture Toughness ◽  
Composite Laminates ◽  
Peak Load ◽  
Experimental Studies ◽  
Critical Energy ◽  
Critical Energy Release Rate ◽  
Mode I Fracture Toughness ◽  
Out Of Plane ◽  
Static Indentation ◽  
Sem Investigation

Non-crimp fabrics are fabric tapes stitched to an adjacent orthogonal fabric with no associated crimp. In the current research, the effect of fixation polyester stitches in improving through-the-thickness properties of non-crimp fabric composite laminates is investigated. Detailed experimental studies on interlaminar fracture toughness and static indentation properties of stitched and unstitched thin ply carbon fibre epoxy composites have been conducted. About 23% higher peak load and 37% higher energy absorption were noticed during static indentation tests for the stitched ply composites. A detailed SEM investigation has shown that the stitch-stitch interaction ‘within a bi-angle ply’ and ‘between the bi-angle ply’ plays a significant role in reducing the delamination extent. The critical energy release rate during Mode I fracture toughness of stitched composites was found to be 26.5% higher and SEM investigation depicted that the stitches promote the intra-laminar delamination and enhance the toughness of the composite.

The Effect of Temperature, Thickness, and Working Time on Adhesive Properties

2018 ◽  
Author(s):  
Nicholas Aerne ◽  
John P. Parmigiani
Keyword(s):  
Cantilever Beam ◽  
Design Process ◽  
Working Time ◽  
Effect Of Temperature ◽  
Control Group ◽  
Mode I ◽  
Mode Ii ◽  
Adhesive Properties ◽  
Loading Modes ◽  
Mode Ii Loading

The need for lightweight components and non-destructive fastening techniques has led to the growth of adhesive use in many industries. Modeling the behavior of adhesives in fastening joints can help in the design process to make an optimized joint. To optimize joints in the design process, the loading conditions, environmental conditions of service, thickness of bond, and bonding procedures all need to be refined for the adhesive of interest. However, in available technical data sheets of adhesives provided by manufactures there is a gap in what is sufficient to accurately model and predict the behavior of real-world adhesive conditions. This body of research presents the results of the effects of temperature, thickness, and working time on adhesive properties. These effects can be observed with test specimens from the loading modes of interest. The loading modes of interest are mode I and mode II loading for the current study. The specimen for mode I loading is the Double Cantilever Beam, and for mode II loading is the Shear Loaded Dual Cantilever Beam. The effect of temperature will be tested by testing each specimen at −20°C, 20°C, and 40°C. Two bond thicknesses for adhesive thickness effects were tested. The working time had a control group bonded in the recommended working time and an expired working time group where the specimens were not joined until 10 minutes had passed from the recommended working time. Triplicates of each specimen at the respective conditions were tested. The adhesive selected for this research was Plexus MA832. The results of the experiment show that adhesive factors such as temperature, thickness, and working time can have degrading effects on adhesive performance in mode I and mode II.

Sign in / Sign up

Export Citation Format

Share Document