Effect of Silane Concentrations on Mode I Interlaminar Fracture of Woven Silk/Epoxy Composites

2010 ◽  
Vol 150-151 ◽  
pp. 1171-1175 ◽  
Author(s):  
Zulkifli R. ◽  
Che Husna Azhari

The aim of the project is to study the effect of silane concentrations on the interlaminar fracture toughness, GIC of silk/epoxy composites. Woven silk fibre has been treated with five different silane concentrations and fabricated into a panel with two layers of silk fibre. The processing technique used to prepare the sample is by a vacuum bag in an autoclave. Six sets of panels were fabricated based on different 3-aminopropyl triethoxysilane silane concentrations which include one sets of specimens without treatment for comparison. Mode I test based on double cantilever beam specimens (DCB) method has been used over all the specimens. The results of the GIC were plotted and compared with the untreated composites panel. GIC of the composite has been found to increase when the silane concentrations exceeded certain minimum silane contents of 15 ml. During the test, crack propagation is stable and no fibre bridging occurred between both sides of fracture surfaces. All the failure that occurred were at the fibre-matrix interface. The GIC of woven silk/epoxy composites can be enhanced by surface treatment using coupling agent. Surface treatment has affected the properties of the composite panel by increasing the interlaminar fracture toughness by a maximum of 53% at a 5.8vol% silane concentrations.

2010 ◽  
Vol 97-101 ◽  
pp. 1697-1700
Author(s):  
Zulkifli R. ◽  
Che Husna Azhari

The aim of the project is to study the interlaminar fracture toughness, GIC of woven silk reinforced epoxy composite. Silk fibre has been treated with silane coupling agent and the silk/epoxy composites has been fabricated with different number of silk fibre layers. The processing technique used to prepare the sample is a vacuum bag cured in an autoclave. In this study, test specimens were fabricated by using silk fibre of between 8 to 14 layers. The first set of composites panel consisted of plain silk fibre while the second sets consisted of silk fibre which has been treated with 3-aminopropyl triethoxysilane. Mode I test based on double cantilever beam specimens (DCB) method have been used over all the specimens. The results of the GIC were plotted and compared. GIC of the composites in set 2 were found to be higher than the value in set 1. During the test, crack propagation is stable and no fibre bridging occurred between both sides of fracture surfaces. All the failure that occurred were at the fibre-matrix interface as seen using SEM. The GIC of woven silk/epoxy composites can be enhanced by surface treatment using coupling agent. Surface treatment and number of woven silk fibre layers has affected the interlaminar fracture properties of the composite panel.


Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2103
Author(s):  
Christophe Floreani ◽  
Colin Robert ◽  
Parvez Alam ◽  
Peter Davies ◽  
Conchúr M. Ó. Brádaigh

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.


2018 ◽  
Vol 1 (2) ◽  
Author(s):  
Mohamad Alsaadi 1,2 ◽  
Ahmet Erkliğ 2

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.


Author(s):  
Seyed Jalaledin Najafi ◽  
Hooshang Nosraty ◽  
Mahmood Mehrdad Shokrieh ◽  
Ali Akbar Gharehaghaji ◽  
Seyed Hajir Bahrami

2016 ◽  
Vol 36 (2) ◽  
pp. 121-136 ◽  
Author(s):  
F Bensadoun ◽  
I Verpoest ◽  
AW Van Vuure

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.


Sign in / Sign up

Export Citation Format

Share Document