Search results for "A. Fibre"
showing 10 items of 78 documents
Environmentally Friendly Composites and Surface Treatments for Metal-to-Composite Hybrid Joints for Marine Application
2022
In this study, the use of natural fibres (flax and basalt) in combination with a recyclable epoxy matrix based on cleavable amines is suggested for improving the sustainability of marine industry. In addition, a new and eco-friendly anodizing process based on tartaric sulfuric acid solution (TSA) and a pore widening step in a NaOH aqueous solution was carried out on aluminium alloy (AA5083) to evaluate its effect on the adhesion strength and damage tolerance after low velocity impact of co-cured adhesive joints with a basalt fibre reinforced and recyclable laminate. The durability in marine environment was simulated by exposing samples to salt-fog spray conditions over a period of 90 days. …
Durability of flax-basalt hybrid composites for marine applications
2015
The aim of the present work is to evaluate the influence of external layers of mat basalt on the durability behaviour and performances of flax/epoxy laminates. To this scope, long-term aging tests were performed to evaluate the durability of the two different laminates in critical environmental conditions. In particular, Flax composites were constituted by ten layers of bidirectional flax fabric whereas hybrid laminates (i.e. Flax-Basalt) were produced by replacing four external layers of bidirectional flax with four layers of basalt mat. Both laminates had a total average thickness equal to 3 mm. The samples were exposed to critical environmental conditions following the ASTM B 117 standar…
Modelling the structure-property relationships of high performance PBAT-based biocomposites with natural fibers obtained from Chamaerops humilis dwar…
2022
Two fibrous fillers were achieved from stalks and leaves of Chamaerops humilis dwarf palm and tested as reinforcing agents for poly(butylene adipate co-terephthalate) (PBAT)-based composites. The influence of filler type and content on the morphomechanical properties of the green composites was assessed. The outcomes of tensile tests pointed out that both fillers are strong candidates to overcome the two main limiting aspects of PBAT, that is, the lack of both stiffness and cost-effectiveness, while preserving its stretchability and environmental sustainability. The remarkable stiffness increments (up to 300%), combined with fair retention of stretchability (33%) and doubled resistance, led…
Failure mechanisms of flax/epoxy laminates with open hole: a failure map
2017
Aim of this paper is the investigation of the pin/hole contact stress and failure mechanisms of flax/epoxy composite laminates underwent to tensile bearing tests. In particular, the maximum loads and failure modes are evaluated at varying joint geometry. In order to optimize the use of composite materials in structural applications, an experimental failure map, identifying main failure modes of mechanically fastened joints, is obtained by evaluating failure modes (i.e., net tension, shear out, cleavage and bearing) as a function of the pin diameter and the position of the hole from the free edge of the laminate. Main goal of this paper is give a simple experimental methodology to support th…
Observation of Optical Undular Bores in Multiple Four-Wave Mixing
2014
International audience; We demonstrate that wave-breaking dramatically affects the dynamics of nonlinear frequency conversion processes that operate in the regime of high efficiency (strong multiple four-wave mixing). In particular, by exploiting an all-optical-fiber platform, we show that input modulations propagating in standard telecom fibers in the regime of weak normal dispersion lead to the formation of undular bores (dispersive shock waves) that mimic the typical behavior of dispersive hydrodynamics exhibited, e.g., by gravity waves and tidal bores. Thanks to the nonpulsed nature of the beat signal employed in our experiment, we are able to clearly observe how the periodic nature of …
Water absorption and hydrothermal performance of PHBV/sisal biocomposites
2014
[EN] The performance of biocomposites of poly(hydroxybutyrate-co-valerate) (PHBV) and sisal fibre subjected to hydrothermal tests at different temperatures above the glass transition of PHBV (TH ¿ 26, 36 and 46 C) was evaluated in this study. The influences of both the fibre content and presence of coupling agent were focused. The water absorption capability and water diffusion rate were considered for a statistical factorial analysis. Afterwards, the physico-chemical properties of water-saturated biocomposites were assessed by Fourier-Transform Infrared Analysis, Size Exclusion Chromatography, Differential Scanning Calorimetry and Scanning Electron Microscopy. It was found that the water d…
A new eco-friendly chemical treatment of natural fibres: Effect of sodium bicarbonate on properties of sisal fibre and its epoxy composites
2016
Abstract Several researchers have shown how sisal fibres possess remarkable tensile properties that yield them good candidates as reinforcement in biocomposite materials. This work aims to evaluate the effect of an eco-friendly and cost effective surface treatment method based on the use of commercial sodium bicarbonate (i.e. baking soda) on properties of sisal fibre and its epoxy composites. In particular, raw sisal fibres were treated with a 10%w/w of sodium bicarbonate solution for different periods (24, 120 and 240 h), at room temperature. Changes occurring in sisal fibres were characterized through scanning electron microscope, Fourier transform infrared spectroscopy, thermogravimetric…
Mode I translaminar fracture toughness of high performance laminated biocomposites reinforced by sisal fibers: Accurate measurement approach and lay-…
2022
Abstract The present work performs a systematic experimental analysis of the translaminar fracture behavior of high performance biocomposites constituted by green epoxy reinforced by sisal fibers, by varying the main influence parameters as fiber concentration and lay-up. Despite the corrective function properly introduced to take into account the anisotropy as well as the use of the equivalent crack length, the study shows that the LEFM does not give accurate estimations of the fracture toughness, because the extension of the near tip damaged zone is higher than the singular dominated one. Accurate estimations can be obtained instead by the proposed modified area method that takes into acc…
Cylindrical metal-coated optical fibre devices for filters and sensors
1996
Novel fibre-optic components suitable for sensor applications and wavelength filters are reported. The devices consist of a tapered fibre whose uniform waist has been coated with a thin layer of gold. The operation principle is the resonant excitation of a surface plasma mode of the metal film.
Size control of InAs∕InP(001) quantum wires by tailoring P∕As exchange
2004
The size and emission wavelength of self-assembled InAs∕InP(001) quantum wires (QWrs) is affected by the P∕As exchange process. In this work, we demonstrate by in situ stress measurements that P∕As exchange at the InAs∕InP interface depends on the surface reconstruction of the InAs starting surface and its immediate evolution when the arsenic cell is closed. Accordingly, the amount of InP grown on InAs by P∕As exchange increases with substrate temperature in a steplike way. These results allow us to engineer the size of the QWr for emission at 1.3 and 1.55 μm at room temperature by selecting the range of substrate temperatures in which the InP cap layer is grown.