Search results for "flax"

Effect of the UV exposure on the creep behaviour of PLA based green composites

2018

Green composites made of biodegradable matrices and lignocellulosic fibers are receiving growing attention from both academia and industries. Despite a wide literature can be found about mechanical behavior of such kind of composites, at the best of our knowledge, only limited information is available about their creep behavior [1] and no papers have been yet done on the effect of ultraviolet exposition. The tensile creep behavior at 40 °C of PLA based composites, containing flax and jute twill weave woven fabrics, produced through compression molding, was investigated. As preliminary characterization, quasi-static tensile tests were carried out on virgin and UV aged composites

Yield development of flax varieties and lines within variable environment in Latvia

2015

Flax is the multiple purpose crop cultivated in temperate region. Seeds of oil flax recently became important constituent for many industrial applications, such as pharmacy, medicine, food production <em>etc.</em> and have high prospective for use in Latvia. Understanding the underlying processes that limit seed yield in flax is major with respect to enhancing the breeding of flax for yield improvements. The aim of study was evaluated 29 flax varieties and lines (including 20 Latvian origins) plasticity of seed yield production in changeable environmental conditions. The experiment was carried out in the Agricultural Scientific Centre of Latgale on field trials over the period 2…

Contributions to the study of the Visco-elastoplastic behavior of a flax fiber – epoxy resin structural composite

2020

The study presented in the manuscript is positioned in a large context of development of new materials, with a reduced environmental impact. From the possibilities currently under scrutiny (especially in Europe), flax fiber reinforced composites are the most promising. Thanks to their low density and high mechanical properties, as well as their low energy costs, fuel the idea of their usage in structural composites, by replacing glass fibers. These biocomposites are already implemented in numerous applications. However, several scientifical and technical unknowns, especially their long-term behavior, are hindering their use in domains of high load conditions.The thesis proposes to study the…

Reglement für die Flachs-Wraake zu Riga

1861

The effect of mechanical defects on the strength distribution of elementary flax fibres

2009

Flax fibres are finding non-traditional applications as reinforcement of composite materials. The mechanical properties of fibres are affected by the natural variability in plant as well as the damage accumulated during processing, and thus have considerable variability that necessitates statistical treatment of fibre characteristics. The strength distribution of elementary flax fibres has been determined at several fibre lengths by standard tensile tests, and the amount of kink bands in the fibres evaluated by optical microscopy. Strength distribution function, based on the assumption that the presence of kink bands limits fibre strength, is derived and found to provide reasonable agreemen…

Modeling strength scatter of elementary flax fibers: The effect of mechanical damage and geometrical characteristics

2011

Elementary bast fibers, apart from acceptable specific mechanical properties, possess a marked variability in geometrical and damage characteristics, which affects their axial tensile strength. A strength distribution function is derived that allows for the effect of kink bands and the scatter of fiber diameter. The distribution function is validated by applying it to the experimental strength data of both intact, carefully hand-decorticated, and damaged elementary flax fibers obtained by standard processing. The results suggest that the presence of kink bands is a limiting factor for the fiber strength.

In situ monitoring of moisture uptake of flax fiber reinforced composites under humid/dry conditions

2021

The use of green materials such as natural fiber-reinforced composites represents an increasingly stringent prerogative in the future planning of industrial and non-industrial production. The optimization of these materials is the main aim of the current research, focused on the evaluation of the behavior of flax fiber reinforced composites exposed to isothermal adsorption and desorption cycles, at varying the partial pressure of water vapor (P/P0). For this purpose, the moisture uptake and the morphology changes of the composite material and their constituents were in situ monitored through a measurement protocol, by using a dynamic vapor sorption (DVS) analysis, coupled with an environmen…

Basic Modeling of the Visco Elastic Behavior of Flax Fiber Composites

2017

International audience; L’effet de massification automobile qui accompagne les besoins croissants de mobilité terrestre et l’offre de nouvelles infrastructures routières qui soutient de nouvelles demandes rendent les modèles de mobilité actuels de plus en plus difficilement acceptables. En effet, les personnes souffrent de l’inconfort des villes engorgées (nuisances), de l’insécurité lors de transports du fait de défaillances techniques ou humaines, de la très grande difficulté d’optimiser ses itinéraires en fonction des horaires ou circonstances exceptionnelles (accident par exemple). Par ailleurs, la mobilité se heurte toujours aux contraintes liées aux rigidités des infrastructures compo…

Contribution to the development of natural fibers' use in structural composites. Study of a Flax / Epoxy composite’s behavior when exposed to hygroth…

2018

In recent years there is renewed interest for bio-sourced composites, including those based on flax fibers, and especially in the field of transport, mobility and leisure. In fact, the lower energy cost and environmental impact of flax fiber give it an advantage over glass fiber, while competing with its specific mechanical properties. However, flax fibers based composites long-term behavior remains poorly known in damp environments and constitutes an obstacle to a wider use. This work aims to provide adapted parameters to produce a high-grade flax/epoxy composite and to contribute to improve the durability knowledge of these materials. First, the influence of many processing parameters [(i…

Multifunctional biosourced materials : durability of unidirectional recycled matrix composites reinforced with flax fibers

2022

Now more than ever, many engineering sectors are turning to natural fiber composites because of the need for more environmentally friendly solutions. One of the main challenges in developing the use of biocomposites in outdoor applications is the lack of knowledge about their long-term durability. The main objective of this work is to provide a better understanding of the mechanisms involved in photooxidative aging of unidirectional composites made of a virgin or recycled polypropylene matrix, reinforced with long flax fibers. In addition, this work aims to study the potential use of a recycled matrix by comparing the evolution of its behavior to photooxidative aging with a virgin matrix. T…