Search results for "Carbon fibre composite"

Idrothermal ageing of ionizing radiation cured epoxy matrices for carbon fibre composites

2008

The control of the residual lifetimes of carbon fibre-reinforced composite pressure vessels

2015

International audience; The understanding of the degradation of carbon fibre composites, with emphasis on the use of these composites in filament-wound pressure vessels, is explored. Earlier studies by many researchers have led to a general appreciation of the mechanisms involved; however, only recently have both computational power and experimental techniques become sufficiently developed to allow for the use of quantitative analyses. It is shown that damage is controlled by fibre failure, and that initially this occurs randomly within the structure. In monotonic loading, the development of clusters of fibre breaks causes rapid failure; however, under maintained loads the kinetics of damag…

Quantifiable analysis of the failure of advanced carbon fibre composite structures leading to improved safety factors

2022

Abstract The increasing use of advanced composite materials means that they must now be considered as major materials for a wide variety of structures some of which will be in service for decades. There is therefore an important need to be able to quantify damage accumulation leading to failure in these materials particularly as they are often used in extreme situations for which failure must be avoided. This review shows how damage accumulation in many major composite structures is dominated by fibre failure but that the viscoelastic nature of the matrix induces time effects including delayed failure. It is shown that damage accumulation can be quantitatively modelled using a multi-scale a…

Fatigue behaviour of self-piercing riveting of aluminium blanks and carbon fibre composite panels

2012

In this article, the fatigue behaviour of self-piercing riveted joints in 2024-T6 aluminium sheets and carbon fibre composite panels is studied through experimental tests and numerical simulations. This study, aimed to evaluate the best process conditions and the mechanical behaviour of the joint itself, can be divided into few phases: the first one in which the static mechanical behaviour was investigated in order to evaluate the best process conditions (such as the best value of oil pressure of the riveting system) and the second one which had the purpose to determine the fatigue behaviour of the joint. Finally, a finite element method analysis of the riveting process was developed in or…

On the self-piercing riveting of aluminium blanks and carbon fibre composite panels

2010

In the present paper the possibility to join aluminium alloys blanks and carbon fibre composites panels by self-piercing riveting operation is considered. In particular a few case studies were carried out at the varying of the process parameters. The effectiveness of the obtained joints was tested through tensile tests and through fatigue ones; what is more the process mechanics was highlighted through proper macro and micro observations of the transverse sections of the joints. The failure mechanics of the obtained joints were also considered in order to highlight the mechanisms which occur and determine the lost of the load carrying capability of the joints. Finally a numerical model of t…

The influence of the rubber carboxyl functionality on the processability and properties of solid rubber modified epoxy mixtures

2005

A high molecular weight, carboxyl functionalised solid rubber was added to an epoxy resin-aromatic amino system developed for autoclave curing of honeycomb core composite structures. The achievement of an optimal balance of viscous flow and viscoelasticity of the resin, by controlling the nature and extent of cross-linking of the functionalised rubber, was proposed as a route to void-free honeycomb skins. The aim of the present investigation is to understand how the concentration of carboxylic groups of the rubber, prereacted with one of the epoxy monomers, affects the matrix resin flow properties. The concentration of carboxyl groups was changed by reacting them with a monofunctional epoxy…

A methodology for the control of the residual lifetimes of carbon fibre reinforced composite pressure vessels

2005

International audience; Pressure vessels must be periodically proof tested. Traditional techniques for metal vessels are inapplicable for composite vessels as the latter do not break by crack propagation so that the reasoning behind the traditional testing procedures is not appropriate. Damage accumulation leading to the degradation of a composite vessel is by fibre failure. Fibres show a wide distribution in strengths and loading a composite inevitably breaks some. The method which has been developed is supported by an analysis of delayed fibre failure due to the relaxation of the resin around fibre breaks. This provokes overloading of intact fibres neighbouring breaks. The time until a cr…