Showing papers by "Emmanuel Chailleux published in 2003"

Modelling the Non-Linear Viscoelastic and Viscoplastic Behaviour of Aramid Fibre Yarns

Abstract: A non-linear viscoelastic viscoplastic model is proposed for the tensilebehaviour of aramid fibres, based on an analysis of the deformationmechanisms of these materials. This model uses the macroscopicformulation developed by Schapery together with the plasticity conceptof Perzyna. A simple identification procedure for the model parametershas been developed using creep/recovery cycles at different load levels.The identification reveals that two of the four parameters of theviscoelastic model (g 1 and a σ) are independent of stresslevel. This may be due to the simple and regular nature of the fibrestructure. The model enables the parameters which characterise thenon-linear reversible viscoelasticity to be identified independentlyfrom those which characterise the viscoplasticity. The model predictionsare compared to experimental data for a more complex load sequence andreasonable correlation is obtained.

Prediction of the long term behavior of synthetic mooring lines

Abstract: The stiffness and short term behavior of polyester mooring lines are now reasonably well understood and these materials are finding many applications offshore. Much less is known about the long term behavior of this and other synthetic materials (aramids, HMPE). This paper presents results from creep and cyclic loading tests on these three materials at different scales, from single fiber up to ropes. The behavior of aramid and polyester is compared with the predictions of a viscoelastic-viscoplastic model which includes bedding-in effects. For HMPE lines it is creep which dominates line design, and data are compared to an existing creep model. New material developments which significantly improve creep performance of HMPE-based ropes are presented.