Long term creep and stress rupture of aramid fibre

Abstract

The present paper describes a creep rupture investigation on aramid fibre yarns (Twaron 1000 and Kevlar 29) supplied by Teijin and Du Pont respectively. The ISO 9080 extrapolation procedure, which was developed for thermoplastic pipe materials, was used to model and interpret the results. The 4 parameter version of this procedure fitted the results well and gave useful predictions of the long term stress rupture behaviour, lending confidence to existing qualification procedures for the use of aramid fibre in reinforced thermoplastic pipe (RTP), and other applications involving continuous high tensile loads. Creep strain measurements on yarns showed a near constant degree of creep deformation per decade. Although they may involve some of the same mechanisms the creep and stress rupture processes appear to operate independently and on different time scales. It was found that creep deformation in aramid yarns is unlikely to be a significant problem at stress levels corresponding to a 20 year lifetime.

Keywords

ARAMID CREEP STRESS RUPTURE

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