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| Derombise, Guillaume; Van Schoors, L. Vouyovitch; Klop, E. A.; Schotman, A. H. M.; Platret, G.; Davies, Peter. |
| Aramid fibres are high-performance materials proposed in geotextiles for alkaline ground reinforcement. To study their durability in such environments, accelerated ageing has been carried out at pH 9 and at pH 11 for up to one and a half years. First, the lateral and longitudinal crystallite sizes have been determined before and after ageing under these conditions by Wide-Angle X-ray diffraction. Next, the tensile fracture surfaces have been observed after different ageing times by scanning electron microscopy. Finally, molecular weight changes have been evaluated by size exclusion chromatography. This study highlights the dependence of structural changes on the ageing conditions. A structural degradation scheme is proposed. |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00065/17614/15305.pdf |
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| Derombise, Guillaume; Chailleux, Emmanuel; Forest, Bertrand; Riou, Luc; Lacotte, Nicolas; Van Schoors, L. Vouyovitch; Davies, Peter. |
| Aramid fibers are today proposed in ropes and cables for marine applications. As these highly crystalline materials are loaded in tension for a longer period in seawater, their long-term mechanical behavior has to be understood. However, the response is time-dependent and exhibits a nonlinear effect with stress. In this study, two types of aramid fibers are studied: Twaron and Technora. Mechanical properties are measured using static tensile tests and creep-recovery tests. A nonlinear viscoelastic-viscoplastic model, based on the Schapery formulation, allows discriminating between the instantaneous and the time-dependent response as well as the reversible and nonreversible phenomena (plasticity). First, this procedure allows the overall mechanical behavior... |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00039/15049/12604.pdf |
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