Broughton, W R; Lodeiro, M J; Mulligan, D R (2000) Environmental degradation of undirectional composites. NPL Report. CMMT(A)250

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Abstract

Test methods have been developed within the Composites Performance and Design Project - Life Assessment and Prediction (CPD2) for determining the residual strength and remnant life of glass and carbon fibre-reinforced composites exposed to aggressive environments and/or static loads. This report considers convenient methods for obtaining basic strength-time data for unconditioned and chemically conditioned fibre bundles and continuous aligned fibre-reinforced rods. These test methods require shorter conditioning times and less manufacturing and testing costs in comparison with current practices.
The report considers: (i) tensile testing of moisture and chemical (i.e. sulphuric acid and sodium hydroxide solutions) pre-conditioned fibre bundles and fibre-reinforced rods; and (ii) creep rupture behaviour of moisture and chemical conditioned fibre bundles and fibre-reinforced rods. Moisture pre-conditioning involved immersion in deionised water at temperatures ranging from 23 o C to 70 o C for up to 42 days, whereas chemical conditioning involved exposure of fibre bundles to either sulphuric acid or sodium hydroxide solutions at room-temperature for periods no longer than 2 weeks.
The principal conclusions that can be drawn from the results are: (i) fibre tows and small diameter (i.e. 1.5 mm) composite rods are suitable for accelerated testing under combined static loads and hostile environments, with fibre tows offering a relatively rapid method for evaluating fibre sensitivity to chemical attack; (ii) carbon fibres are relatively impervious to moisture, whereas E-glass fibres are highly sensitive to chemical attack; and (iii) results from narrow laminate strips cannot be extrapolated to larger coupon specimens. The report includes recommendations on preparation and testing of fibre bundles and composite rods.

Item Type:	Report/Guide (NPL Report)
NPL Report No.:	CMMT(A)250
Subjects:	Advanced Materials Advanced Materials > Composites
Last Modified:	02 Feb 2018 13:17
URI:	http://eprintspublications.npl.co.uk/id/eprint/1585

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