A. G. Gibson

The post-fire integrity of pultruded phenolic/glass and polyester/glass floor gratings, of the type used offshore and elsewhere, was investigated. The aim was to determine whether glass/phenolic gratings may be safely walked on, post-fire, by offshore workers and fire-fighting teams. The load to be resisted was identified as equivalent to a running person carrying a load, the combined mass being 150 kg. The maximum resulting dynamic strains were determined by strain gauges on the undersides of the individual beam elements of gratings. This enabled target values of post-fire bending resistance to be identified. Individual beam elements from the gratings were exposed to heat fluxes of 12.5, 37.5 and 100 kW/m ² using a propane burner, for periods up to 16 min, after which the residual strength was measured. Phenolic gratings showed longer ignition times, with lower flame and smoke emission, as well as greater post-fire strength compared to polyester ones. At the lowest flux, 12.5 kW/m ² , all gratings remained serviceable beyond 16 min. At higher heat fluxes, the phenolic gratings retained some post-fire strength, assisted by the formation of a carbonaceous char binding the fibres. However, this was somewhat below the target level. A study of the effect of testing speed indicated that fire-exposed gratings are not especially strain-rate sensitive.

This article presents relationships for the through-thickness elastic constants of composite laminates, needed for modelling three-dimensional stress problems. Using the individual ply elastic constants together with the in-plane laminate elastic constants (from laminate theory) results in explicit relationships for, ν₁₃, ν₂₃, E₃, G₁₃ and G₂₃. The Poisson’s ratio and Young’s modulus expressions apply to all laminate types. The shear modulus relationships apply to balanced laminates, but are extendable to other laminate types. Relationships are developed here for angle-ply, cross-ply and quasi-isotropic laminates. Results are presented for glass/epoxy and carbon/epoxy laminates, above and below the resin T_g. The importance of coupling stresses and their influence on ν₁₃, ν₂₃ and E₃ is underlined. It is shown, for instance, that equating the laminate through-thickness modulus to the individual ply value can result in a significant under-estimate.

This paper discusses the characterization and modeling of thermoplastic and thermosetting matrix composites under load in fire. Small-scale tests were found to provide a cost-effective means of characterizing load-bearing behavior of composites in fire and a useful framework for materials development. This paper demonstrates the modeling of thermal and decomposition behavior during the test and the extension of this modeling to include mechanical response and failure behavior. The work necessitated measurement of strength and stiffness over a wide temperature range, with interesting results up to the point of resin decomposition. The approach was applied to three 12 mm thick glass reinforced systems: vinyl ester, polyester, and polypropylene. The laminates were subjected to a one-sided 50 kW·m⁻² heat flux, using a propane burner. Thermal behavior was modeled using a simplified version of the Henderson equation to predict the evolution of temperature and residual resin content through the thickness. These parameters were then used, along with a material model, to predict the mechanical response in fire.

This paper relates to the expanding use of non-metallic materials in piping for the transport of oilfield fluids, onshore and offshore. Qualification processes for thermoplastic and composite pipework all involve long term stress rupture tests to establish a relationship between pressure and time to failure. These qualification tests are needed to account for particular long term failure process that occur in non-metallics, and are essential to the successful application of these materials. Uses of both thermoplastics and composites in several types of pipework are discussed. These include fibreglass pipe, spoolable thermosets, reinforced thermoplastic pipe, flexible risers, rigid risers and, finally, repair and rehabilitation.