Flammability of GRP for use in ship superstructures

The effect of heat and fire on the mechanical properties and failure of polymer composite materials used in naval ship structures is investigated. Coupled thermal-mechanical models are presented for predicting the loss in strength and failure of load-bearing polymer laminates when heated from one-side. The thermal component of the models predicts the temperature and decomposition rate of a laminate. Using this information, several mechanical models based on progressive softening analysis or laminate analysis can be used to predict the reduction in strength and time-to-failure. A coupled thermal-mechanical model that is solved using finite element analysis is also presented. Experimental fire-under-load tests are performed on several types of polymer laminate materials to evaluate the accuracy of the models. The tests were performed at different heat flux levels between 10 kW/m 2 and 75 kW/ m 2 , which is equivalent to surface temperatures between about 250°C and 700°C. The temperature, mass loss and char formation of a laminate can be accurately predicted for a wide range of thermal conditions using the models. The models can also predict the time-to-failure of laminates under static tension or compression loading. The models presented in this chapter are considered useful analytical tools for naval architects to estimate the loss in mechanical performance and time-to-failure of composite ship materials in fire.

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“…[9][10][11][12][13][14][15]. Much less is known, however, about the structural response of composites to fire.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Property Degradation of Naval Composite Materials

et al. 2009

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“…However, despite the lucrative mechanical properties mentioned above, polymerbased fibre-reinforced composites for structural applications have to pass through rigorous fire safety tests especially since they are highly flammable and produce large quantities of smoke when 22 E. KANDARE, C. CHUKWUDOLUE AND B. K. KANDOLA subjected to combustion [4,5]. The most common methods of improving the fire resistance of fibrereinforced polyester composites is via the use of flame retardant additives [6,7] or intumescent paints/coatings [8,9], ceramics [10] and more recently using polymer nanocomposites [11,12].…”

Section: Introductionmentioning

confidence: 99%

The use of fire‐retardant intumescent mats for fire and heat protection of glass fibre‐reinforced polyester composites: Thermal barrier properties

2009

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SUMMARYThis study investigates the use of integral, hybrid intumescent thermal barriers (mats) to provide surface protection to the core fibre-reinforced polyester composite structural integrity when exposed to a fire or heat source. Glass fibre-reinforced composites protected by intumescent mats/fabrics containing silicate fibres, expandable graphite and in some cases borosilicate glass bounded together by an organic matrix have been evaluated for fire performance under a constant heat flux of 50 kW/m 2 . The effect of insulative fabric thickness as well as chemical composition on the flammability of the resultant hybrid composites is evaluated. Glass fibre-reinforced polyester (GRP) composites without any surface protection have a relatively higher time-to-ignition and peak heat release rate values when compared with core composites protected by insulative fabrics. Thermograms representing the variation of temperature on the reverse side of the hybrid composites with time when exposed to a constant heat flux show that the inclusion of intumescent surface barriers results in retarded temperature increments within the core GRP composites.

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“…Many of the thermal properties of composites related to fire have been thoroughly studied and are well understood, including ignition times, heat release rates, smoke production rates and gas emissions [1][2][3][4][5][6]. Also, some recent work into the post-fire residual properties showed large reductions to the edgewise compression properties of phenolic-based sandwich composites despite having good flame resistance [6].…”

Section: Introductionmentioning

confidence: 99%

Compressive Response of Composites Under Combined Fire and Compression Loading

et al. 2009

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The thermal buckling of an axially restrained composite column that is exposed to a heat flux due to fire is studied by both analytical and experimental means. The column is exposed to fire from one-side and the resulting heat damage, the charred layer formation and non-uniform transient temperature distribution are calculated by the thermal model developed by Gibson et al. (Revue de l'Institute Francais du Petrole 50:69-74, 1995). For the thermal buckling analysis, the mechanical properties of the firedamaged (charred) region are considered negligible; the degradation of the elastic properties with temperature (especially near the glass transition temperature of the matrix) in the undamaged layer, is accounted for by using experimental data for the elastic moduli. Due to the non-uniform stiffness and the effect of the ensuing thermal moment, the structure behaves like an imperfect column, and responds by bending rather than buckling in the classical Euler (bifurcation) sense. Another important effect of the non-uniform temperature is that the neutral axis moves away from the centroid of the cross section, resulting in another moment due to eccentric loading, which would tend to bend the structure away from the fire. In order to verify the mechanical response, the compressive buckling behavior of the same material subjected to simultaneous high intensity surface heating and axial compressive loading were investigated experimentally. Fire exposure was simulated by subjecting the surface of rectangular specimens to radiant heating in a cone calorimeter. Heat flux levels of 25 kW/m 2 , 50 kW/m 2 and 75 kW/m 2 were studied. All specimens exhibited buckling and subsequent catastrophic failure, even at compressive stresses as low as 3.5 MPa under a surface heat flux of 25 kW/m 2 . Details of the experimental procedure, including modifications made to a cone calorimeter to allow simultaneous mechanical loading are presented.

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Flammability of GRP for use in ship superstructures

Cited by 57 publications

References 3 publications

Mechanical Property Degradation of Naval Composite Materials

Mechanical Property Degradation of Naval Composite Materials

The use of fire‐retardant intumescent mats for fire and heat protection of glass fibre‐reinforced polyester composites: Thermal barrier properties

Compressive Response of Composites Under Combined Fire and Compression Loading

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