Multi-layer polymer-metal laminate as fire protection for lightweight transport structures

PhD ThesisThis study describes the development both of a new surface thermal insulation system, the experimental investigations into its fire protection mechanism and efficacy and a new thermal response modelling program. The use of multi-layer polymer metal laminates (PML) draws on the general principle common in conventional insulation methods, such as mineral-fibre and intumescent coatings, of immobilising high fractions of gas within the material and using the gas’ low thermal conductivity, harnessing the insulating effect. PMLs have the advantage over these systems in that they also form an integral part of the structure thereby contributing to the structural performance. With the view of taking this concept from laboratory scale to manufacture, material characterisation experiments were carried out to determine thermal and expansion characteristics of the PML material as these properties significantly influence fire performance. The PML FIRE model predicts the thermal response of PML-insulated substrates and was developed to take account of PML-specific effects such as expansion and foil melting. A series of small-scale fire tests were performed over wide heat flux ranges and on various PML designs, which included variations of PML ply numbers, foil thicknesses as well as the front face appearance, in order to gain insights into the PML fire protection mechanism and to validate the PML FIRE model. Fire-structural experiments on non-reactive and combustible PML-protected substrates commonly used in lightweight structures demonstrated the lower temperature transfer and the greatly improved structural resilience of the underlying substrate achieved. Good correlation of experimental and modelled temperature curves using PML FIRE has been obtained. The thermal state of specimens during heat exposure experiments up to structural failure can now be accurately predicted. Comparison of PML against other insulation methods illustrated the PML’s equivalent or superior behaviour in reducing underlying substrate temperatures and prolonging structural life during fire-structural testing.This research was part of the FIRE-RESIST project funded as a Framework 7 program by the European Commission. I would also like to acknowledge the financial support given through the Endeavour Research Fellowship awarded by the Australian Government, Department of Education and Training

Multi-layer polymer metal laminates for the fire protection of lightweight structures

A multi-layer polymer metal laminate (PML) system is described, which can be used to thermally insulate lightweight structural materials, such as aluminium or carbon fibre reinforced plastic (CFRP) composite, when exposed to fire. The system comprises many thin adhesively-bonded metal foils, bonded directly to the structural substrate. When exposed to fire the PML adhesive thermally decomposes with the generation of volatiles, causing the foils to delaminate and inflate, thus greatly reducing its thermal conductivity. The expanded PML slows heat transfer from the fire into the structural substrate, resulting in lower temperatures and increased structural survivability. The fire protection effects of two different thicknesses of PML are demonstrated here for both aluminium and CFRP substrates. Fire exposure tests demonstrate that the substrate temperatures are reduced and the time to failure under load is substantially improved. The protection offered is equivalent or superior to conventional fire protection materials such as ceramic fibre mat or intumescent coatings. The advantage of the PML is that, in non-fire conditions, it contributes to the appearance and load-bearing capability of the structure without being prone to damage or water absorption

Model for the characterisation and design of Passive Fire Protection (PFP) systems for steel structures

High-resolution bathymetric data from the New Jersey and Californian continental margins show a marked depression running along parts of the base of the continental slope. Detailed analysis reveals that the depressions are a series of discrete ‘plunge pools’ with associated downslope topographic ramparts. We have used new bathymetric data to create our own data base (of over 150 examples) and systematically analyse plunge pool morphology and location. Previous observations of plunge pools have been sparse. Plunge pools are up to 1100 m wide and 75 m deep, with a mean diameter of 400 m and a mean depth of 21 m. Plunge pools only occur where there are sharp decreases in slope of more than 4°, and are well developed where changes in slope exceed 15°. We propose plunge pools can be created by two mechanisms. Firstly, they may be due to reduced bed shear stress downstream of hydraulic jumps in submarine sediment-laden density flows that causes the deposition of bedload and the creation of a sediment bar. This bar then defines the downslope margin of a pool. Secondly, the impact of high-momentum sediment-laden density flows can excavate a depression, as has been observed for subaerial snow avalanches. Sediment deposited downslope of these impact pools is very poorly sorted, and partly derived from erosion within the pool. Both mechanisms influence whether turbidity currents are generated from high-density sediment-laden density flows, influence whether depositional flows are channelised, and have implications for base-of-slope facies models