Fiber-reinforced epoxy composites exposed to high temperature environments. Part II: modeling mechanical property degradation

Abstract

This article is part of a series on the thermo-mechanical responses of fiber-reinforced composites at elevated temperatures and it follows the first part containing experimental results. A flame-retardant system consisting of a cellulosic charring agent and an interactive intumescent additive (melamine phosphate) has been used in order to improve the post-fire mechanical performance of glass fiber-reinforced epoxy composites. The effect of one-sided radiant heat on the residual flexural stiffness of laminate coupons exposed to incident heat fluxes of 25 and 35 kW m À2 was investigated. The flame-retarded coupons retained a higher percentage of their original room temperature flexural modulus after heat exposure while the control specimens showed inferior material property retention over the same exposure periods. A heat transfer (thermal) model based on Henderson's equation is used to predict the through thickness temperature profiles and subsequently the mass loss due to the resin matrix decomposition at elevated temperatures. The theoretical results from the heat transfer model are validated against experimentally obtained data and then coupled with a mechanics model that describes material property-temperature dependence in order to predict the residual flexural stiffness, after heat damage. The accuracy of the thermo-mechanical model was validated against the experimental data and a good agreement was observed.

Modelling flaming combustion in glass fibre-reinforced composite laminates

“…For validation of models discussed in subsequent sections, eight ply glass -fibre reinforced composite laminates were fabricated via a wet lay-up method using a low-viscosity and low temperature-curing base epoxy resin containing 1,4-butanediol diglycidylether, (Araldite LY5052) and a hardener based on modified cycloaliphatic amines (HY5052) (Huntsman, Inc.); woven roving E glass (300 g/m 2 ) (Glasplies, 5 UK). The composite fabrication details are given elsewhere [13]. Two types of composite laminates were prepared; a control (EP) and a fire-retarded sample (EP20) containing 20% w/w fire retardant additives in the resin.…”

“…This work presents further refinement of our recently developed heat transfer model, Kandare et. al., [13], based on Henderson's equation, which predicts the through-thickness temperatures of the laminates exposed to radiant heat, but only prior to ignition of the laminate. The refinement allows measurement of time and temperature of ignition, and through-thickness temperature profiles of the burning laminates.…”

Simulation of Thermal Behavior of Glass Fiber/Phenolic Composites Exposed to Heat Flux on One Side

“…Furthermore, Henderson and Wiecek [9,10] improved the 1D thermal model to predict the thermal behavior of the composite material, taking into account the thermochemical expansion [11] in the depth orientation of the sample, as well as the flow and accumulation of decomposition gases. Gibson and Mouritz et al [12][13][14][15][16], Kandare [17], Desjardin [18], Summers et al [19], and Bhat et al [20,21] further improved the pyrolysis kinetic model for thermal analysis of composite laminates in a fire environment. Anjang et al [22] developed a thermal model for sandwich composites by improving the Henderson and Gibson models.…”

Thermal Protection of Carbon Fiber-Reinforced Composites by Ceramic Particles

“…The thermal and fire performances of fiber-reinforced composites depend upon the resin and fiber type, their mass/volume fraction composition and fiber configuration [1,2]. When exposed to high heat fluxes, the heat transfer and the resulting temperature rise through the thicknesses of samples depend on the density, thermal conductivity, and specific heat capacity values of both the resin and fiber components, as well as the kinetics of their decomposition [3][4][5], although the latter is applicable to resins only in the case of these composites. The thermal and mechanical performance of most thermosetting resins is dictated by their functionality.…”