Effect of Stress on the Fire Reaction Properties of Polymer Composite Laminates

Abstract

A small-scale loading frame was used to apply tensile and compressive stresses to glass vinyl ester and glass polyester laminates in a cone calorimeter under a heat flux of 75kW m−2. It was found, for the first time, that stress has a small but significant effect on the fire reaction properties. Increasing tensile stress increased heat release rate and smoke production, while shortening the time-to-ignition. Compressive stress had the reverse effect. This was attributed to the fact that tensile stress promotes the formation of matrix microcracks, facilitating the evolution of flammable volatiles. This hypothesis is further supported by the observation that stress has the greatest effect on the early heat and smoke release peaks, with a lower effect on the final ‘run-out’ values.