Thermomechanical Response of a Thin Sandwich Composite Structure

The paper presents a stiffness evaluation as well as thermal response of a sandwich structure with thin nonwoven polyester mat as core. The structure presents dissimilar skins from which one is a glass fabric reinforced polyester. Tensile and three-point bend tests have been carried out to determine the most important features of this structure. The thermal expansions have been measured using a DIL 420 PC dilatometer from NETZSCH, on both glass fabric reinforced polyester skin and for the whole structure. The coefficients of thermal expansion have been determined only for the structureʹs upper skin. For each sample, two successive heating stages in order to size the influence of the thermal cycling, and temperature interval from 200C to 2500C, at a heating rate of 1 K/min have been used. To eliminate the system errors, the dilatometer has been calibrated by measuring a standard SiO2 specimen under identical conditions. The experimental researches accomplished on specimens show a twelve times increase of the flexural rigidity against the upper skin one.