Numerical and experimental research on polyisocyanurate foam

The researched polyisocyanurate foam FENIX is an innovative expanded structural material constituted of fine open cells suitable for transports, aeronautics, marine industries and for all those areas that require materials with strong fire reaction. In the paper the FENIX foam behaviour during quasi-static compression tests was examined. The experimental research was carried out with the use of the material testing stage which is an integral part of the microtomograph Skyscan 1147. The very interesting phenomenon was observed during experiment. Both types of researched foam showed an auxetic behaviour – the samples collapsed inside their volume, what resulted in their negative Poisson’s ratios. xt step of such material structure research was its microstrutural model development. The model was based on the well known Kelvin geometry and solid eight-node elements. The aim of the numerical study was to examine if the dimension of the sample influence its auxetic or non-auxetic behaviour. For that purpose three models built of 3 × 3 × 3, 3 × 3 × 6 and 3 × 3 × 9 cells were prepared and subjected to the compression load. Numerical analyses were carried out with the use of LS-Dyna computer code. Material characteristics and model for solid polyisocyanurate were chosen on the base of literature studies. The strain–stress results of numerical analyses were compared to the experiment with good accordance. The deformations were then examined. The samples showed an auxetic behaviour only for the 3 × 3 × 3 cells model.