Quantitative analysis of the effect of foam morphology on the quasi-static and cyclic-dynamic tensile properties

This study is the initial investigation into the relationship between the structure of foam and its quasi-static tensile and tension-tension fatigue properties. It is also the first examination of crack initiation and propagation in relation to various foam morphology patterns. The overall foam morphology and geometric appearance of the cell structure can be altered by varying the parameters of foam injection molding. Quantitative features of foam morphology are measured in terms of cell diameter, cell distance, cell density, density reduction, heterogeneity in cell size distribution, sphericity, and cell volume. Multiple linear regression with polynomial terms is used to identify which structural characteristics have the most significant impact on predicting quasi-static and cyclic-dynamic tensile properties. According to the results, the density reduction (p-value = <.0001) and cell volume (p-value = <.0001) have significant effects on the dynamic modulus. The in-situ digital image correlation (DIC) results show that cells can show self-healing by the combination of strain and temperature to blunt pre-existing cracks and prolong the crack propagation process.