In-situ full-field deformation analysis of injection-molded microcellular polycarbonate according to foam morphology patterns

Abstract

Deformation behavior of microcellular foam materials are sensitive to microstructural details. Therefore, the distinctive foam morphology patterns of foam injection-molded Polycarbonate are identified. These morphology patterns are investigated regarding their cell size, distance between cells, cell density, density reduction, homogeneity of cell size distribution, sphericity of cells and cell volume. Consequently, the predefined foam morphologies, the resulting modulus of elasticity and the elongation at break are compared to understand extensively how the deformation of foam structures depends on morphological properties. The detection and propagation of cracks are monitored using a 3D Digital Image Correlation technique. According to results, the morphology patterns which are presenting identical mechanical properties, exhibit distinctive differences during crack initiation and propagation. The highly localized strain distribution becomes more inhomogeneous beyond the yield point. Differences in the homogeneity as well as the distance between cells lead to dissimilarities in the localized high-strain fields.