Predicting the Mechanical Response of H100 PVC Foam from Mesostructural Finite Element Analysis

Abstract

This thesis presents a mesoscale finite element (FE) framework for predicting the mechanical response and fracture behavior of Divinycell H100 foam used as a core material in sandwich structures. Stochastic multi-cell statistical volume element (SVE)s were generated using tessellation-based approaches informed by morpho logical data from literature and CT-based characterization studies. The numerical framework was calibrated against experimentally reported tensile and compressive engineering stress–strain responses using an elasto-plastic constitutive model for the foam cell walls, implemented in LS-DYNA. Following calibration, a parametric study was conducted to investigate the influence of key mesostructural parameters, including SVE size, cell shape anisotropy, varying cell equivalent diameter, and varying cell wall thickness distribution. The results showed that these parameters influence both the homogenized mechanical response and the fracture behavior of the foam. Cell shape anisotropy, in particular, showed the largest influence in observed macroscopic mechanical anisotropy. A loading configuration was implemented to investigate core-dominated fracture behavior in sandwich structures, employing a strain based element erosion criterion, inspired by double cantilever beam (DCB) tests. The developed framework successfully reproduced several experimentally observed trends and demonstrated the strong relationship between foam morphology and macroscopic response. In future work, this thesis can serve as a reference for in vestigating how morphological features affect the mechanical response of foam cores and how their implementation in the modified DCB test influences core fracture. It provides a basis for understanding, assessing, and comparing the effects of different morphological characteristics.