Predicting the mechanical behavior of a polypropylene-based nonwoven using 3D microstructural simulation

Abstract

Based on filtration simulations, virtual filter media development is used to design new nonwoven microstructures with increased filtration performance. However, the processability in the subsequent manufacturing processes of these new designs is not guaranteed. The ability to predict the mechanical properties of the new designs is crucial to predict their processability. This paper introduces a microstructural simulation model based on micro-computed tomography scans (µCT scans) to predict the three-dimensional elastic-plastic behavior of nonwoven filter media with polypropylene fibers. A microstructural analysis is performed to investigate the requirements of a representative volume element (RVE). Digital twins of the µCT scans are modeled based on the microstructural analysis. The results of an RVE convergence study serve to corroborate the existence of RVEs for this kind of material. Microstructural simulations for the load cases of tension, compression, and shear in all three spatial directions are performed on µCT scans and digital twins. The calculations are validated using the results of an extensive 3D material testing program. The distinct deformation mechanisms under the load cases of tension, compression, and shear in the machine direction, cross direction, and z-direction are discussed. Finally, the results show the dependency of the effective elastic-plastic deformation behavior on a small number of selected microstructural parameters. This dependency enables the usage of digital twins to predict the deformation behavior of virtual microstructure designs.