Computational Design of Fibre Network by Discrete Element Method

Soft fibre networks, typically seen in bathroom tissues, kitchen towels, and personal-care products, have properties that are intricately affected by the details of fibre geometry, 3D-network structures, and processing conditions. Designing such materials and products for better performance, while controlling cost, is especially a challenge in today’s fast paced product development. This paper concerns the development of a new, robust computational design platform for the design of soft fibre networks. We have used particle-based methods, particularly, Discrete Element Method (DEM), to model fibres, fibre networks, their properties and performance, and also unit processes for manufacturing. Unlike other computational methods, this method has advantages to model discrete and non-homogeneous materials, complex geometries, and highly non-linear dynamic problems, such as large deformation (flow), contact/non/contact, fracture, and fragmentation. With this approach, fibres are represented by a series of connected spherical particles in different lengths and geometries (curl, kinks, twists). Fiber networks are created by the deposition of those fibres under gravity, followed by the subsequent consolidation under pressure. here processes have shown an interesting transition phenomenon from a highly fluidic granular system to a fragile soft solid. The network is then subjected to a creping process, a critical process of tissue-making. The model was able, not only to reproduce unique crepe frequencies, but also unprecedented details of the destruction of fibre network structures and fibre failure (dusting) during creping. Typical tensile tests, thickness-direction compression tests, and softness tests have been also performed to demonstrate unique deformation characteristics of low-density, low-basis weight fibre networks. This computational design system based on DEM provides a promising platform for exploring large parameter space of new material/product design.