Fraunhofer Institute for Industrial Mathematics ITWMHow does the microstructure of cellulose fibers influence liquid transport? Digital material models help to control the distribution of liquids in hygiene products and transport them more efficiently. Together with Procter & Gamble, our researchers investigated how the microscopic structure of cellulose fiber layers affects their transport properties. Using computed tomography, simulation, and GeoDict, we analyze real materials and develop virtual structure models for high-performance hygiene products.
Accessory set for Baby disposable diapers on a turquoise background tree, items for baby care. Lay diaper nappy, the parent taking care of a baby. safe baby ear sticks
In modern hygiene products, cellulose fiber layers play a crucial role: They control the distribution of liquids and support their rapid transport away, for example in diapers.
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Simulation for High-Performance Hygiene Products
Virtually Developing and Optimizing Cellulose Fiber Materials
Liquid Transport in Hygiene Products
The aim of this project, carried out in collaboration with Procter & Gamble, was to determine the effective transport properties of a cellulose fiber layer using numerical simulations. This fiber layer is one of several different layers used in modern hygiene products to distribute liquids in a targeted manner and transport them away quickly. To further improve the functionality of hygiene products through simulations, it is essential to accurately determine the permeabilities and capillary pressure–saturation curves of the individual materials and layers. In the future, virtual material design will enable the development of materials tailored to specific requirements.
Structure Models Using Geodict
To capture the fiber structure, three-dimensional computed tomography images of the layer were generated (see first figure). These 3D images were then segmented to create three-dimensional geometric structure models of the layer. Using GeoDict, the software developed at Fraunhofer ITWM, directional- and saturation-dependent permeability as well as capillary pressure curves could be calculated directly from these images. The main challenge lies in the size of the tomography datasets: A single 3D image can contain up to 4000³ voxels, corresponding to a file size of up to 60 GB.
Three-dimensional image of a cellulose fiber layer
Three-dimensional image of a cellulose fiber layer
Modell of the cellulose fiber layer with an inhomogeneous distribution of fibers created by GeoDict
Virtual Cellulose Fiber Media
However, the determination of material parameters based on CT scans is only the first step, as it only allows to investigate already existing materials. To study the impact of possible material variations on the product, virtually constructed structure models are needed. GeoDict allows to create these models (see Fig 1). In this project we investigated, how the inhomogeneous fiber distribution (as seen in Fig. 1) influences the transport properties. For this, structure models with an uniform fiber distribution were compared to structure models with fiber agglomerates.
Project partners:
Procter&Gamble