Quantitative analysis of length-diameter distribution and cross-sectional properties of fibers from three-dimensional tomographic images

A number of rule-of-mixture micromechanical models have been successfully used to predict the mechanical properties of short fiber composites. However, in order to obtain accurate predictions, a detailed description of the internal structure of the material is required. This information is often obtained from optical microscopy of polished cross-sections of a composite. This approach gives accurate yet local results, but a rather large number of optical images have to be processed to achieve a representative description of the morphology of the material. In this work a fully automatic algorithm for estimating the length-diameter distribution of solid or hollow fibers, utilizing three-dimensional X-ray tomographic images, is presented. The method is based on a granulometric approach for fiber length distribution measurement, combined with a novel algorithm that relates cross-sectional fiber properties to fiber length. The work opens up a possibility to assess multivariate distributions of fiber length and diameter, cross-sectional area or other microstructural fiber properties. As an example, the description of the microstructure of different composites with natural fibers is presented, along with verification of the results.