Discrete modelling of fibrous structure from 3D tomography images and fiber segmentation process
Lafarge Center of Research is interested in analysing the microstructure of a fibrous media and its consequence on the resulting macroscopic behavior, for optimization purposes.
ITASCA built with PFC3D a script which precisely models a fibrous structure obtained either from a mathematical algorithm developed by ESIEE, or from a 3D image analysis of a real fibrous sample led by ICMCB. This approach saves the time required to settle the fibers under gravity, numerically time consuming. Needles are modeled as of chains of spherical particles bonded together by a finite-sized piece of cementeous material resisting to both traction and flexion, a “Parallel Bond”.
A simple experimental compression test, performed in a micro-tomograph in order to track displacement and failure of each fiber, is used to calibrate the micromechanical properties of the discrete numerical model.
Discrete numerical modelling can precisely model the microstructure of a fibrous media as the 3D analysis (tomography images and fiber segmentation process) allows a good segmentation to be obtained.
Calibration of the inter- and intra-fiber stiffnesses requires simple compression tests at very small deformation, in the elastic domain.