We describe an algorithm for generating fiber-filled volume elements for use in computational homogenization schemes which accounts for a coupling of the fiber-length and the fiber-orientation. For prescribed fiber-length distribution and fiber-orientation tensor of second order, a maximum-entropy estimate is used to produce a fiber-length-orientation distribution which mimics real injection molded specimens, where longer fibers show a stronger alignment than shorter fibers. We derive the length-orientation closure from scratch, discuss its integration into the sequential addition and migration algorithm for generating fiber-filled microstructures for industrial volume fractions and investigate the resulting effective elastic properties. We demonstrate that accounting for the length-orientation coupling permits to match the measured Young's moduli in principal fiber direction and transverse to it more accurately than for closure approximations ignoring the length-orientation coupling.
Keywords: Length-orientation distribution coupling; Maximum entropy closure; Representative volume element; Sequential addition and migration; Short-fiber composite.
© The Author(s) 2024.