A novel algorithm for significantly increasing the fiber volume fraction in the reconstruction model with large fiber aspect ratio

Abstract

Geometric reconstruction is an important precondition for the computational micromechanics analysis of chopped fiber reinforced composites. When fiber aspect ratio increases, the maximum fiber volume fraction in reconstruction model reduces rapidly because of jamming limit, which greatly limits the application of reconstruction methods. A novel algorithm is proposed to significantly increase the fiber volume fraction in the reconstruction model of the chopped fiber reinforced composites with large fiber aspect ratio. The algorithm is made up of two stages. At the first stage, fibers are packed into the sublayers of initial filling space to preliminarily design fiber orientation distribution. The unidirectional arrangement of fibers is adopted to achieve high fiber volume fraction. At the second stage, a new multi-step fiber shaking strategy is used to introduce randomness into reconstruction model. The high fiber volume fraction over 30% is achieved within the wide range of fiber aspect ratio from 50 to 200 while the results of the existing methods are not more than 10%, showing the remarkable increase of the fiber volume fraction under large fiber aspect ratio. The proposed algorithm is verified by the statistical results of the four representative microstructural characteristics from reconstruction model and realistic material.