Microstructural imperfections, such as fibre waviness, voids, and notches, have been reported to impact greatly the performance of fibre-reinforced composites under longitudinal compression. To investigate the effect of real microstructural imperfections, micromechanical finite element models (μFEM) have been generated using data from micro-Computed Tomography (μCT) tests. Due to the increased computational cost, conventional μFEMs with continuum 3D elements fail to simulate large enough
microstructures to be considered statistically representative. This study proposes an efficient μFEM using shell and beam elements to simulate the behaviour of the matrix and fibres respectively. The composite microstructure simulated with the Shell-Beam models uses 3D fibre paths from existing μCT experiments and represents a volume up to two orders of magnitude larger than existing μFEM in the literature. In this work, we present the methodology to construct Shell-Beam composite microstructures using fibre data from existing μCT tests and compare its results against conventional μFEMs found in the literature. The outcome showcases the benefit of using the Shell-Beam method to investigate the effect of real fibre imperfections on the behaviour of the composite under longitudinal compression.