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Courteau-Godmaire, Hubert

University of British Columbia

Composite forming is an intricate multi-physics process involving ply slippage, shearing, bending, and compaction within a viscous matrix. Existing simulation technologies primarily adopt shell-based modelling, often sidelining thickness effects and limiting the accuracy of ply-level defect predictions. In response to this limitation, this work integrates the Cosserat continuum (micropolar) theory, offering a mechanism-based approach to capturing the unique layered kinematics of composite layups. A Cosserat continuum extends the traditional continuum models by introducing an additional rotational degree of freedom, providing a framework for accommodating asymmetric shear behaviour and intrinsic bending observed experimentally during the forming process. This theory has been integrated into a custom-built 2D explicit finite element model in MATLAB. The model leverages high-order elements and a co-rotational edge tracking method to define material orientation. To capture the soft and highly deformable behaviours of the uncured composite materials during forming and consolidation, the model incorporates various constitutive responses such as nonlinear fibre-bed compaction, viscoelasticity, and inter-layer plastic slip. The accuracy of the model is demonstrated through extensive verification against analytical solutions and Abaqus models, affirming its robustness under large-strain and large-rotation conditions. The Cosserat-based model efficiently simulates layered structures with fewer nodes and by bypassing the need for contact algorithms, provided the macroscopic behaviour remains continuous. The model is further shown to provide its practical relevance in composite manufacturing by offering valuable insights into wrinkle formation during the consolidation of a C-Channel spar. This research represents a proof of concept, highlighting the potential of the explicit/Cosserat approach in accurately modelling the deformational response of composites during processing. Future enhancements could focus on increasing the speed of the explicit solver, or porting the methodology to a commercial platform as a user element subroutine.

Text

2023-09-28

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/86038

Civil Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/