Modelling of the compressive behavior of 3D braided tubular composites by a novel unit cell

This paper presents a novel fan-shaped unit cell model composed of curved braiding yarns to analyze the compressive behavior of 3D braided tubular composites. A geometric modeling method that integrates both the inner and outer surface cells of tubular composites into a single unit cell is firstly established and parameterized. Based on the developed boundary conditions for the adopted unit cell and existing damage modelling techniques, this computational model is able to predict the compressive properties of 3D braided tubular composites directly from the manufacturing parameters with a significant computational saving, which is advantageous for the design and analysis of 3D braided tubular composites. The results are compared with the experiment and other numerical results. The predicted stress–strain curve, failure mode, and the fracture morphology are in good agreement with experiments. Using this parameterized unit cell model, effects of braiding parameters on longitudinal modulus of 3D braided composite tubes are discussed.