Prediction of mechanical properties of 3D tubular braided composites at different temperatures using a multi-scale modeling framework based on micro-CT

It is of great significance to establish a real three-dimensional (3D) tubular braided composites mechanical properties prediction model at different temperatures. In this paper, a multi-scale modeling framework based on micro-computed tomography (micro-CT) is adopted to consider the characteristics of the real yarn cross section, fiber shape deviation and internal defects within the matrix after composite formation, and a realistic trans-scale finite element model for 3D tubular braided composite is established. The micro-scale and macro-scale mechanical properties of 3D tubular braided composites at different temperatures are sequentially simulated by using the elastic-plastic damage model considering temperature and the tractor-separation constitutive model. Comparison with experiments shows that temperature significantly affects the mechanical properties. With the increase of temperature, the overall failure degree of the 3D tubular braided composite under axial compressive load increases significantly, its axial compressive strength and modulus decrease significantly, and the post-peak response of the stress-strain curve gradually flattens. The proposed trans-scale model demonstrates high predictive accuracy.