In this paper, a parameterized unit cell model for 3D braided composites considering transverse braiding angle variation is proposed, to assist the mechanical characterization of such materials. According to the geometric characteristics of 3D braided composites, a method for automatically generating textile geometries based on practical braiding parameters, including the main braiding angle, the transverse braiding angle, and the fiber volume fraction, is established and implemented in a CAD software package. In this model, the addition of transverse braiding angle educes a more flexible control of fiber volume fraction distribution, and with the combination of control parameters according to the actual fiber distribution needs of users, it can suggest the appropriate parameters for the unit cell. The generated unit cell models are used in finite element analysis and the results are validated against experiments for a number of 3D braided composites in terms of fiber volume fraction and elastic constants, and good agreement is observed. Based on the parameterized unit cell model, the effects of main braiding parameters on the elastic properties of 3D braided composites are discussed.

An accurate method for modeling the braided preforms is vital for the mesoscopic performance analysis of tubular composites. This study proposed a high‐fidelity virtual braiding model for the general braiding process, which further considers the fiber‐level deformation of the yarns during the braiding process to generate the realistic mesostructure of preforms in tubular composites. The method uses the digital element approach previously proposed for weaving processes to model the braiding yarn. The whole braiding process, including the deposition zone and convergence zone, is incorporated into the model to account for the effect of interaction in these zones on the preform mesostructure. Two braiding processes were simulated with the proposed virtual braiding method. The simulated geometry of the braided preforms and the yarn paths in the convergence zone agree well with the reported experimental results. To facilitate the performance analysis of braided composite structures, further automated generation of solid cell instances based on the obtained braided preforms was studied. Importantly, this work could reduce the considerable effort required for characterizing the mesostructure via the costly micro‐CT scans for braided composites, and the generated geometry of the braided preform is more precise than the widely used highly idealized models.