Abstract: It is well known that the structure of preform is one of key factors for mechanical performance of three-dimension braided composite. In this paper, according to the yarn’s regulation of four-step braiding pattern, a yarn unit model is presented which is of benefit to computer graphic modeling. At the same time, using Visual C⁺⁺ and SolidWorks API, the software is programmed which can automatically generate the integral geometric structure of three-dimension braided performs. As a result, inputting different braided parameters, such as braided angle, fraction volume of fiber, yarn radius and different number of rows and columns, the software can automatically generate the braided entity. The three-dimension braided preforms with braided angle 22°, 33°; fraction volume of fiber 40%, 30%; number of rows and columns 2×2, 2×4, 4×4, 4×6 are simulated. The simulated results are well in correspondence with the practical preforms. It helps to investigate the microstructure in three-dimension braided preforms. And then, it is the foundation to establish the mechanical model for finite element analysis.

Key words: three-dimension braided composites, computer simulation, yarn unit model