三维编织体复合材料空间几何结构的计算机模拟

针对四步方形编织结构,从三维编织工艺和实际的编织过程出发,提出一种单元几何模型,并通过计算机图形建模建立织物的空间几何数学模型,解决了三维编织复合材料内部编织结构分析困难的问题。该模型以携纱器循环一周返回到起始位置所形成的纱线编织结构作为单元,系统分析编织过程中纱线的空间运动规律,保证纤维束的连续性和材料整体结构的完整性。对每根纱线,选取它在编织体各个区域内合适的控制点,过这些控制点拟合成三次样条曲线,以此模拟纱线的空间结构中心线,从而能够方便直观地观察到各纱线具体走向。最后得到纱线和编织体的结构,从而便于下一步进行编织体复合材料力学性能的有限元分析。

Computer Geometry Simulation of Spatial Structure of Three-Dimensional Braided Composites

For 4-step square braiding structures,a representative geometric model of unit cell was presented through studying the actual braiding process,as well as fabrics spatial geometry model.It is composed of a series of yarns,the structure of which is formed when yarn carriers wind a full cycle and return back to the initial start position,such a model ensures continuity of yarn bunches and integrity of braided composite structure.For each yarn,control points were assigned properly in all regions of braided volume,then the cubic B-spline curves were constructed by passing these control points,forming the central axes of yarn spatial structure.Finally the structure of yarns and the braided cell was generated,which was quite suitable for the next FEM analysis of the mechanical properties of the braided composites.