三维四向编织复合材料结构的计算机仿真

Computer simulation of 3D four directional braided composites structure

为了在分析三维编织复合材料的编织结构时,使三维编织预制体结构仿真分析更加接近真实的情况,以三维四向编织复合材料为研究对象,假设编织纱线的截面为椭圆形,结合四步法编织原理和三维编织预制体的编织参数,对纱线的运动规律进行讨论,同时利用三次B样条曲线优化纱线的运动轨迹,并通过Matlab模拟实现;将Matlab和VS2010计算出的纱线运动轨迹的空间坐标导入到三维建模软件SolidWorks中,进行三维编织预制体结构的仿真。结果表明:当纱线间距与花节长度一定时,保持长轴半径不变,增加短轴的长度,短轴的长度越接近长轴的长度,纤维的体积分数越大;当纱线间距与花节长度一定且长轴半径小于纱线间距的1/2时,保持短轴半径不变,纤维体积分数随着长轴半径的增加而增加;当纱线的长短轴半径与纱线间距一定时,编织预制体的长度随着花节长度的增加而增加。通过以上实验,实现了编织预制体结构的可视化,有利于之后的三维编织结构研究及其力学性能分析。

In order to analyze the braided structure of three-dimensional 3D braided composites,and make the simulation analysis of 3D braided preforms closer to the real structure,3D four directional braided composites is taken as the research object,assuming that the cross-section of braided yarn is ellipse,combining the four-step braiding principle and the braiding parameters of 3D braided preform,the yarn movement is discussed,and the motion trajectory of the yarn is optimized by using cubic B-spline curve,which is realized by Matlab.The space coordinates of yarn trajectory calculated by Matlab and VS2010 are imported into SolidWorks to realize the simulation of 3D braided preform structure.The results show that when the yarn distance and the pitch length are constant,the long axis radius is kept constant,and the length of the short axis is closer to the length of the long axis,and the fiber volume fraction increases with the increase of the short axis length.When the yarn distance and the pitch length are constant and the major axis radius is less than half of the yarn spacing,the short axis radius is kept constant,and the fiber volume fraction increases as the long axis radius increases.When the length of the long and short axes of the yarn and the yarn distance are constant,the length of the braided preform increases as the pitch length increases.Through the above experiments,the visualization of the braided preform structure is realized,which is beneficial to the subsequent 3D braided structure research and mechanical property analysis.