摘要
从四步法 1× 1编织复合材料细观结构的代表性单胞模型入手 ,将预成形件划分为三个不同的区域 ,识别预成形件的两种局部单胞 (内部单胞和表面单胞 )模型 ,将单胞中的四个不同方向的纤维束看成是空间四个不同方向的单向复合材料 ,纤维束的性能可以等价于单向复合材料的宏观性能。采用复合材料中的细观力学分析方法 ,计算单向复合材料的弹性常数。认为每一纤维束的纤维体积含量与整个单胞的纤维体积含量相等。研究了三维编织复合材料代表性单胞模型的弹性常数预测 ,探寻三维编织工艺参数与力学性能之间的关系 ,利用刚度体积平均概念 ,预测三维四向编织复合材料的弹性常数 ,理论值与试验值取得了理想的吻合。
In the three-dimensional(3D) braiding process, the fibers (yarns) are braided first into a structural perform which is then impregnated with a matrix material and consolidated into the final shape. The yarn architecture of 3D braided composites products by the four-step 1×1 braiding technique and their effective elastic properties have been studied with experimental investigation and a numerical method, respectively. In the analytical approach, the effective properties of the braided yarn of the unit cells are determined first using a fabric architecture(FAM) model. The fiber volume fraction of each inclined lamina was assumed to be the same as that of the composites. Three-dimensional stress-strain analysis was applied to each unidirectional lamina that was assumed to be transversely isotropical under on-axis coordinate system. Then, the effective properties of the 4-step braided composite are predicted using an averaging technique. Structural shapes braided by the four-step 1×1 procedure are used as examples; numerical results of mechanical properties in variously braided performs are presented in explicit items of the braiding parameters. The present work provides the analytical basis for 3D braided composites.
出处
《机械强度》
CAS
CSCD
北大核心
2003年第5期504-508,共5页
Journal of Mechanical Strength
