三维四向编织复合材料弹性性能的有限元预报

在四步法方型三维编织复合材料细观结构单胞模型的基础上,假设纱线具有六边形横截面,应用ANSYS软件,建立了实体有限元模型,该模型表面与预制件表面平行,更加符合三维编织复合材料的实际结构,且有利于力学性能的分析,同时,该模型中还考虑了织物的编织角与内部编织角的几何关系.基于该模型,计算了材料的弹性常数,分析了编织角和纤维体积含量对弹性常数的影响规律.结果表明,数值计算与实验结果吻合较好.此外,还确定了材料内部的应力场分布,为材料的强度预测奠定了基础.

Finite element prediction of elastic properties of three dimensional and four directional braided composites

A new finite element solid model was established based on the unit cell model of 4-step rectangular three-dimensional braided composites and the assumption of the yarns with the hexagonal cross-section.The surface of model is parallel to the surface of perform,which coincides with the actual configuration of 3D braiding composites and is suitable for the analysis of the mechanical properties.The model also considered the relationship between braiding angle and internal braiding angle.Based on the model,the elastic constants of material were calculated by the ANSYS software and the numerical results showed good agreement with the experiment results.The influences of the braiding angle and fiber volume fraction on the elastic constants were also analyzed.The stress field of composites was determined,which provided a basis for the strength prediction.