三维多向编织复合材料T型梁抗弯应力分析

Study on flexural stress of T beam of 3-D multidirectional braided composites

针对三维多向编织复合材料结构件承载细观结构优化设计的问题,以三维编织复合材料T型梁为对象,对其抗弯性能进行模拟分析。基于细观结构单胞模型,采用刚度体积平均法计算具有不同编织角的三维四向、五向和六向编织复合材料的弹性常数;利用有限元软件Patran/Nastran计算T型梁承受弯曲载荷的应力应变,分析纤维束交织结构和细观结构参数对T型梁抗弯性能的影响。结果表明,纤维体积含量一定时,三维六向较三维四向、五向编织复合材料的弹性性能更接近各向同性,同时选择比较大的编织角,可提高T型梁抗弯的承载能力。此方法可为异型三维编织复合材料构件细观结构的选型与参数设计提供参考。

To optimize the microstructure design of the load bearing assembly of 3-D multidirectional braided composites, the flexure properties of three dimensional multidirectional braided composites T beam were simulated and analyzed. Based on the fine structure unit cell model, the elastic constants of 3-D, 4-, 5-, and 6 directional braided composites with different braiding angles were calculated by stiffness volume average method. The stress and strain of 3-D multidirectional braided composites T beam were computed by utilizing FEM Patran/Nastran software. The effects of fiber interlaced topology and microstrueture parameters on the bending resistance of the composites were discussed. The resuhs show that when the fiber volume content is fixed, the elasticit of 3-D six-directional braided composites is more close to isotropic when compared with 3-D 4- or 5- directional ones. Also, bigger braiding angle improves the bearing ability of the T beam. This method can be used as a reference for the microstructure design of 3-D shaped braided composites.