2.5D编织复合材料细观结构及弹性性能

基于对2.5D编织复合材料细观结构的观察,提出了结构上更稳定的三维力学模型,反映了2.5D编织复合材料的结构.针对该模型,推导了纤维体积分数与几何参数之间的关系,并采用刚度平均法和有限元法预测了2.5D编织复合材料的等效力学性能,分析了弹性常数随纤维体积分数以及经密、纬密的变化规律.两种方法的预测结果均表明,倾斜角对弹性性能影响并不显著,但对材料内部的细观应力场有较大影响.理论预测与有限元结果吻合较好,从而验证了模型的有效性.

Meso-StructureandElasticPropertiesof2.5DBraidedComposites

Based on the observation of the meso-structure of 2.5D braided composites, a three-dimensional mechanical model is presented, which is more stable and is able to reflect the structure of this composites. The relationship between the fiber volume and geometric parameters is deduced by using this model. The stiffness average method (SAM) and finite element method ( FEM ) are adopted to predict the effective mechanical properties. The elastic constants varying with the change of fiber volume, warp density and weft density are analyzed. Both of the predicted resuits show the camber angle does not noticeably affect the elastic properties, but has a notable impact on the mesostress field. The theoretical prediction is in accordance with the FEM results, which verifies the validity of the model.