三维织造层间增强的纤维棒复合材料细观结构模型及力学性能有限元模拟
Microscopic structure model and finite element simulation of mechanical properties of fiber-bar composites reinforced by three dimensional weaving

针对复合材料层间增强的需求, 提出了一种三维织造层间增强的纤维棒复合材料几何结构, 建立了0°/90°、45°/135°及 0°/90°/45°/135° 3种织造方案下的复合材料单胞有限元模型, 该模型能较为真实地反映织造物内纤维束与纤维棒的交织特征。通过施加周期性位移边界条件, 利用该模型采用有限元方法得到了3种织造方案下复合材料的等效弹性性能参数, 讨论了复合材料弹性性能与织造方案和纱线填充因子的关系, 分析了在单向拉伸载荷下3种织造方案单胞的细观应力场分布, 制作了实体模型, 进行了相关实验。结果表明: 单胞有限元模型的模拟结果与实验结果吻合较好, 织造复合材料各弹性常数对纱线填充因子变化的敏感度不同, 不同织造方案的复合材料具有不同的力学性能特征, 其主要影响因素为纤维束在复合材料内部的排列方式。给出了3种织造模型单胞的应力场分布, 为三维织造层间增强的纤维棒复合材料的结构优化提供了依据。 Aiming at the requirement of interlaminar reinforcing of composites, the geometrical structure of fiber-bar composites reinforced by three dimensional weaving was proposed. Three single-cell finite element models based on 0°/90°, 45°/135° and 0°/90°/45°/135° weaving schemes were presented respectively, which can really reflect the mutual squeezing of fiber bundles and fiber-bars in weaving fabrics. Coupled with the periodical displacement boundary condition, the equivalent elastic property parameters of composites based on three different weaving schemes were predicted by the single-cell finite element model. The relationship of elastic properties of composites with weaving scheme and yarn packing factor were studied. The microscopic stress field distributions of single cell based on three different weaving schemes under uniaxial tensile load were analyzed. Several qualified models were made and relevant tests were performed. Results indicate that simulation results obtained by single-cell finite element model make well agreement with the experimental results. The yarn packing factor makes different effect on the elastic constants of the weaving composites. The mechanical properties of composites also vary as the difference of weaving schemes, which mainly result from the arrangement of fiber bundles inside fabrics based on different weaving schemes. The stress field distributions of three weaving single-cell models were exhibited, which provide basis for the fabrics optimization of the fiber-bar composites reinforced by three dimensional weaving. 国家自然科学基金(51035003)