提出了计算含界面相的单向纤维增强复合材料三维应力的二重双尺度方法。在性能预报方面,首先对界面相和纤维进行均匀化得到均匀化夹杂,然后对均匀化夹杂和基体进行均匀化得到宏观均匀材料;在应力场描述方面,从宏观均匀场出发,利用双尺度渐近展开技术经过两次应力场传递,依次得到单胞和应力集中区域的应力场。与有限元方法相结合,计算了宏观轴向均匀拉伸载荷条件下含界面相的单向纤维增强复合材料的三维应力场分布。数值结果表明在此载荷条件下最大应力发生在每根纤维的中截面内,靠近纤维与界面相的交界处。讨论了界面相性能对应力场分布的影响,结果显示纤维、界面相与基体力学性能的等差过渡有利于缓解纤维在界面附近的应力集中。
A dual two-scale method was presented for computing 3D stress fields of unidirectional-fibre reinforced composites considering the interphase.In the prediction of properties,the homogenized inclusion was obtained by homogenizing the fibre and the interphase,and the macroscopic homogenized material was obtained by homogenizing the homogenized inclusion and the matrix.In the characterization of 3D stress fields,by twice stress transmissions,the stress fields of the unit cell and the stress concentration area were obtained in turn by the two-scale asymptotic technique.Combining with the finite element method,the 3D stress fields of the proposed composites,which are under the macroscopic axial uniform tensile load,were computed by the dual two-scale method.The numerical results show that the maximum stress occurs within the region which is in the middle section of each fibre and close to the border between fibre and interphase.The influence of different interphases on the distributions of stress fields was also discussed.The results show that arithmetical transition of the properties of fibre,interphase and matrix is beneficial to releasing stress concentration.