树脂基三维编织复合材料粘弹性性能的有限元分析

根据材料的细观结构,采用APDL语言分别建立了纤维束和三维编织复合材料两级单胞的参数化几何模型;推导了Prony级数表示的树脂粘弹性本构方程,对模型进行了组分材料参数设置;对纤维束单胞模型进行扫掠式网格划分,对三维编织复合材料单胞模型进行线-面-体式网格划分;对两级单胞模型均施加合理的边界条件,使单胞边界上的位移满足周期性和连续性。以有限元模型为基础,计算了三维编织复合材料的粘弹性能,并给出了材料粘弹性效应随工艺参数变化的规律。计算结果表明:三维编织复合材料编织方向的粘弹性效应随编织角的增大而增强,随纤维体积比的增大而减弱。该结果与已有实验结论一致。

Finite element analysis on viscoelastic properties of resin-based 3-D braided composites

According to the meso-structure of materials,two-scale parametric unit cell models of fiber bundles and 3-D braided composites are constructed by using the APDL programming language,respectively.The viscoelastic constitutive equation in Prony series for resin matrix is derived,and the parameters of component materials are set up.The meshing type for unit cells of fiber bundles is the Sweep in ANSYS,and the unit cells of 3-D braided composites are meshed through the steps of line-surface-body type.The reasonable boundary conditions are applied to the two-scale cell models,therefore the periodicity and continuity of displacements are satisfied on the boundary of unit cells.Based on the finite element models,the viscoelatic properties of 3-D braided composites are calculated,and the variation of viscoelastic properties with process parameters is also obtained.It is shown that with the increase of braiding angles,the viscoelastic properties in the braiding direction increase,and with the increase of fiber volume fractions,the viscoelastic properties in the braiding direction decrease,which agrees well with the experimental results.