基于三维流场模型的含孔隙复合材料弹性常数有限元预测模型

A finite element method on elastic properties of composites with voids based on 3D flow field

为预测含孔隙复合材料单向层合板的有效弹性常数,基于孔隙周边纤维分布和形态与三维Rankine椭圆体绕流流场的相似性,提出了一种基于三维Rankine椭圆体绕流流场比拟的含孔隙复合材料弹性常数计算模型与方法。建立了含孔隙复合材料的有限元单胞计算模型,用流场的速度变化比拟单胞内纤维体积分数的变化,用流线形状比拟孔隙周边纤维的形态。通过对单胞施加周期性边界条件,结合孔隙形态的概率分布模型和刚度平均法,计算了含孔隙复合材料单向层合板的弹性常数。计算结果与实验数据有较好的一致性,数值计算可以有效反映孔隙对复合材料单向层合板弹性常数的影响。

A new method was presented to predict the effective elastic constants of unidirectional continuous fiber reinforced composites containing voids of various characteristics based on the similarity between the deformation of the fibers around the voids and the flow field around the 3D Rankine oval.A finite element model of the representative volume cell was proposed,in which the volume fraction change of the fibers around the voids was described by the velocity variation in the flow field,and the direction of the fibers around the voids was described by the streamline shape.The periodic boundary conditions were used to calculate the laminar elastic properties,combining with the probability distribution model of the void shape and the stiffness volume average method.The numerical results agree reasonably with the available experimental data,which validates the computational method in the prediction of the voids influence on the elastic properties of the unidirectional continuous fiber reinforced composites.