三维机织复合材料多尺度黏弹性分析

建立了一种三维机织复合材料多尺度的黏弹性分析模型。首先构造了微观尺度纱线束胞元和细观尺度复合材料周期结构胞元两级有限元模型, 由微观尺度胞元分析得到纱线束的弹性常数, 再代入细观尺度胞元计算出复合材料的平均弹性常数。两级胞元模型均施加周期边界条件, 保证了胞元边界上位移和应力满足周期性和连续性。随后分别建立了树脂基体和浸润树脂纱线束的蠕变模型, 用实验标定树脂的蠕变参数, 代入微观尺度胞元进行蠕变计算来修正纱线束蠕变模型的参数。最后将树脂和纱线束的蠕变本构关系应用于细观尺度胞元, 得到材料宏观平均的应力-应变响应, 模拟了三维机织复合材料的蠕变实验曲线。本文模型对于该种复合材料弹性常数和蠕变性能的预测, 均与实验吻合。 

Multiple scale viscoelastic analysis of 3D woven composite materials

A multiple scale viscoelastic model for the 3D woven composites was suggested. Firstly, the repeated unit cells, representing periodic distributions of fibers in a yarn and periodic weave architecture in composite, were constructed. They are named micro scale cell and meso scale cell respectively. Elastic constants of the yarn were obtained by analysis of the micro scale cell model, and then they were used in the meso scale cell model for calculating those of 3D woven composites. The periodic boundary conditions were applied to the two scales cell models; therefore both displacements and stresses on the two cells boundaries satisfy continuum conditions. Then two viscoelastic models for the resin and fiber yarn respectively were suggested. The viscidity parameters of the resin model were determined by creep experiment for the pure resin material, and then they were adopted in the micro scale cell to rectify the viscoelastic model of the yarn. Finally, the two viscoelastic models were adopted in the meso scale cell to simulate the creep test of 3D woven composites numerically. The predictions of both elastic constants and creep curves agree well with experimental data.