基于有限元压缩方法的复合材料RVE创建

AN EFFICIENT FE COMPRESSION METHOD FOR GENERATING THE RVES OF COMPOSITES

文章提出一种有限元压缩方法,可以简单、高效地创建具有较高增强体体积分数的复合材料代表性体胞单元(RVE),其具体步骤如下:(1)基于随机顺序吸附(RSA)法生成具有较低增强体体积分数的复合材料周期性RVE;(2)在周期性边界条件约束下,采用有限元方法压缩前述创建的低增强体体积分数复合材料周期性RVE,得到有限元网格格式、具有较高增强体体积分数的复合材料周期性RVE;(3)通过后处理提取得到的高增强体体积分数复合材料周期性RVE中所有增强体的位置(和取向),进而创建CAD格式的复合材料周期性RVE.采用提出的有限元压缩方法,成功创建了体积分数达50.0%的球形增强体复合材料的周期性RVE.采用最近邻距离的概率分布函数、最近邻取向角的累积概率分布函数、Ripleys-K函数和对关联函数对创建的复合材料周期性RVE中球形增强体分布规律进行了统计分析,发现创建的复合材料周期性RVE中球形增强体空间随机分布.基于创建的复合材料周期性RVE和有限元均质法预测了不同类型的球形增强体复合材料的弹性性能,并与实验测试和双夹杂模型预测的结果进行了对比,验证了创建的复合材料周期性RVE及提出的有限元压缩方法的有效性.

This work proposes an finite element(FE)compression method to establish periodic representative volume elements(RVEs)of composites with high inclusion volume fractions efficiently and simply.The main procedures of the proposed FE compression method are given as follows:(1)Generation of the RVEs of composites with periodic and sparse inclusions using the random sequential absorption(RSA)algorithm,(2)FE compression of the generated periodic and sparse RVEs in step-1 to obtain the RVEs of composites with periodic and packed inclusions(in the FE mesh format)under the constrain of a periodic boundary condition,and(3)postprocessing to obtain the centroids(and orientation)of all the inclusions in the compressed RVEs with periodic and packed inclusions and generate the periodic RVEs of composites in the CAD format.Based on the proposed FE compression method,the periodic RVEs of spherical inclusions composites with the inclusion volume fraction up to 50.0%are generated.The distribution of the spherical inclusions in the generated periodic RVEs of composites is analyzed using the probability distribution function of nearest neighbor distance,the cumulative probability distribution function of nearest neighbor orientation angle,the Ripleys-K function and the pair correlation function,and the results show that the distribution of the inclusions in the generated periodic RVEs of composites is completely spatial and random.The elastic properties of different types of composites are homogenized using the FE homogenization method based on the generated periodic RVEs,and are then compared with those of the double-inclusion model and available experimental tests.It is observed that the elastic properties of the studied composites obtained using the FE homogenization method based on the generated periodic RVEs,the experimental tests and the double-inclusion model agree well,and it thus concludes that the proposed FE compression method is capable of generating the RVEs of composites with high inclusion volume fractions.