基于确定性和随机性原理的复合材料二维孔隙模型比较

Comparison between 2-D Deterministic Model and Random Model of Voids in Composite Materials

在二维条件下,对比分析了经典的确定性模型和随机孔隙模型对含孔隙复合材料的物理模拟结果。确定性模型将含孔隙复合材料看做各向同性均匀介质,将孔隙假设为大小相同、离散均匀分布的规则形状;随机孔隙模型依据随机介质理论,采取统计学原理和方法,将孔隙看做是小尺度上的随机扰动,叠加于由基体构成的大尺度背景介质平均特性之上,可以利用空间平稳随机过程加以描述。研究发现,利用随机孔隙模型不但能够得到与真实孔隙几何相似性良好的孔隙形貌,而且基于此模型的超声衰减系数理论预测结果和实验测试结果之间的符合程度大大优于传统的确定性模型。

The principles and results were compared between the traditional 2-D deterministic model and random model of voids in the composite materials.The former assumed that all voids had regular shapes with the same size or fixed mathematical distributions distributed in isotropic homogeneous media.Based on the random medium theory,the latter investigated the random morphology of voids utilizing statistical method and characterized the elastic fluctuations from voids as small scale heterogeneities superimposed on the matrix,which is described by a spatial autocorrelation function with zero mean and some statistic parameters.It is found that,in terms of the random void model,not only good agreement of the geometry of voids between the modulations and microscopic images is observed,but also the predicted ultrasonic attenuation coefficient matches well the experimental results.It is concluded that the random void model is significantly superior to the traditional deterministic model for describing the morphology of voids in the composite materials.