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泡沫材料的宏观力学性能主要取决于基体材料的力学特性及其微细观结构特征,基于细观力学模型的分析方法是泡沫材料力学性能研究的重要途径.文中构建了描述中等孔隙率开孔弹性泡沫材料微结构特征的三维随机分布球形泡孔模型,并采用有限元方法对弹性泡沫压缩变形进行了模拟,并计算给出了不同孔隙率弹性泡沫材料弹性模量、剪切模量、体积模量以及泊松比的分布,建立了相应的唯象表达式.研究表明,泡孔分布的随机性导致泡沫材料微结构刚度分布不均匀,泡沫压缩变形过程中不断发生局部泡孔坍塌现象直至密实,使得泡沫材料的宏观压缩应力应变曲线没有明显的平台段.泡沫材料弹性参数唯象模型的研究显示,该模型预测结果与理论模型一致,且与测试结果吻合,论文建立的唯象表达式能够很好地预测泡沫材料的弹性力学性能.
The macroscopic mechanical properties of foams mainly depend on the mechanical properties of the matrix material and the microstructure characteristics of the foams, and the analysis method based on mesomechanical models is an important way to study the mechanical properties of foams.In this paper, The three-dimensional random distribution spherical cell model of the microstructure characteristics of the material was used. The compression deformation of the elastic foam was simulated by the finite element method. The elastic modulus, shear modulus, bulk modulus And the Poisson’s ratio distribution, the corresponding phenomenological expressions have been established.The research shows that the random distribution of the cell distribution leads to the uneven distribution of the stiffness of the foam micro-structure, the local cell collapse phenomenon continues to occur during the process of foam compression deformation, So that the macroscopic compressive stress-strain curve of the foam has no obvious platform segment.The research on the phenomenological model of foam elastic parameters shows that the model predictions are consistent with the theoretical models and consistent with the test results.The phenomenological expressions established in this paper can be very good Good prediction of the elastic properties of foams.