中文摘要：

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．

英文摘要：

The elastic parameters, such as Young＇s modulus, Poisson＇s ratio, bulk modulus and shear modulus of rubber foams are important variables for mechanical performance characterization, and are usually employed by engineering structure designers. Because the macro-mechanical performances of foams are mainly determined by their microstructures and cell material properties, the three dimensional （3D） micromechanical foam models are constructed according to the microstructure of real silicone rubber foams and used to study the elastic performances of rubber foams with medium porosity. By means of the Abaqus software, the large compressive deformations of rubber foams are simulated, and their Young＇s modulus, shear modulus, bulk modulus and Poisson＇s ratio are calculated based upon the results of com- pressive displacement and homogenized stress under small deformation. Then the phenomenological consti- tutive models of the elastic parameters of rubber foams with medium porosity against relative density are fitted. The studies indicate that the stiffness of foam mierostructure is inhomogeneous due to the random distribution of cells. It is clear that cells of lower rigidity are easier to collapse under compressive loadings, so local collapse of some cells does not stop until foams become fully densified under compressive deforma- tion; and since the buckling plateau section becomes indistinctive, the universal three deformation regions reduce to two stages： an initial linear elastic response and a final densification stage. Research on the phe- nomenological constitutive models of foam elastic parameters shows that the random models behave isotro- pically. The predicted results of the constitutive models in this study are consistent with the theoretical ones, and agree well with the experimental data. It reveals that the phenomenological constitutive models can well predict the elastic performances of rubber foams with medium porosity; and the methods to estab- lish the micromechanical models as well as the