Experimental study and numerical prediction of the elastic properties of syntactic foams considering the interfacial effect
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摘要: 通过对不同空心陶瓷微珠含量的环氧基复合泡沫塑料进行准静态拉伸实验, 研究了填充微珠的体积分数对复合泡沫塑料弹性模量和泊松比的影响。基于其细观结构特征, 利用三维立方单胞有限元模型模拟了细观应力/应变场; 将内聚力单元引入细观有限元模型, 以此来模拟空心微珠与基体材料之间界面相的力学行为。将有限元预测结果以及两种传统的细观解析法与实验数据对比, 发现基于界面理想粘接假设的有限元模型和传统细观解析法均过高估计了复合泡沫塑料的弹性模量和泊松比; 复合泡沫塑料的弹性性能强烈地依赖于界面相的力学性质, 只有考虑界面效应的细观有限元模型才能给出较为精确的预测, 从而验证了文中细观建模方法的合理性。Abstract: Quasi-static tensile experiments were performed on the epoxy-based syntactic foams filled by hollow ceramic microspheres with different volume fractions in this study. The effects of microspheres volume fraction on the Young's modulus and Poisson's ratio of syntactic foams were investigated. Microstructure based three-dimensional unit cell models were constructed to capture the stress/strain fields in mesoscale. Cohesive elements were introduced to the FE model to simulate the mechanical behavior of the interface between the microspheres and the matrix material. To verify the validity of the proposed model considering the interface effect, numerical results and two classical analytical methods were compared with the experimental data. It can be found that the ideal interfacial bonding hypothesis based FE model and the classical analytical methods seriously overestimates the experimentally determined Young's modulus and Poisson's ratio. The elastic properties of syntactic foams heavily depend on the mechanical properties of the interface, and only the results obtained by the FE model considering the interfacial effect are much closer to the experimental values and thus provide more accurate predictions.
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Keywords:
- syntactic foams /
- computational mesomechanics /
- interface /
- cohesive element /
- finite element method
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