论文部分内容阅读
为研究纳米纤维增强闭孔泡沫材料的力学性能,采用Voronoi随机泡沫模型对闭孔泡沫材料的细观几何结构进行模拟,并将纳米纤维随机分布在泡沫材料的胞壁中,利用改进的自动搜索耦合(ASC)技术将纤维单元与基体单元进行耦合,建立了能够反映纳米纤维增强闭孔泡沫材料细观结构的数值模型。在此基础上,进一步研究了泡沫模型随机度、相对密度以及纳米纤维长径比和质量分数对纳米纤维增强闭孔泡沫材料弹性模量与屈服强度的影响规律。结果表明:由所建立的数值模型得到的纳米纤维增强闭孔泡沫材料的弹性模量和屈服强度与实验值吻合较好;提高泡沫模型的随机度会使复合泡沫材料的弹性模量和屈服强度增加,而当随机度达到0.450以后,材料的弹性模量和屈服强度几乎不再发生变化;当相对密度在0.05~0.30范围内变化时,复合泡沫材料的弹性模量与屈服强度几乎随相对密度的增加呈线性增长;提高纳米纤维长径比和质量分数也会使材料的弹性模量和屈服强度得到提高,但当纤维长径比达到500以后,纤维长径比的增强作用逐渐减弱。所得结论对纳米纤维增强闭孔泡沫材料的制备具有重要意义。
In order to study the mechanical properties of nanofiber-reinforced closed-cell foam, the mesoscopic geometry of closed-cell foam was simulated by Voronoi random foam model. The nanofibers were randomly distributed in the cell wall of the foam. The coupling (ASC) technique couples the fiber unit with the matrix unit and establishes a numerical model that reflects the mesostructure of the nanofiber-reinforced closed-cell foam. On this basis, the influence of randomness and relative density of foam model and the aspect ratio and mass fraction of nanofibers on the elastic modulus and yield strength of nanofiber-reinforced closed cell foam were further investigated. The results show that the elastic modulus and yield strength of the nanofiber-reinforced closed-cell foam obtained by the established numerical model are in good agreement with the experimental values. Increasing the randomness of the foam model will make the elastic modulus and yield strength When the relative density is in the range of 0.05-0.30, the elastic modulus and yield strength of the composite foam almost change with the relative density The increase of nanometer fiber’s aspect ratio and mass fraction also increase the elastic modulus and yield strength of the nanofibers. However, when the aspect ratio of nanofibers reaches 500, the enhancement of fiber’s aspect ratio decreases gradually. The conclusion is of great significance for the preparation of nano-fiber reinforced closed-cell foam.