【摘要】 以空心规则14面体周期模型为参照,结合实际泡沫材料中出现的胞体形状及胞体排列的不规则特性,引入不规则14面胞体随机变形参数及胞体随机排列指数,得到不规则14面体部分不连续/重叠有限元模型;同时,假定短纤随机分布于胞壁和胞杆之中,纤维长度随机分布密度函数为Maxwell分布,纤维空间取向角随机分布密度函数为正态分布,建立了短纤维分布的随机模型。最后,利用不规则14面体部分不连续/重叠模型分析了胞壁厚度随机变化、胞杆截面任意三角形边长的随机变化、胞体随机形变、胞体随机排列及纤维增强等因素对弹性模量的影响,并与其它相关研究结果进行了比较,说明了本模型的优点和有效性。更多还原

【Abstract】 Based on periodic tetrakaidecahedrons,the finite element models with short-fiber reinforcement are proposed to examine the effects of the fiber reinforcement and irregular cell shape/strut variations and irregular pa-cking on elastic modulus.The fiber length distribution and fiber orientation distribution are considered.The proposed models are featured in a three-dimensional diorama with random short-fiber distribution within or on the surfaces of the walls and edges of the closed-cells of foams and the fiber length/orientation distributions are modeled by Maxwell/Gaussian probability density functions.The irregular tetrakaidecahedral models with partially continuous/overlapped arrangement is established by adopting the Gaussian randomness of the vertex and center coordinate deformations by the reference to regular tetrakaidecahedral unit cells,and the random distributions of the thickness of a cell-wall is also taken into account.In addition,irregular one replaces the regular triangle of the cross section of an edge.The elastic moduli are investigated with irregular tetrakaidecahedral unit cells and irregular packing under various fiber volume fractions,and the results are compared with other author′s reports.The agreements verify the validity of the model.更多还原