尺寸不规则度梯度分布参数对泡沫金属单轴拉伸力学性能的影响研究

采用数值模拟的方法,定量研究了尺寸不规则度参数为连续梯度分布时,泡沫金属在单轴拉伸下的力学性能;通过对比形状不规则度相同但尺寸不规则度不同的模型结果,明确了尺寸不规则度是影响泡沫金属力学性能的重要因素。结果表明,不规则度连续梯度变化的3D Voronoi模型是横观各向同性材料,单轴拉伸时胞孔局部变形显著;梯度参数影响梯度方向和非梯度方向的力学性能,且对梯度方向的单轴拉伸屈服强度和破坏强度尤其突出,呈二次函数关系,存在最优解。通过对比尺寸不规则度不同但形状不规则度相同的3D Voronoi模型单轴拉伸力学性能,发现梯度方向比非梯度方向的屈服强度和破坏强度受尺寸不规则度的影响更明显,不同于单轴压缩,尺寸不规则度参数是影响单轴拉伸力学性能的重要细观结构参数。对细观结构对多胞材料力学性能的影响研究进行了完善,有助于多胞材料的优化设计。

Effect of Gradient Distribution of Size Irregularity on Uniaxial Tensile Mechanical Properties of Metalic Foam

Numerical simulation method is used to quantitatively study the mechanical properties of metallic foam under uniaxial tension when the size irregularity parameter is a continuous gradient distribution.By comparing the results of the model with the same shape irregularity but different size irregularities,it is clear the size irregularity is the important factor affecting the mechanical properties of the metallic foam.The results show that the model with continuous gradient of irregularity exhibits transverse isotropy,and the local deformation of the cell is observed during uniaxial tension.The gradient parameters affect the mechanical properties of the gradient direction and the non-gradient direction,and the uniaxial tensile yield stress and the fracture stress of the gradient direction are particularly prominent,showing a quadratic function relationship,and there is an optimal solution.Comparing the uniaxial tensile mechanical properties of the 3D Voronoi model with different size irregularity but the same shape irregularity,the yield stress and the failure stress of the gradient direction are more affected by the size irregularity than the non-gradient direction,which is different from the uniaxial compression.The size irregularity parameter is an important meso-structural parameter that affects the uniaxial tensile mechanical properties.This paper improves the study of the influence of mesostructure on the mechanical properties of multi-cell materials,and contributes to the optimization design of multi-cell materials.