布孔方式对孔洞材料宏观力学性能影响的研究

Influence of Hole Distribution on Macroscopic Mechanical Behavior of Perforated Materials

运用材料破坏过程分析MFPA2D系统,从细观力学和损伤力学角度,研究了布孔方式对孔洞材料宏观力学性能以及破坏机理的影响。在研究中,分别建立了三种含双孔、四孔以及多孔的正方形数值模型。双孔以沿试件垂直中心线重叠布置,沿试件水平中心线并列布置和沿试件对角线倾斜布置三种方式进行布孔,四孔以正方形和菱形两种布孔方式置于试件中央区域,多孔成排布置并使其相邻四孔成正方形和菱形镶嵌于试件中。然后对这三种试件分别进行了标准的单轴压缩数值试验。通过对试验结果的讨论,阐明了布孔方式对孔洞材料宏观力学行为和细观损伤机理的影响。结果表明:孔洞的相互作用既可以增强应力集中程度,也可以减弱应力集中程度;正方形布孔方式比菱形布孔方式使孔洞材料具有更高的承载能力;多孔材料的延性断裂行为是孔洞应力屏蔽作用和材料损伤局部化行为共同作用的结果。

Material Failure Process Analysis(MFPA^(2D)) code adopted to discuss the influence of hole distribution on the macroscopic mechanical behavior and failure mechanism of perforated materials from the viewpoints of microscopic mechanics and damage mechanics.Three types of numerical models containing two holes,four holes and multi-holes are established.Two holes in the square specimens are respectively placed in overlapping mode along the vertical central line,in paratactic mode along the horizontal central line and in diagonal mode along the diagonal line.Four holes are in square and rhombic forms located in the central zone of specimens.The multi-holes in rows are embedded in the specimens to make the neighboring four holes like the square and rhombic modes,then,specimens are subjected to standard uniaxial compressive numerical tests.The results indicate that the interaction between holes strengthens of weakens the stress concentration.The load-bearing capacity of specimens in the square mode of hole distribution is higher than that in the rhombic mode of hole distribution.The ductile fracture behavior of perforated materials is attributed to the jointed effects of the shielding actions and local damage behavior near the holes.