Influence of random pore defects on failure mode and mechanical properties of SiC ceramics under uniaxial compression using discrete element method
Influence of random pore defects on failure mode and mechanical properties of SiC ceramics under uniaxial compression using discrete element method
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DOI：
10.1016/j.ceramint.2018.08.349
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发表时间：
2018-12
影响因子：
5.2
通讯作者：
X. Li;Shengqiang Jiang;Ye Ying;Liu Sisi;Xu Zhiqiang;Yuanqiang Tan;Dongmin Yang
中科院分区：
文献类型：
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作者：
X. Li;Shengqiang Jiang;Ye Ying;Liu Sisi;Xu Zhiqiang;Yuanqiang Tan;Dongmin Yang
为了研究陶瓷材料中微观缺陷与宏观力学性能和行为的关系，采用离散单元法建立了随机取向椭圆形气孔的碳化硅陶瓷的计算模型。研究了单轴压缩条件下，孔洞缺陷含量及其长径比对试件破坏模式、应力应变曲线和力学性能的影响。在不同的孔洞缺陷密度下，将DEM模拟得到的有效杨氏模数与Mori-Tanaka格式(MTS)和自洽格式(SCS)的预测结果进行了比较。结果表明，随着孔洞缺陷含量的增加，材料的抗压强度和起裂应力呈非线性下降。此外，椭圆形气孔缺陷的长径比越小，弱化趋势越明显。随着孔洞缺陷含量的增加，试件的破坏模式由脆性断裂向拉剪混合再向轴向劈裂转变。应力-应变曲线在加载过程中表现出一定的“软化期”。由DEM模拟得到的有效杨氏模数与MTS和SCS在低孔道密度下的近似值吻合。然而，当孔洞缺陷密度变大时，DEM模拟结果略低于仅考虑缺陷间弱相互作用的Mori-Tanaka格式的理论结果。
To investigate the relationship between micro-defects in ceramic materials and macro mechanical properties and behaviours, a computational model of SiC ceramics with randomly oriented elliptical pores was established using the discrete element method (DEM). The effects of pore defect content and its aspect ratio on the failure mode, stress-strain curve and mechanical properties of specimen were investigated under uniaxial compression. The effective Young's modulus which was obtained from DEM simulations was compared with the predictions of Mori-Tanaka scheme (MTS) and Self-Consistent scheme (SCS) at various pore defect densities. The results showed that the compressive strength and crack initiation stress decrease nonlinearly as the pore defect content increases. Furthermore, the smaller the aspect ratio of the elliptical pore defects was, the more obvious the weakening trend was. As the pore defect content increases, the failure mode of the specimen changed from brittle fracture to tensile-shear mixing and then to axial splitting. The stress-strain curves showed a certain “softening” period during the loading process. The effective Young's modulus obtained from the DEM simulations coincides with the approximations of MTS and SCS at low pore densities. However, when the pore defect density became larger, the DEM simulation results were slightly lower than the theoretical results of the Mori-Tanaka scheme, which only considers the weak interaction between defects.