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脆性材料的破坏通常是瞬态快速断裂,亚临界慢裂纹扩展特别是宏观慢扩展,很难在实验中观察。它一定程度上制约了玻璃陶瓷等材料的失效过程分析和阻力特性研究。本研究利用MFPA2D(Material Failure Process Analysis)软件成功地模拟了玻璃类脆性材料在平面应力状态下承受单向、双向应力时的亚临界裂纹扩展全过程,着重研究了脆性材料的慢裂纹扩展和扩展速度所受双向应力的影响,并讨论这种影响的机理和作用。通过声发射特性的数值模拟得到脆性材料在单向及双向应力状态下的亚临界裂纹扩展长度-荷载步曲线。结果表明,平行于裂纹面的拉应力对裂纹扩展有一定程度的阻碍作用,而平行于裂纹的压应力对裂纹有驱动效果。该数值实验结果与相关的实验结果取得了较好的一致,表明数值实验的可靠性,从而为脆性材料的可靠性和寿命评价提供理论基础和手段。
The failure of brittle materials is usually instantaneous rapid fracture, slow propagation of subcritical slow crack growth, especially macroscopic slow, it is difficult to observe in the experiment. It to some extent restricted the failure process analysis and resistance characteristics of glass ceramics and other materials. In this study, we used the material failure process analysis (MFPA2D) software to simulate the whole process of the subcritical crack growth of glass-based brittle materials under uniaxial and biaxial stresses under plane stress. The slow crack propagation and propagation of brittle materials Speed bi-directional stress effects, and discuss the mechanism and effect of this impact. The subcritical crack propagation length-load-step curve of brittle material under uniaxial and bidirectional stress conditions is obtained by numerical simulation of acoustic emission characteristics. The results show that the tensile stress parallel to the crack surface has a certain degree of hindering effect on the crack propagation, while the compressive stress parallel to the crack has a driving effect on the crack. The numerical results are in good agreement with the related experimental results, indicating the reliability of the numerical experiments, thus providing a theoretical basis and means for evaluating the reliability and life expectancy of brittle materials.