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首页> 外文会议>International Symposium on Metastable and Nano-Materials(ISMANAM-2005); 20050703-07; Paris(FR) >A unified study of crack propagation in amorphous silica: Using experiments and simulations
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A unified study of crack propagation in amorphous silica: Using experiments and simulations

机译：非晶态二氧化硅中裂纹扩展的统一研究：使用实验和模拟

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摘要

Atomistic aspects of dynamic fracture in amorphous silica are investigated with molecular dynamics (MD) simulations. Simulations on amorphous silica were performed for two system sizes, 15 million and 113 million atoms. Crack propagation in these systems is accompanied by nucleation and growth of nanometer scale cavities up to 20 nm ahead of the crack tip. Cavities coalesce and merge with the advancing crack to cause mechanical failure. This scenario was also observed experimentally during stress corrosion ultra-slow fracture of glass using atomic force microscopy (F. Celarie et al, Phys. Rev. Lett. 90 (2003) 075504; S. Prades, D. Bonamy, D. Dalmas, E. Bouchaud, C. Guillot, Int. J. Sol. Struct. 42 (2004) 637). This mechanism has macroscopic consequences in terms of sample life-time and deformation field. The morphology of the fracture surfaces has also been studied by calculating the height-height correlation function. In general experiments reveal two universal roughness exponents, 0.5 for small length scales and 0.8 for large length scales. The MD simulations of the 15 million and 113 million atoms system find the first roughness exponent (0.5), but the second exponent (0.8) occurs over length scales inaccessible to MD simulations. Finally, the 113 million atoms simulation was used to map out the morphology and dynamics of the whole crack front.
机译：通过分子动力学（MD）模拟研究了非晶态二氧化硅中动态断裂的原子性。在两种体系尺寸（1500万和1.13亿个原子）上进行了无定形二氧化硅的模拟。在这些系统中，裂纹的传播伴随着成核和纳米级腔的生长，而纳米级腔在裂纹尖端之前可达20 nm。空腔聚结并与前进的裂纹合并，从而导致机械故障。还使用原子力显微镜在玻璃的应力腐蚀超慢断裂过程中通过实验观察到了这种情况（F.Celarie等人，Phys.Rev.Lett.90（2003）075504; S.Prades，D.Bonamy，D.Dalmas， E.Bouchaud，C.Guillot，Int.J.Sol.Struct.42（2004）637）。就样品寿命和变形场而言，这种机理具有宏观后果。还通过计算高度-高度相关函数来研究断裂表面的形态。一般而言，实验揭示了两个通用的粗糙度指数，小尺寸为0.5，大尺寸为0.8。 1500万和1.13亿原子系统的MD模拟找到第一个粗糙度指数（0.5），但是第二个指数（0.8）出现在MD模拟无法达到的长度范围内。最后，使用1.13亿个原子模拟来绘制整个裂纹前沿的形貌和动力学。

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