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摘要: 本文试图用统计方法,将金属脆性断裂的微观过程与宏观过程结合起来,把断裂理论建立于微裂纹发展动力学的统计基础上。脆性断裂实质上是在小的范性变形过程中微裂纹成核长大的非平衡统计过程和单个主裂纹的传播过程。本文导出了描述这种非平衡统计过程的微分积分方程,并从位错机理出发研究了微裂纹动力学,从而解出了微裂纹的分布函数,求出了金属试样的断裂几率,进而导出了延伸率、断裂强度、范性功、裂纹扩展力、断裂韧性、临界裂纹长度、范性-脆性转变温度以及它们的统计偏差与其它有关物理量之间的函数关系。
Abstract: A statistical approach is proposed in order to establish a connection between microscopic process and macroscopic process of brittle fracture, and an attempt is made to base the theory of brittle fracture on the statistical foundation of micro-crack kinetics.The brittle fracture is described as a non-equilibrium process in which micro-cracks nucleate and grow, and the single main crack propagates under very small plastic deformation.A differential-integral equation describing this non-equilibrium process is derived. The micro-crack kinetics is studied from the dislocation mechanism. The statistical distribution function of micro-cracks and the fracture probability of metal sample are obtained, and thus the elongation, brittle strength, ductile work, fracture toughness, critical crack length, ductile-brittle transition temperature and their statistical deviation are all deduced theoretically.