Statistical and stochastic description of microvoid evolution observed in dynamic failure of ductile materials
Statistical and stochastic description of microvoid evolution observed in dynamic failure of ductile materials
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DOI：
10.4028/www.scientific.net/kem.177-180.1
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发表时间：
2000-01-01
期刊：
影响因子：
--
通讯作者：
Li, HL
中科院分区：
文献类型：
--
作者：
Huang, ZP;Li, HL
综述了微损伤演化的统计方法。对两种延性材料在动载荷作用下的统计微损伤演化进行了实验研究。结果表明，两种材料的微孔在尺寸和分布上存在较大差异。考虑到这一现象，将非线性速率相关材料中控制微孔成核和生长的动力学方程与空洞数平衡定律相结合，建立了描述微孔数密度演化的统计微分方程。理论解为实验观察到的现象提供了合理的解释。随后研究了受材料微观结构不均匀性影响的随机波动的影响（即随机生长模型）。在随机微分方程的基础上，导出了控制跃迁概率演化的Fokker-Planck方程。得到了转移概率的解析解，并讨论了随机波动的影响。统计分析和随机分析可以为揭示塑性材料损伤演化和动态破坏过程的物理规律提供有效的方法。
A brief review is presented of statistical approaches on microdamage evolution. An experimental study of statistical microdamage evolution in two ductile materials under dynamic loading is carried out. The observation indicates that there are large differences in size and distribution of microvoids between these two materials. With this phenomenon in mind, kinetic equations governing the nucleation and growth of microvoids in nonlinear rate-dependent materials are combined with the balance law of void number to establish statistical differential equations that describe the evolution of microvoids' number density. The theoretical solution provides a reasonable explanation of the experimentally observed phenomenon. The effects of stochastic fluctuation which is influenced by the inhomogeneous microscopic structure of materials are subsequently examined (i.e. stochastic growth model). Based on the stochastic differential equation, a Fokker-Planck equation which governs the evolution of the transition probability is derived. The analytical solution for the transition probability is then obtained and the effects of stochastic fluctuation is discussed. The statistical and stochastic analyses may provide effective approaches to reveal the physics of damage evolution and dynamic failure process in ductile materials.