The simplified model of numerical analyses of discrete dislocation motion and emission
from a stressed source was applied to predict the yield stress, dislocation creep, and fatigue crack
growth rate of metals dominated by dislocation motion. The results obtained by these numerical
analyses enabled us to link various dynamical effects on the yield stress, dislocation creep, and
fatigue crack growth rate with the experimental results of macroscopic phenomena, as well as to
link them with theoretical results obtained by the concept of static, continuously distributed
infinitesimal dislocations for the equilibrium state under low strain or stress rate conditions. This
will be useful to holistic research approaches with concern for time and space scales, that is, in a
time scale ranging from results under high strain rate condition to those under static or low strain
rate condition, and in a space scale ranging from meso-scale to macro-scale mechanics. The
originality of results obtained by these analyses were found by deriving the analytical formulations
of number of dislocation emitted from a stressed source and a local dynamic stress intensity factor
at the pile-up site of dislocations as a function of applied stress or stress rate and temperature
material constants. This enabled us to develop the predictive law of yield stress, creep deformation
rate, and fatigue crack growth rate of metals dominated by dislocation motion. Especially, yielding
phenomena such as the stress rate and grain size dependence of yield stress and the delayed time
of yielding were clarified as a holistic phenomenon composed of sequential processes of dislocation
release from a solute atom, dislocation group moving, and stress concentration by pile-up at the
grain boundary.




中文翻译：

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基于位错群动力学简化模型的金属屈服，蠕变和疲劳裂纹扩展速率研究的整体方法

离散的位错运动和
来自应力源的发射的数值分析的简化模型被用来预测
由位错运动主导的金属的屈服应力，位错蠕变和疲劳裂纹增长率。通过这些数值
分析获得的结果使我们能够将对屈服应力，位错蠕变和
疲劳裂纹增长率的各种动力学影响与宏观现象的实验结果
联系起来，并将它们与通过静态概念获得的理论结果联系起来，
在低应变或应力率条件下连续分布无穷小的位错，达到平衡状态。这个
对于关注时间和空间尺度的整体研究方法将是有用的，也就是说，在
从高应变率条件下的结果到静态或低应变
率条件下的结果的时间尺度以及在中尺度范围内的空间尺度宏观力学。
通过得出
应力源发出的位错数量和位错
堆积部位处的局部动应力强度因子作为施加应力或应力速率和温度的函数的分析公式，可以找到通过这些分析获得的结果的独创性。
材料常数。这使我们能够制定屈服应力，蠕变变形的预测规律。
速度和位错运动主导的金属的疲劳裂纹扩展率。特别是，
诸如应力率，屈服应力的晶粒尺寸依赖性以及屈服延迟时间
之类的屈服现象已被阐明为一种整体现象，其由
溶质原子从位错释放，位错基团移动以及堆应力集中的顺序过程组成。在
晶界处。