結晶構造体に対する計算力学モデルの検討 : [III]モードIIき裂先端場の原子構造の解析

概要

論文の詳細を見る
The atomic changes of structure around the crack-tip in fcc crystal under in-plane shear (Mode II) loading is analyzed by means of molecular dynamics (MD) simulation. The interatomic force interaction is assumed to be derived from the many body potential proposed by Finnis and Sinclair. The crack surface and its front are assigned to (1) [110] (001), (2) [110] (111), and (3) [110] (110). Both fixed displacement and fixed stress boundary conditions are adopted. The ductile deformation with emission of edge dislocations from crack tip is observed in every case. When the dislocation nucleates, potential energy of the system decreases and kinetic energy increases. Similar problems are analyzed using the continuum model with FEM based on the crystalline plasticity theory. The trail of dislocation in the atomistic model corresponds with shear slip in the continuum model. From the result of MD simulation, the dislocation emission condition may be described as that the shear stress at a distance of a lattice constant from the crack-tip reaches the ideal shear strength of perfect crystal. The critical stress intensity factor estimated with this condition agrees well with Rice's theoretical prediction.
一般社団法人日本機械学会の論文
1993-08-25