A movie of stress distribution on crack-tip based on MD method

Kejie Zhao — Sat, 13 Oct 2007 05:38:02 -0400

When I am clearing up reference dates on my computer, I just find this movie showing the stress distribution on crack tip field based on MD simulation. This work was done in my first year graduation study, and my focus is try to give a "real" stress distribution on the plasticity tip compared to the theoritical asymptotic solution. I remember the straight crack front is lying on a (111) plane and runs along [-110] direction, and a layer of atoms is removed from the perfect cylindrical sample, to generate a stable but slightly blunt crack. Then after relaxing the system with conjugate gradient method, we apply incrementally the mode I loading by a stress intensity factor K. During this process, the outermost atoms are fixed, and the atom positions are determined by the linear elastic Stroh solution. Then the other atoms "feel" the traction induced by the boundary atoms, and moved under the interaction force of EAM potentials. This methodology cited Dr. Ting Zhu's work. And the Virial stress definition is adopted to plot this distribution movie during each loading level.

However, as the plasticity field is too small, about several hundreds of atoms, The corresponding stress distribution may be not statistically reliable. This may be partially due to the materials choosen to study. With this consideration, I stopped this challenging topic and regretively no report has been made. But I now still think it interesting and maybe it could give some reference for the simulation of crack.

Since the related dates lost, I am sorry that I have no methods to polish this movie.

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A movie of stress distribution on crack-tip based on MD method