A Model of an Asymmetric Weakened Zone in Problems of Interaction Between Cracklike Defects in an Elastic Medium

摘要

A weakened zone of a deformed solid medium can be denned as a cut in its volume. In this case, the entire surface of cut edges is subjected to the action of distributed adhesive forces, whereas displacements exhibit discontinuities [1]. This object can be treated as a forerunner of a crack. With increasing load on a solid when the bonds begin to break and traction-free zones appear on the edges of a cut, the weakened zone transforms into a crack. The fundamental difference between a weakened zone and a crack is that the opening of the weakened zone does not occur immediately, but on attaining a certain load level sufficient to overcome the initial adhesive forces. These forces can be of different physical natures, e.g., of an atomic-molecular or dislocation character. In addition, these forces can arise due to the presence of porosity, fibers, plastic hinges, etc. The scale of linear sizes of a weakened zone ranges from nanometers and micrometers (new materials) to kilometers (welded cracks in glaciers and faults in the earth's crust).