Phenomenological model of local plasticity
Pages 101 - 108
Two points of an elastic and perfectly plastic material exposed to the plane stress are examined by the author. One point is located on the stress concentrator surface. The other one is located at a certain distance from the first one (it is considered as a secondary point within the framework of the kinetic theory of a plastic flow).
As a result of the finite element analysis of the stress-strain state it has been discovered that the material in the point located in the front area of the kinetic plastic flow remains linearly elastic in terms of its physical condition, and the load is applied to it in accordance with a curved trajectory. This trajectory is represented by coordinates, where Uф and U0 are the density-related components of dilatation and distortion strain. For the purposes of modeling, the trajectory is represented as a two-component broken line.
As a result, the kinetic plastic flow prolongation is limited. This effect intensifies while the value of the elastic Poisson ratio (µ) goes down. For example, for ? < 0.5, dimensions of the plastic zone outstretched along the crack curve are smaller than those identified using the Irwin plastic zone solution. Furthermore, in case of ? = 0.25, the effective crack length is , and the modified stress distribution is below the singular stress distribution according to the laws of linear elastic fracture mechanics.
DOI: 10.22227/1997-0935.2012.9.101 - 108
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